PinoyBIX Engineering Problem Solving and Reference

This is the Self-test in Chapter 14: Modern Communications Applications from the book COMMUNICATIONS ELECTRONICS by Louis E. Frenzel. If you are looking for a reviewer in Communications Engineering this will definitely help. I can assure you that this will be a great help in reviewing the book in preparation for your Board Exam. Make sure to familiarize each and every questions to increase the chance of passing the ECE Board Exam.

Start Practice Exam Test Questions

Direction: Either Supply the missing word(s) in each statement  or Choose the letter that best answers each question.

1. Images are converted into electrical signals by a process of _____ with a light source and photosensitive detector.

2. The most common transmission medium for fax signals is _____.

3. Standards for fax transmission are set by the _____.

4. The modulation method used in group 1 machines was PM with black = _____ Hz and white= _____ Hz.

5. Vestigial sideband AM is used in group _____ machines.

6. The photosensitive device used in most modern fax machines to convert a scanned line into an analog signal is a(n)

7. Most modem fax machines are of the group _____ type.

8. To ensure compatibility between sending and receiving fax machines, control logic carries out the process of _____ by audio tones prior to transmission.

9. The most commonly used type of printer in a fax machine is a(n) _____ printer.

10. The upper speed limit of a G3 fax machine over telephone lines is _____ baud.

11. The resolution of a G3 fax machine is typically _____ lines per-inch.

12. The two modulation techniques used in G3 machines are _____.

13. A fax transmission is usually _____ (full, halt) duplex.

14. The speed and resolution of group 4 fax transmissions are _____ kbits/s and _____ lines per inch.

15. True or false. Fax can transmit photos and drawings as well as printed text.

16. True or false. Fax signals may not be transmitted by radio.

17. True or false. Group 4 transmission do not use the standard telephone lines.

18. The area to be served by a cellular telephone system is divided into adjacent _____.

19. The master control station for a group of cells is called the _____.

20. Name two reasons why there are more channels, available in cellular systems than in older mobile telephone systems.

21. The number of channels available is _____.

22. True or false. Cellular telephone radios operate full duplex.

23. The type of modulation used in a cellular radio is _____.

24. The maximum power output of a cellular transmitter is _____ W.

25. The transmit frequency range is _____ to _____ MHz.

26. The receive frequency range is _____ to _____ MHz.

27. Channels pacing is _____ kHz.

28. Separation between send and receive frequencies is _____ MHz.

29. Transmit and receive frequencies are determined by a(n) _____.

30. Common first IFs are _____ and _____ MHz. Common second IFs are _____ and _____ MHz.

31. The APC circuit causes the transmitter power to _____ based on an input control signal from the MTSO.

32. A _____ allows the transmitter and receiver to share an antenna.

33. True or false. The transmit and receive channel is selected by the operator. .

34. The source of the frequency divider ratios in the frequency synthesizer PLLs is the _____.

35. Name two signals that are transmitted back to the cell site and are monitored by the MTSO.

36. Name three conditions in the transceiver that are controlled by the MTSO.

37. A dc signal derived from the demodulator and used to tell the MTSO about received signal strength is called the _____.

38. A receiver has a first IF of 82.2 MHz. The second IF is 456 kHz. The LO frequency on the second mixer is _____ MHz.

39. The section of the cellular transceiver that interprets the serial digital data from the cell site and MTSO is the _____ unit.

40. How many microprocessors do most cellular transceivers contain?

41. The handset is part of the _____ section of the transceiver.

42. When the speed of radio signals is known, radar can be used to determine the _____ of a target.

43. An echo is the _____ from a target.

44. The directivity of the radar antenna determines the _____ of a target.

45. The speed of a radar signal is _____ s/nmi.

46. The elapsed time between radiating a radar signal and receiving its echo is 43.2 s. The target distance in nautical miles is _____.

47. If a target is 1000 yd away, the time period between the transmission of the signal and receipt of the echo is _____ s.

48. One nautical mile is equal to _____ statute miles.

49. For optimum reflection from a target, the wavelength of the radar signal should be _____ compared to the size of the target.

50. Radars operate in the _____ frequency range.

51. True or false. Both the transmitter and receiver in a radar share the same antenna.

52. The two main types of radar are _____.

53. A frequency shift of sound, radio, or light waves that occurs as the result of the relative motion between objects is called the _____ effect.

54. A CW radar operates at a frequency of 14 GHz. A frequency shift of 25 kHz is produced by a moving target. Its speed is _____ mi/h.

55. True or false. Distance can be measured with constant-frequency CW radar.

56. A waveguide assembly that lets the transmitter and receiver share an antenna is called a(n) _____.

57. The most commonly used component in a radar transmitter is a(n) _____ tube.

58. Both TR and ATR tubes incorporate a(n) _____.

59. The output display in a radar is usually a(n) _____.

60. A display that sweeps outward from the center of the screen while rotating is known as a(n) _____.

61. A radar using multiple antennas to shape the beam width and automatically adjust directivity is known as a(n) _____ radar.

62. The bandwidth of a standard TV signal is _____ MHz.

63. The video carrier is _____ modulated and the sound carrier is _____ modulated.

64. The spacing between the sound and picture carriers is _____ MHz.

65. TV stations operate in the _____ and _____ regions of the spectrum.

66. The brightness signal produced by a video camera is called the _____ or _____ signal.

67. Two electronic imaging devices used in TV cameras to produce video signals are the _____ and the _____.

68. The process that breaks up a picture or scene into serially transmitted signals is called _____.

69. The three basic colors of light which can be used to produce any other color are _____ , _____, and _____.

70. A NTSC TV picture or one frame of video is composed of _____ scan lines.

71. A field consists of _____ scan lines.

72. The field and frame rates are _____ and _____ Hz respectively.

73. The time needed to scan one horizontal line in a color TV set is _____.

74. To keep the picture at the receiver in step with the transmitted signal, _____ are added to the video.

75. The circuit that lets the picture and sound transmitters use the same antenna is the _____.

76. The color in a scene is generated by a camera that develops three signals that represent the amount of _____, _____, and _____ light present along every scan line.

77. The red, greed, and blue color signals are combined in a resistive matrix to produce the two color signals called _____ and _____.

78. The two color signals are fed to _____ circuits that produce _____ modulation.

79. The color signals modulate a subcarrier with a frequency of _____.

80. The characteristic of the composite color signal that tells the receiver the transmitted color is its _____.

81. The _____ signal can be formed by adding the color signals in the following proportion: 0.11B +0.59G + O.3R.

82. Channel selection in the tuner is accomplished by using a(n) _____ for a local oscillator.

83. The _____ portion of a modern TV set uses digitally coded infrared signals for channel, volume, and other changes.

84. A channel 33 UHF TV station has a picture carrier frequency of 585.25 MHz. The sound carrier frequency is _____.

85. The frequency of the video signal representing fine detail along a scan line can have a frequency up to about _____.

86. The TV receiver sound IF is _____ MHz, and the picture IF is _____ MHz.

87. The name of the special filter that provides most of the adjacent channel selectivity for the TV receiver is _____.

88. Spectrum space is conserved by using _____ modulation for the video in a TV signal.

89. In the TV receiver, the picture and sound IF beat together to form the sound IF of _____ MHz.

90. Two common sound demodulators in TV receivers are the _____ and the _____.

91. The composite color signal is demodulated in two _____ demodulator circuits fed with quadrature 3.58-MHz signals from a subcarrier oscillator.

92. The. 3.58-MHz subcarrier oscillator in the receiver is phase- and frequency-synchronized to the _____ signal transmitted along with the horizontal sync pulses.

93. The _____ circuit strips the horizontal sync pulses from the video detector output.

94. The horizontal sync pulses synchronize in internal sweep oscillator to a frequency of _____ Hz.

95. The vertical sweep oscillator is synchronized to a frequency of _____ Hz by as sync pulse derived by _____ the horizontal sync pulses occurring during the vertical blanking interval.

96. The horizontal and vertical sweep signals are currents with the shape of a(n) _____.

97. The sweep signals are applied to the _____ assembly around the neck of the picture tube.

98. The electron beam is generated by the _____ element in the picture tube and focused into a narrow beam by the

99. The electron beam is deflected and swept across the face of the picture tube by _____ generated by the _____.

100. A color CRT contains _____ electron guns to excite the color dot triads on the face of the tube.

101. The _____ circuits ensure that the electron beams strike the correct color dots.

102. The _____ stage is used as switching power supply to develop the HV required to operate the picture tube.

103. The transformer used to step up and step down the horizontal sync pulses is called the _____.

104. The name given to the cable TV station that collects and distributes the cable signals is _____.

105. The, main cables used to distribute the TV signals to subscribers are called the _____ and _____.

106. The coaxial cables that feed individual houses are called _____ and typically have a characteristic impedance of _____ ohms.

107. The cable TV station may change the TV signal frequency by translating it to another frequency by using a _____.

108. Cable attenuation occurring during distribution is overcome by using _____.

109. The cable box used by the subscriber contains two, main circuits, the _____ and the _____.

110. The output of the cable box is a TV signal on channel _____ or _____ that is connected to the _____ of the TV set.

111. Four advantages of cable TV are _____, _____, _____, and _____.

Check your work.

Complete List of Self-test and Reviewers in Communications Electronics

---

This is the Self-test in Chapter 13: Fiber-Optics Communications from the book COMMUNICATIONS ELECTRONICS by Louis E. Frenzel. If you are looking for a reviewer in Communications Engineering this will definitely help. I can assure you that this will be a great help in reviewing the book in preparation for your Board Exam. Make sure to familiarize each and every questions to increase the chance of passing the ECE Board Exam.

Start Practice Exam Test Questions

Direction: Either Supply the missing word(s) in each statement  or Choose the letter that best answers each question.

1. Fiber-optic cables carry _____ rather than electrical signals.

2. The three main types of information carried by fiber optic-cables are _____, _____, and _____.

3. The major use of fiber-optic cables is in _____.

4. Fiber-optic cables are made of _____ or _____.

5. The main benefit of fiber-optic cable over electric cable is its _____.

6. True or false. Fiber-optic cable has more loss than electric cable over long distances.

7. True or false. Fiber-optic cable is smaller, lighter, and stronger than electric cable.

8. List the two main disadvantages of fiber optic cable.

9. The two most commonly used light sources in fiber-optic systems are _____.

10. Voice and video signals are converted into before being transmitted by a light beam.

11. The device that converts the light pulses into an electrical signal is a(n) _____.

12. Regenerative units called _____ are often used to compensate for signal attenuation over long distances.

13. Light is a type of _____ radiation.

14. A fiber-optic cable can be viewed as a light _____.

15. Light travels in a

• a. Circle
• b. Straight line
• c. Curve
• d. Random way

16. The wavelength of light is usually expressed in _____ or _____.

17. The lowest-frequency visible light is

• a. Red
• b. Violet

18. A micrometer, or micron, is a length of _____ of a _____.

19. The wavelength range of visible light is _____ to _____ nm.

20. Infrared light has a wavelength that is

• a. Less than 400 nm
• b. More than 700 nm
• c. Less than 700 nm

21. The optical spectrum is made up of what three parts?

22. The speed of light in air is _____ m/s or _____ mi/s.

23. True or false. The speed of light is slower in glass or water than it is in air.

24. The number that tells how fast light travels in a medium compared to air is the _____ of _____.

25. Light beams can be bounced or their direction can be changed by _____ with a(n) _____.

26. The bending of light rays due to speed changes when moving from one medium to another is called _____.

27. If a light ray strikes a mirror at an angle of 30° from the normal, it is reflected at an angle of _____ ° from the normal.

28. When the angle of refraction is 90° to the normal, the ray travels along the _____ between the two media. Therefore, the incident ray strikes the surface at the _____ angle.

29. When the incident ray strikes the interface at an angle greater than the critical angle, _____ occurs.

30. The critical angle depends upon the value of the _____ of _____.

31. Which material has the best optical characteristics and lowest loss?

• a. Plastic
• b. Glass
• c. they are equal

32. The core is protected by the _____.

33. In PCS cable, the core is _____ and the cladding is _____.

34. The index of refraction is highest in the

• a. Core
• b. Cladding

35. List the three main types of fiber-optic cable.

36. Stretching of the light pulse is called _____.

37. List the two types of cable in which light pulse stretching occurs.

38. High-frequency pulses can be best transmitted over _____ cable.

39. Pulse stretching causes the information capacity of a cable to

• a. Increase
• b. Decrease

40. Graded index means that the _____ of _____ of the core varies over its cross section

41. Single-mode step-index cable has a Core diameter in the range of

• a. 100 to 1000 m
• b. 50 to 100 m
• c. 2 to 15 m

42. A _____ is applied over the cladding to protect against moisture, damage, etc.

43. A common protective layer in a cable is made of _____ mesh.

44. Fiber-optic cables are available with the following number of cores: _____.

45. Light loss in a cable is called _____.

46. Light loss is caused by _____.

47. Light loss is measured in _____ per_____.

48. A cable with a loss of 5 dB will have _____ percent of the input appear at the output (see Fig. 13-19). (page 365-Frenzel)

49. True or false. A kilometer is longer than a mile.

50. Which cable length will have the least attenuation?

• a. 40 ft
• b. 120 ft
• c. 1780 ft
• d. 1 km

51. Three cables with attenuations of 9, 22, and 45 dB are spliced together. The total attenuation is _____ dB.

52. True or false. Fiber-optic cables may be spliced.

53. To conveniently link and attach fiber-optic cables to one another and related equipment, _____ are used.

54. The two most common light sources used in fiber-optic transmitters are _____.

55.The most popular light wavelength is _____ m because fiber-optic cable attenuation is lowest at that wavelength.

56.True or false. The light from a 1.55 m LED is visible.

57. Usually LEDs are made of _____.

58. Single frequency light is called _____.

59. The condition of all emitted light waves being in phase is known as _____.

60. A single-frequency intense light source is known as a(n) _____.

61. The reflective surfaces on a laser diode structure form a(n) _____ that produces in-phase light waves.

62. For normal operation, LED and ILDs are _____ (reverse, forward)-biased.

63. Which is faster, an LED or ILD?

64. Which produces the brightest light, an LED or ILD?

65. During normal operation, all photodiodes are _____ (reverse, forward)-biased.

66. Light falling on the PN junction of a photodiode causes the diode's _____ current to increase.

67. The most sensitive and fastest light detector is the _____.

68. 68-.The two main circuits in a fiber-optic receiver are _____.

69. The product of the bit rate and distance of a system is 90 Mbits·km/s. The rating at 3 km is _____ Mbits/s.

70. In today's systems, the average maximum distance between repeaters is between _____ and _____ mi.

Check your work.

Complete List of Self-test and Reviewers in Communications Electronics

---

This is the Self-test in Chapter 12: Data Communications from the book COMMUNICATIONS ELECTRONICS by Louis E. Frenzel. If you are looking for a reviewer in Communications Engineering this will definitely help. I can assure you that this will be a great help in reviewing the book in preparation for your Board Exam. Make sure to familiarize each and every questions to increase the chance of passing the ECE Board Exam.

Start Practice Exam Test Questions

Direction: Either Supply the missing word(s) in each statement  or Choose the letter that best answers each question.

1. Data communications is the transmission of _____ information.

2. True or false. Audio and video signals may be transmitted using data communications techniques.

3. The earliest form of data communications was the _____.

4. The earliest form of radio data communications is known as _____.

5. The Morse code is made up of combinations of _____ and _____ to represent characters.

6. Give the Morse code for the following characters (see Fig. 12-2): K, 8, ,. (page 310-Frenzel)

7. The 5-bit code used in teletype systems is called the _____ code.

8. A system of data communications using type writer like devices to send and receive coded messages is known as _____.

9. If in the Baudot code the character 11011 is sent and then the code 00111, the character _____ is received.

10. The most widely used binary data code is _____ which uses 7 bits to represent characters.

11. An 8-bit data code used in IBM systems is known as _____.

12. Write the ASCII codes for the following characters: B, 3, ?

13. What ASCII character is transmitted to ring a bell? BEL = _____.

14. The two types of data transmission are _____.

15. True or false. Serial data transfers are faster than parallel transfers.

16. The digital circuit often used to perform parallel-to-serial and serial-to-parallel data conversions is the _____

17. In asynchronous transmissions, _____ and _____ bits are used to signal the beginning and end of a character.

18. The speed of a serial data transmission is usually expressed in _____.

19. The number of symbols occurring per second in a data transmission is called the _____.

20. True or false. There can be more than i bit per baud in data transmissions.

21. True or false. Asynchronous transmission is faster than synchronous transmission.

22. In synchronous data transmission, data is sent in _____ of characters with special codes to signal the beginning and end.

23. In serial data transmission, a binary 0 is called a(n) _____ and a binary 1 is called a(n) _____.

24. The study of efficient information transfer is known as _____.

25. The amount of information transmitted is proportional to the system _____ and the _____ allowed for transmission.

26. The channel capacity of a 5-kHz bandwidth binary system is _____ bits/s assuming no noise.

27. If an 8-level encoding scheme is used in a 100 kHz bandwidth system, the channel capacity is _____ bits/s.

28. True or false. Multilevel or multi-symbol binary encoding schemes permit more data to be transmitted in less time, assuming a constant symbol interval.

29. By using a multi-symbol encoding scheme, a higher bit rate can' be achieved with _____ (more, less) bandwidth.

30. The channel capacity of a 6-MHz channel with an SIN ratio of 25 dB is _____ Mbits/s.

31. The minimum allowable bandwidth for a binary signal with a bit rate of 200 kbits/s is _____ kHz.

32. A modem contains both _____ and _____ circuits.

33. Modems convert _____ signals to _____ signals and vice versa.

34. The transmission medium most widely used with modems is the _____.

35. Modems are the interface between _____.

36. _____ modulation is used in low speed modems.

37. In FSK, binary 0 and I levels are represented by different _____.

38. In an FSKs modem, a high frequency represents a(n) _____ and a low frequency represents a(n) _____.

39. The typical frequencies used in a full duplex FSK modem are as follows:

• originate 0 _____ Hz and 1 _____ Hz;
• answer 0 _____ Hz and 1 _____ Hz.

40. The IC used to perform serial-to-parallel and parallel-to-serial conversions and other operations in a modem is known as a(n) _____.

41. The modulation method that represents bits as different phase shifts of a carrier is known as _____.

42. In BPSK, phase shifts of _____ degrees and _____ degrees used to represent bif\ary 0 and binary 1, respectively.

43. The circuit used to produce BPSK is a(n) _____.

44. The circuit-used to demodulate BPSK is a(n) _____.

45. A(n) _____ circuit is used to generate the carrier to be used in demodulating a BPSK signal.

46. A carrier recovery circuit is not needed with _____ PSK modulation.

47. The key circuit used in a DPSK modulator is the _____.

48. The number of different phase shifts used in QPSK is _____.

49. In QPSK, how many bits are represented by each phase shift?

50. The number of bits represented by each phase shift in 16-PSK is _____.

51. The circuit used to create a dibit is known as a(n) _____.

52. A circuit that converts a 2-bit binary code into one of four dc voltage levels is known as a _____.

53. Quadrature amplitude modulation is a combination of _____ modulation and _____ modulation.

54. True or false. Modems must transmit signals in the 300-Hz to 3-kHz range.

55. True or false. Carrier recovery is not required in a QPSK demodulator.

56. True or false. When QPSK is used, the bit rate is faster than the baud (symbol) rate.

57. True or false. Each phase and/or amplitude change can represent only one bit.

58. True or false. With QAM, a 9600 bits/s signal can be transmitted within a 3000-Hz bandwidth.

59. Rules and procedures that describe how data will be transmitted and received are referred to as _____.

60. List five methods of error detection and correction.

61. The process of exchanging signals between transmitter and receiver to indicate status or availability is called _____.

62. A popular protocol used in personal computer data communications is known as _____.

63. A string of characters making up a message or part of a message is referred to as a(n) _____ of data.

64. Stop and start bits are used with, _____ (asynchronous, synchronous) data.

65. Synchronous protocols usually begin with the _____ character.

66. The characters that indicate message number, destination, or other facts are collectively referred to as the _____.

67. The _____ character designates the beginning of a message, while the character _____ indicates its end.

68. One simple but time-consuming way to ensure an error-free transmission is to send the data multiple times. This is called _____.

69. One type of special self checking error code is the _____ code.

70. Errors in data transmission are usually caused by _____.

71. The ratio of the number of bit errors to the total number of bits transmitted is known as the _____.

72. A bit added to the transmitted character to help indicate an error is called the _____ bit.

73. A number added to the end of a data block to assist in detecting errors is known as the _____

74. Write the correct parity bits for each number.

• a. Odd: 0011000 _____
• b. Even: 1111101 _____
• c. Odd: 0101101 _____
• d. Even: 1000110 _____

75. Another name for parity is _____.

76. The basic building block of a parity generator circuit is the _____ gate.

77. Performing an exclusive OR on corresponding bits in successive data words produces a(n) word.

78. An error-detection system that uses a BCC at the end of a block is known as a(n) _____.

79. Dividing the data block by a constant produces a quotient that is discarded and a remainder called the _____ character.

80. The CRC circuit is basically a(n) _____.

81. True or false. If a bit error cart be identified, it can be corrected.

82. The telephone system is an example of a _____.

83. True or false. A cable TV system is considered a network.

84. Most networks re smaller and cover shorter distances and are referred to as _____.

85. The acronym PBX means _____.

86. True or false. PBXs cannot be used with digital data.

87. The three main types of LAN topologies are _____.

88. A PBX is a type of _____ topology LAN.

89. An LAN that uses a central controller for multiple stations is the _____ topology.

90. One type of LAN connects multiple terminals and PCs to a large central _____ computer.

91. A LAN in which the message is passed from one station to the next until the destination is reached is called a(n) _____.

92. The stations or users in a network are referred to as _____.

93. A network in which all stations attach to a common cable is called a(n) _____.

94. 94: The fastest network configuration is the _____.

95. In a(n) _____ LAN configuration, if one station fails, the whole system fails.

96. A connection from a LAN to a mainframe computer is known as a(n) _____.

97. A connection from one LAN to another is called a(n), _____.

98. The three transmission media used in LANs are _____.

99. An extended variation of the bus topology is called the _____.

100. List the three main disadvantages of twisted pair cable.

101. _____ is the most widely used medium in LANs.

102. The medium that permits the highest data rates is _____.

103. The longest transmission distances can be achieved with _____ medium.

104. Give the average maximum data rates in Mbits/s for each medium: twisted pair, coax, fiber-optic cable.

105. The digital, voice, or video voltages are referred to as _____ signals.

106. When the basic data signal is sent directly over the medium, the type of operation is said to be _____.

107. _____ operation uses modulation techniques and FDM techniques to increase speed and the number of operational channels.

108. Broadband operation requires the use of a(n) _____ at each node.

109. Spread spectrum is both a _____ and a _____ technique.

110. The two main types of spread spectrum are _____ and _____.

111. In a frequency-hopping SS system, a _____ circuit generates the transmitter frequency.

112. In a frequency-hopping SS system, a _____ circuit selects the frequency produced by the synthesizer.

113. True or false. The hop rate is slower than the bit rate of the digital data.

114. To a narrowband receiver, an SS signal appears as a type of _____.

115. Two or more stations using SS and sharing a common band are identified and distinguished from one another by their unique _____.

116. The length of time a frequency-hopping SS transmitter stays on one frequency is called the _____.

117. In a direct-sequence SS transmitter, the data signal is mixed with a PSN signal in an _____ circuit.

118. True or false. In a direct-sequence SS system, the chip rate is faster than the data rate.

119. The type of modulation used with direct sequence SS is usually _____.

120. The most difficult part of SS communications is initiating and maintaining _____ prior to and during transmission.

121. The process of comparing one direct sequence SS signal to another in an effort to obtain a match is called _____.

122. The two main benefits of SS are _____ and _____.

123. The main circuit used in making a PSN code generator is a _____.

124. The frequencies allocated to spread spectrum by the FCC for civilian applications are _____, _____, and _____ MHz.

125. Two growing applications for SS are _____ and _____.

Check your work.

Complete List of Self-test and Reviewers in Communications Electronics

---

This is the Self-test in Chapter 11: Introduction to Satellite Communications from the book COMMUNICATIONS ELECTRONICS by Louis E. Frenzel. If you are looking for a reviewer in Communications Engineering this will definitely help. I can assure you that this will be a great help in reviewing the book in preparation for your Board Exam. Make sure to familiarize each and every questions to increase the chance of passing the ECE Board Exam.

Start Practice Exam Test Questions

Direction: Either Supply the missing word(s) in each statement  or Choose the letter that best answers each question.

1. A satellite is kept in orbit by a balance between two forces: _____.

2. A satellite that revolves in the same direction as the earth rotates is said to be in a _____ (posigrade, retrograde) orbit.

3. The geometric shape of a noncircular orbit is a(n) _____.

4. The center of gravity of the earth is called the _____.

5. The time for one orbit is called the _____.

6. The angle of inclination of a satellite is _____ degrees if it orbits over the equator and is _____ degrees if it orbits over the north and south poles.

7. To prevent excessive signal attenuation and noise in the atmosphere, satellite angles of elevation of less than _____ degrees should be avoided.

8. A satellite that rotates around the equator 22,300 mi from the earth is said to be in _____ orbit.

9. Small jet thrusters on a satellite are fired to correct the satellite’s _____.

10. Name two ways satellites are stabilized in space.

11. The three axes of a satellite are _____.

12. The point on the earth directly below a satellite is called the _____.

13. Satellites are located by earth coordinates expressed in terms of _____.

14. The two angles used to point a ground station antenna are _____.

15. A satellite is put into final geosynchronous orbit from its transfer orbit by firing the _____.

16. The most common use of a satellite is _____.

17. A communications satellite is basically a radio _____.

18. A(n) _____ transmits an up-link signal to the satellite.

19. The signal path from a satellite to a ground station is called the _____.

20. The basic communications electronics unit on a satellite is known as a(n) _____.

21. Most communications satellites operate in the _____ frequency range.

22. The most popular satellite frequency range is 4 to 6 GHz and is called the _____ band.

23. Military satellites often operate in the _____ band.

24. The Ku band extends from _____ to _____ GHz.

25. The bandwidth of a typical satellite is _____ MHz.

26. A typical C band transponder can carry _____ channels, each with a bandwidth of _____ MHz.

27. The term used to refer to the technique of using antenna polarization to separate signals on the same frequency to double the number of channels is _____.

28. Using very narrow beam width antennas to isolate signals on the same frequency is known as _____.

29. The most common baseband signals handled by a satellite are _____.

30. The input circuit to a transponder is the _____.

31. List the three main functions of a transponder.

32. A(n) _____ circuit in the transponder performs the frequency conversion.

33. Power amplification in a transponder is usually provided by a(n) _____.

34. A(n) _____ transponder provides amplification at an IF of 70 or 150 MHz.

35. A transponder that demodulates the baseband signals and then remodulates a carrier is known as a(n) _____ transponder.

36. The circuit that provides channelization in a transponder is the _____.

37. The two basic architectures for multichannel transponders are _____.

38. The main power supplies in a satellite are the _____.

39. During an eclipse, the satellite is powered by _____.

40. The TTC subsystem is used to _____ operations on a satellite.

41. Attitude correction is made by firing _____.

42. The signals to be communicated by' the earth station to the satellite are known as _____ signals.

43. The receive or up-link subsystem uses a _____ to translate the satellite signal to an IF before demodulation and demultiplexing.

44. A common IF in an earth station receiver is _____ MHz.

45. The functions performed by the receive GCE section are _____.

46. The functions performed by the transmit GCE section are _____.

47. The two types of modulation used in the transmit GeE are _____.

48. A(n) _____ in the transmit subsection translates the modulated signal to the final transmission frequency.

49. _____ are often used to replace Los for channel selection in earth station transmitters and receivers.

50. List the three main types of power amplifiers used in earth stations.

51. Most earth stations operate from the ac power line but have built-in _____ for emergency operation.

52. True or false. All earth stations contain telemetry, control, and instrumentation subsystems.

53. The main use of satellites is for _____.

54. Name four types of surveillance sensors.

55. What are the name and the purpose of the 24-satellite system developed by the military?

56. Name three uses for surveillance satellites.

57. Consumers use satellites for _____.

Check your work.

Complete List of Self-test and Reviewers in Communications Electronics

---

This is the Self-test in Chapter 10: Microwave Techniques from the book COMMUNICATIONS ELECTRONICS by Louis E. Frenzel. If you are looking for a reviewer in Communications Engineering this will definitely help. I can assure you that this will be a great help in reviewing the book in preparation for your Board Exam. Make sure to familiarize each and every questions to increase the chance of passing the ECE Board Exam.

Start Practice Exam Test Questions

Direction: Either Supply the missing word(s) in each statement  or Choose the letter that best answers each question.

1. Microwaves are frequencies above _____ GHz,

2. The main advantage of microwaves is that more of the _____ is available for signals.

3. List seven reasons why microwaves are more difficult to work with than lower frequency signals.

4. The applications most commonly found in the microwave region are _____ and _____.

5. List four popular uses for microwaves.

6. The government agency that regulates radio communications in the United States is the _____.

7. Name four techniques that have helped squeeze more signals into the given spectrum.

8. Two reasons why conventional transistors won't work at microwave frequencies are _____ and _____.

9. At microwave frequencies, conventional components like resistors, capacitors, and inductors act like _____ circuits.

10. The TV channels 2 to 13 occupy a total bandwidth of about 72 MHz. At a frequency of 200 MHz, this represents a bandwidth of _____ percent of the spectrum space. At 2 GHz, it represents _____ percent.

11. True or false. Twin lead is not used at microwave frequencies.

12. The main disadvantage of using coax for microwave signals is its high _____.

13. Coax is not used beyond frequencies of about _____ GHz.

14. A hollow metal pipe used to carry microwaves is called a(n) _____.

15. Two types of transmission line made of PCB material used to produce tuned circuits and filters are _____.

16. The two ways to couple or extract energy from a waveguide are by using a _____ or a _____.

17. A waveguide acts as a(n) _____ filter.

18. A rectangular waveguide has a width of 1.2 in. and a height of 0.7 in. The waveguide will pass all signals above _____ GHz.

19. A waveguide has a cutoff frequency of 5 GHz.

a. True or false. It will pass a signal of 8 GHz.

b. True or false. It will pass a signal of 3 GHz.

20. The magnetic and electric fields in a waveguide are designated by the letters _____ and _____, respectively.

21. The basic operating mode of most waveguides is designated _____.

22. If the H field in the waveguide is perpendicular to the direction of signal travel, the mode is said to be _____.

23. A one-half wavelength section of waveguide shorted at both ends creates a(n) _____.

24. A cavity resonator acts as a(n) _____ circuit.

25. Resonant cavities are used as _____.

26. Mechanically varying the cavity's dimensions allows its _____.

27. List three reasons why conventional diodes and transistors do not work in the microwave region.

28. A point-contact diode has a(n) _____ anode and a(n) _____ cathode.

29. A microwave diode with an N-type silicon cathode and a metal anode forming a junction is called a(n) _____ diode.

30. The most common application of microwave signal diodes is in _____ circuits.

31. A diode that acts like a VVC is a(n) _____ diode.

32. Two types of diodes widely used as frequency multipliers are the _____ and _____ diodes.

33. A diode with no junction that is widely used with a cavity resonator to form an oscillator is the_____ diode.

34. The _____, _____, and _____ diodes are also used as oscillators.

35. Microwave diodes that cause a current decrease for a voltage increase have what is known as a(n) _____ characteristic.

36. An IMPATT diode operates with _____ (forward, reverse) bias.

37. A tunnel diode operates with _____ (forward, reverse) bias.

38. True or false. Klystrons can be used as amplifiers or oscillators.

39. True or false. A magnetron operates as an amplifier.

40. A TW T is an _____ (amplifier, oscillator).

41. The operating frequency of klystrons and magnetrons is determined by _____.

42. The cavities in a klystron produce _____ modulation of the electron beam.

43. In a klystron amplifier, the input is applied to the _____ cavity and the output taken from the _____ cavity.

44. A one-cavity klystron that oscillates is known as a(n) _____ klystron.

45. Low-power klystrons are being replaced by _____, and high-power klystrons are being replaced by _____.

46. A(n) _____ causes the electrons in a magnetron to travel in circular paths.

47. Two major applications of magnetrons are in _____.

48. The TW T is a microwave _____.

49. Density modulation of the electron beam in a TW T is produced by a(n) _____.

50. The major benefit of a TW T is its wide _____.

51. The most commonly used microwave antenna is the _____ antenna.

52. Increasing the length of a horn antenna causes its gain to _____ and its beam width to _____.

53. A horn antenna is six wavelengths long at 8 GHz. That length is _____ in.

54. The beam width of a horn antenna is usually in the _____ to degree _____ range. ,

55. The width of a horn antenna is 8 cm. The height is 6 cm. The operating frequency is 8 GHz. The beam angle is _____ degrees. The gain is _____ dB. Assume k = 0.5.

56. Horn antennas have _____ (narrow, wide) bandwidth.

57. The geometric shape of a microwave reflector is a(n) _____.

58. In order for a dish, reflector to work, the antenna must be located at the _____ of the dish.

59. The antenna used with a dish reflector is usually a(n) _____.

60. A parabolic reflector antenna has a diameter of 9 m. The frequency of operation is 8 GHz. The gain is _____ dB. The beam width is _____ °.

61. The effect of a parabolic reflector on an antenna is to _____ gain and _____ beam width.

62. A dish with a horn at its center and a small reflector at the focal point is said to use _____ feed.

63. The benefits of a helical antenna are its _____ and _____.

64. The gain of a helical antenna is typically in the _____ to _____ –dB range.

65. The beam width of a helical antenna is in the _____ to _____ degree range.

66. The helical antenna radiates a(n) _____ polarized wave.

67. The acronym RHC P means _____.

68. A popular omni-directional microwave antenna is the _____.

69. True or false. A helical antenna will receive either vertical or horizontally polarized signals.

70. True or false. An RHC P antenna can receive a signal from an L HC P antenna.

Check your work.

Complete List of Self-test and Reviewers in Communications Electronics

---

This is the Self-test in Chapter 9: Antennas and Transmission Lines from the book COMMUNICATIONS ELECTRONICS by Louis E. Frenzel. If you are looking for a reviewer in Communications Engineering this will definitely help. I can assure you that this will be a great help in reviewing the book in preparation for your Board Exam. Make sure to familiarize each and every questions to increase the chance of passing the ECE Board Exam.

Start Practice Exam Test Questions

Direction: Either Supply the missing word(s) in each statement  or Choose the letter that best answers each question.

1. The two basic types of transmission line are _____.

2. If one wire of a transmission line is connected to ground, the line is said to be _____.

3. The distance that a signal travels during one cycle is called the _____.

4. One wavelength that a frequency of 450 MHz is  _____ m.

5. A line 4 in. long represents one-half wavelength at a frequency of _____ GHz.

6. The physical dimensions of a transmission line determine its _____.

7. To a generator, a transmission line looks like a(n) _____ made up of distributed _____ and _____.

8. A coax line has a shield braid with an inside diameter of 0.2 in. and a center conductor with a diameter of 0.057 in. The characteristic impedance is _____ .

9. The attenuation of 250 ft of RG-11U coax at 100 MHz is _____ dB. (SeeFig.9-7) (page 211-Frenzel)

10. For optimum transfer of power from a generator to a load of 52, the transmission line impedance should be _____ .

11. The current and voltage along a properly matched line are _____.

12. If a transmission line is not terminated in its characteristic impedance, _____ will develop along the line

13. If a load and line have mismatched impedances, power not absorbed by the load will be _____.

14. Patterns of voltage and current variations along, a transmission line with a mismatched load are known as _____.

15. A 52- coax bas a 36- antenna load. The SWR is _____.

16. If the load and line impedances are matched, the SWR will be _____.

17. All incident power on a line will be reflected if the line is _____ or _____ at its end.

18. The ratio of the reflected voltage to the incident voltage on a transmission line is called the _____.

19. The maximum voltage along a transmission line is 150V, and the minimum voltage is 90V. The SWR is _____.The reflection coefficient is _____.

20. The reflection coefficient of a transmission line is 0.75. The SWR is _____.

21. An open or shorted transmission line will have a reflection coefficient of _____ and an SWR of _____.

22. Transmission lines, one-quarter or one haIf wavelength can be used as _____.

23. A transmission line bas an SWR of 1.75. The power applied to the line, is 90 W. The amount of reflected power is _____ W.

24. A shorted quarter-wave line looks like a(n) _____ impedance to the generator.

25. The following lines look like a series resonant circuit: a _____ /4 line; a _____ /2 line.

26. Transmission lines less than /4 or between /4 and /2 act like _____ or _____.

27. An open transmission line 6 in. long acts as a _____ resonant circuit at a frequency of 492 MHz.

28. A coax bas a velocity factor of 0.68. One half wavelength of this coax at 120 MHz is _____ ft long.

29. Radio waves are made up of _____ and _____ fields.

30. The polarization of a radio wave depends upon the position of its _____ with respect to the earth's surface.

31. The antenna is connected to the transmitter or receiver by a(n) _____.

32. A radio wave has its magnetic field horizontal to the earth. It is, therefore, _____ polarized.

33. One of the most widely used and simplest antennas is the half-wave _____.

34. The length of a doublet antenna at 150 MHz is _____ ft.

35. The feed impedance of a dipole antenna is approximately, _____ .

36. The horizontal radiation pattern of a dipole looks like a(n) _____.

37. The measure of an antenna's directivity is _____.

38. An antenna that radiates equally well in all horizontal directions is said to be _____.

39. A quarter-wave vertical antenna is commonly known as a(n) _____ antenna.

40. The length of a quarter-wave vertical antenna at 890 MHz is _____ in.

41. For proper operation of a vertical antenna, the shield of the feed coax must make a good connection to _____ or a set of quarter-wave wires called _____.

42. The horizontal radiation pattern of a quarter-wave vertical is a(n) _____.

43. The feed impedance of a quarter-wave vertical is approximately _____ .

44. An antenna that transmits or receives equally well in two opposite directions is said to be _____.

45. A unidirectional antenna transmits best in _____ direction(s).

46. A directional antenna that focuses the energy into a narrow beam has _____ since it effectively amplifies the signal.

47. To have gain and directivity, an antenna must have two or more _____.

48. List two basic types of antenna arrays.

49. The three basic elements in a Yagi antenna are _____.

50. The two parasitic elements in a beam antenna are the _____.

51. A Yagi may have one or more _____ elements.

52. The beam width of a Yagi is usually in the range of _____ to _____ degrees.

53. The length of the driven element in a Yagi at 222 MHz is _____ ft.

54. List three kinds of driven arrays.

55. True or false. Yagis and driven arrays may be operated either horizontally or vertically.

56. A popular wideband driven array is the _____ array.

57. An impedance-matching circuit used to make the antenna, transmission line, and transmitter impedances match is the _____.

58. A transformer used for impedance matching is the _____.

59. A quarter-wavelength section of transmission line used for impedance matching is called a(n) _____.

60. A coax balun has an impedance-matching ratio of _____.

61. A quarter-wavelength of coax with a velocity factor of 0.7 at 220 MHz is _____ in.

62. List the three paths that a radio signal may take through space.

63. A radio wave that propagates near the surface of the earth is called a(n) _____ or _____ wave.

64. The radio wave that is refracted by the ionosphere is known as a(n) _____ wave.

65. A radio wave that propagates only over line-of-sight distances is called a(n) _____ or _____ wave.

66. The surface wave is effective only at frequencies below about _____ MHz.

67. The upper part of the earth's atmosphere ionized by the sun that affects radio waves is called the _____.

68. The _____ layer has the greatest effect on a radio signal.

69. The ionized atmosphere causes radio waves at some frequencies to be _____.

70. True or false. Radio waves are easily reflected by large objects.

71. True or false. The ionosphere reflects radio waves.

72. Only signals in the _____ to _____ MHz range are significantly affected by the ionosphere.

73. Worldwide radio communications is possible thanks to _____ transmission.

74. The VHF, UHF, and microwave signals travel in a(n) _____.

75. To increase transmission distances at VHF and above, special stations called are _____ used.

76. A microwave relay station contains a(n) _____ and a(n) _____ operating on different frequencies.

Check your work.

Complete List of Self-test and Reviewers in Communications Electronics

---

This is the Self-test in Chapter 8: Multiplexing from the book COMMUNICATIONS ELECTRONICS by Louis E. Frenzel. If you are looking for a reviewer in Communications Engineering this will definitely help. I can assure you that this will be a great help in reviewing the book in preparation for your Board Exam. Make sure to familiarize each and every questions to increase the chance of passing the ECE Board Exam.

Start Practice Exam Test Questions

Direction: Either Supply the missing word(s) in each statement  or Choose the letter that best answers each question.

1. Which statement is most correct?

• a. Multiplexing uses multiple channels to transmit multiple signals.
• b. Multiplexing uses multiple channels to transmit individual signals.
• c. Multiplexing uses a single channel to transmit multiple signals.
• d. Multiplexing uses a single channel to transmit a single signal.

2. Two common applications of multiplexing are _____.

3. The primary benefit of multiplexing is _____.

4. When multiplexing is used to transmit information, then a _____ must be used at the receiving end of the communications link.

5. The two types of multiplexing are _____.

6. In FDM, multiple signals share a common channel _____.

7. The multiple signals in an FDM system are used to modulate separate _____.

8. To combine the, multiple signals in FDM, a _____ is used.

9. The composite multiplex signal is normally used to _____ an RF carrier before being transmitted.

10. Most telemetry multiplex systems used_____ modulation.

11. Telemetry signals are first conditioned by _____ and/or _____ before modulating a sub carrier.

12. Telemetry signals typically frequency modulate a _____.

13. The key circuit in a demultiplexer is a(n) _____.

14. The best demodulator for telemetry work is the _____ discriminator.

15. In FDM telephone systems, _____ modulation is used.

16. The monaural signal in FM stereo multiplex is designated _____.

17. The four signals transmitted in FM stereo multiplex are _____.

18. The type of modulation used on the L – R channel is _____.

19. The SCA signals use _____ modulation.

20. In TDM, multiple signals share a channel by transmitting in different _____.

21. The process of sampling an analog signal at a high rate of speed is called _____.

22. The minimum sampling rate for a signal with a 7-kHz bandwidth this _____ kHz.

23. The basic switching element in a PAM multiplexer is a _____.

24. The name of the circuit used to recreate the clock pulses at the receiver in a PAM system is called a _____.

25. The multiplexer and demultiplexer are kept in step with one another by a(n) _____.

26. The time period during which all channels are sampled once is called a(n) _____.

27. A PAM signal is demodulated with a(n) _____.

28. A multiplexer is an electronic multi position _____.

29. The circuit that samples an analog signal in a PAM system is called a(n) _____.

30. In a PAM/FM system, the RF carrier modulation is _____.

31. A clock recovery circuit that tracks PAM frequency variations uses a(n) _____.

32. In PCM systems, analog signals are transmitted as _____.

33. Quantizer is another name for a(n) _____.

34. The standard audio sampling rate in a PCM telephone system is _____ kHz.

35. The standard word size in a PCM audio system is _____ bits.

36. The name of a widely used PCM telephone system is _____.

37. The process of emphasizing lower-level signals and de-emphasizing, higher-level signals is called _____.

38. An LSI circuit containing an ADC, DAC, compander, expander, and serial/parallel converters is called a(n) _____.

39. The main benefit of PCM over PAM, FM, and other modulation techniques is its immunity to _____.

40. A T-1 multiplexer has _____ and a total bit rate of _____ channels MHz.

Check your work.

Complete List of Self-test and Reviewers in Communications Electronics

---

This is the Self-test in Chapter 7: Communications Receivers from the book COMMUNICATIONS ELECTRONICS by Louis E. Frenzel. If you are looking for a reviewer in Communications Engineering this will definitely help. I can assure you that this will be a great help in reviewing the book in preparation for your Board Exam. Make sure to familiarize each and every questions to increase the chance of passing the ECE Board Exam.

Start Practice Exam Test Questions

Direction: Either Supply the missing word(s) in each statement  or Choose the letter that best answers each question.

1. The ability of a receiver to choose a desired signal frequency while rejecting closely adjacent signal frequencies is known as _____.

2. Decreasing the Q of a resonant circuit causes its bandwidth to _____.

3. Good selectivity usually means _____ (wide, narrow) bandwidth.

4. True or false. A tuned circuit can provide voltage gain.

5. S. Cascading tuned circuits cause the selectivity to _____ (increase, decrease).

6. If the selectivity of a tuned circuit is too sharp, the _____ of the received signal may be attenuated.

7. A tuned circuit has a Q of 100 at its resonant frequency of 500 kHz. Its bandwidth is _____ kHz.

8. A parallel LC tuned circuit has a coil of 3 H and a capacitance of 75 pF. The coil resistance is 10-Ω. The circuit bandwidth is _____ MHz.

9. A tuned circuit has a resonant frequency of 10 MHz and a bandwidth of 100 kHz. The upper and lower cutoff frequencies are f1 (upper) = _____ MHz, f2 (lower) = _____ MHz.

10. To achieve a bandwidth of 3 kHz at 4 MHz, a Q of_____ is required.

11. To narrow the bandwidth of a tuned circuit, the coil resistance must be _____ (increased, decreased).

12. A filter has a 6-dB bandwidth of 500 Hz and a 60-dB bandwidth of 1200 Hz. The shape factor is _____.

13. The greater the gain of the receiver, the better its _____.

14. A receiver that uses only amplifiers and a detector is known as a(n) _____ receiver.

15. A receiver that uses a mixer to convert the received signal to a lower frequency is called a(n) _____.

16. The acronym IF means _____.

17. Tuning a super heterodyne is done by varying the frequency of its _____.

18. Most of the gain and selectivity in a superhet is obtained in the _____.

19. The _____ circuit in a receiver com compensates for a wide range of input signal levels.

20. The mixer output is usually the difference between the _____ frequency and the _____ frequency.

21. The AGC voltage controls the gain of the _____.

22. For best selectivity and stability, the IF should be

• a. High
• b. Medium
• c. Low

23. An interfering signal that is spaced from the desired signal by twice the IF is called a(n) _____.

24. A superhet has an input signal of 15 MHz. The LO is tuned to 18.5 MHz. The IF is _____ MHz.

25. Images are caused by the lack of _____ at the mixer input.

26. A desired signal at 27 MHz is mixed with an LO frequency of 27.5 MHz. The image frequency is _____ MHz.

27. True or false. The LO may be above or below the signal frequency.

28. The main feature of a dual-conversion superhet is that it has two _____ circuits.

29. The image problem can be solved by proper choice of the _____.

30. A dual-conversion superhet has an input frequency of 50 MHz and LO frequencies of 59 MHz and 9.6 MHz. The two IFs are _____ MHz and _____ kHz.

31. List three sources of external noise.

32. List three main types of internal noise.

33. Noise from the sun and stars is called _____ noise.

34. Atmospheric noise comes primarily from _____.

35. List four sources of industrial noise.

36. The main source of internal noise is _____.

37. The SIN ratio is usually expressed in _____.

38. For best reception, the SIN ratio should be _____ (low, high).

39. Increasing the temperature of a component causes its noise power to _____.

40. Thermal noise is sometimes called _____ or _____ noise,

41. Narrowing the bandwidth of a circuit causes the noise level to _____.

42. The noise voltage produced across a 75- input resistance at a temperature of 25°C with a bandwidth of 15 MHz is _____ V.

43. Two types of. noise caused by tubes or transistors are _____ noise and _____ noise.

44. True or false. The noise at the output of a receiver will be less than the noise at the input.

45. True or false. The receiver amplifies noise as well as the signal.

46. The ratio of the SIN power at the input to the SIN power at the output is called the _____.

47. Noise temperature in degrees Kelvin is used to express the noise in a system at _____ (low, microwave) frequencies.

48. The noise figure of an amplifier is 2.6. The noise' temperature is _____ K.

49. The SINAD method considers the signal, noise, and _____ levels in a receiver.

50. Noise is more or a problem at _____ frequencies.

51. The stages of a receiver that contribute the most noise are the _____ and the _____.

52. True or false. An amplifier with a noise temperature of 170K is better than one with a rating of 235 K.

53. RF amplifiers provide initial _____ and _____ in a receiver but also add _____.

54. A low-noise transistor preferred at microwave frequencies is the _____ made of _____.

55. Most of the gain and selectivity in a superhet is obtained in the _____ amplifier.

56. The selectivity in an IF amplifier is usually produced by using _____ between stages.

57. The bandwidth of a double-tuned transformer depends upon the degree of _____ between primary and secondary windings.

58. In a double-tuned circuit, minimum band width is obtained with _____ coupling, maximum bandwidth with _____ coupling, and peak output with _____ or _____ coupling.

59. An IF amplifier that clips the positive and negative peaks .of a signal is called a(n) _____.

60. Clipping occurs in an amplifier because the transistor is driven by a high-level signal into _____.

61. The gain of a bipolar class A amplifier can be varied by changing the _____.

62. The overall RF-IF gain of a receiver is approximately _____ dB.

63. Using the amplitude of the incoming signal to control the gain of the receiver is known as _____.

64. AGC circuits vary the gain of the_____ amplifier.

65. The dc AGC control voltage is derived from a(n) _____ circuit connected to the _____ or _____ output.

66. Reverse AGC is where a signal amplitude increase causes a(n) _____ in the IF amplifier collector current.

67. Forward AGC uses a signal amplitude increase to _____ the collector current, which decreases the IF amplifier gain.

68. The AGC of a differential amplifier is produced by controlling the current produced by the _____ transistor.

69. In a dual-gate MOSFET IF amplifier, the dc AGC voltage is applied to the _____.

70. Another name for AGC in an AM receiver is _____.

71. In an AM receiver, the AGC voltage is derived from the _____.

72. Large input signals cause the gain of a receiver to be _____ by the AGC.

73. An AFC circuit corrects for frequency drift in the _____ circuit.

74. The AFC de control voltage is derived from the _____ circuit in a receiver.

75. A(n) _____ is used in an AFC circuit to vary the LO frequency.

76. A circuit that blocks the audio until a signal is received is called a(n) circuit.

77. Two types of signals used to operate the squelch circuit are _____.

78. In a CTCS system, a low-frequency _____ is used to trigger the _____ circuit.

79. A BFO is required to receive _____ and _____ signals.

80. What components or circuits in Fig. 7-27 determine the bandwidth of the receiver? (page 166-Frenzel)

81. As R1 is varied so that the voltage on the arm of the pot increases toward +9 V, how does the frequency of the local oscillator vary?

82. If there was no audio output from the speaker but you knew that a signal was present, what two controls would you check first?

83. What component provides most of the gain in this receiver?

84. Is the squelch signal or noise derived?

85. Does this receiver contain a BFO? Could it receive CW or SSB signals?

86. If the dc AGC voltage on pin 5 of U2 was decreased, what would happen to the gain of U2?

87. Where would you inject an audio signal to test the complete audio section of this receiver?

88. What frequency signal would you use to test the IF section of this receiver, and where would you connect it?

89. What component would be inoperable if C31 became shorted?

90. Explain how you would connect a digital counter to this receiver so that it would read the frequency of the signal to which it was tuned.

91. In an FM transceiver, the only shared circuitry is usually the _____.

92. In an SSB transceiver, the shared circuits are the _____ and the _____.

93. The circuit used to generate one or more stable frequencies for the transmitter and receiver is known as a(n) _____.

94. A basic circuit of a frequency synthesizer is a(n) _____.

95. The output frequency of a synthesizer is changed by varying the _____ of the divider between the VCO and phase detector.

96. A frequency synthesizer has a phase detector input reference of 10 kHz. The divide ratio is 286. The output frequency is _____ MHz. The frequency change increment is _____ kHz.

97. The PLL is often combined with _____ circuits to produce multiple frequencies.

98. What three frequencies does the synthesizer in a transceiver usually generate?

Check your work.

Complete List of Self-test and Reviewers in Communications Electronics

---

This is the Self-test in Chapter 6: Radio Transmitters from the book COMMUNICATIONS ELECTRONICS by Louis E. Frenzel. If you are looking for a reviewer in Communications Engineering this will definitely help. I can assure you that this will be a great help in reviewing the book in preparation for your Board Exam. Make sure to familiarize each and every questions to increase the chance of passing the ECE Board Exam.

Start Practice Exam Test Questions

Direction: Either Supply the missing word(s) in each statement  or Choose the letter that best answers each question.

1. The simplest transmitter is a(n) _____ circuit.

2. Information sent in the form of coded dots and dashes is called _____ transmission and is abbreviated _____.

3. Fixed-frequency or channel operation of a transmitter is obtained by using a(n) _____.

4. An amplifier that isolates the carrier oscillator from other transmitter amplifiers is known as a _____ amplifier.

5. Intermediate power amplifier stages in a transmitter are commonly referred to as _____.

6. The output RF power amplifier in a transmitter is sometimes called the _____.

7. Audio circuits that prevent excessive signal bandwidth and over modulation are called _____. circuits.

8. In an PM transmitter, special amplifiers called _____ are used to increase the carrier frequency and deviation to the desired output values.

9. In an SSB transmitter, the final output frequency is usually produced by a(n) _____ circuit before being amplified.

10. The power level of SSB signals must be increased by _____ amplifiers to prevent distortion.

11. Frequency-modulated signals use _____ amplifiers for power amplification.

12. Linear power amplifiers are used to raise the power level of _____ and _____ signals.

13. A _____ power amplifier is used to increase the power level of an FM signal.

14. Linear power amplifiers operate class _____ and _____.

15. A Class A Transistor amplifier has an efficiency of 50 percent. The output power is 27W. The power dissipated in the transistor is _____ W.

16. Class A amplifiers conduct for _____ degrees of a sine wave input.

17. The cause of self-oscillation in a transistor RF amplifiers is _____.

18. Self-oscillation in an RF amplifier that does not occur at the tuned frequency of the amplifier is called _____.

19. Self-oscillation of an RF amplifier can be eliminated by the process of _____.

20. True or false. Elimination of self-oscillation can be accomplished with either a feedback inductor or a capacitor.

21. Combining a feedback capacitor with the internal capacitance of the transistor forms a(n) _____ circuit which is used to cancel the self-oscillation.

22. True or false. With no input, a class B amplifier does not conduct.

23. Class B RF power amplifiers normally used a(n) _____ configuration.

24. A class C amplifier conducts for approximately _____ degrees to _____ degrees of the input signal.

25. In a class C amplifier collector current flows in the form of _____.

26. In a class C amplifier, a complete sinusoidal output signal is produced by a(n) _____.

27. The efficiency of a class C amplifier is in the range of _____ to _____ percent.

28. The tuned circuit in the collector of a class C amplifier acts as a filter to eliminate _____.

29. A class C amplifier whose output tuned circuit resonates at some integer multiple of the input frequency is called a(n) _____.

30. Frequency multipliers with factors of 2, 3, 4, and 5 are cascaded. The input is 1.5 MHz. The output is _____ MHz.

31. A class C amplifier has a de supply voltage of 28 V and an average collector current of 1.8 A. The power input is _____ W.

32. Maximum power transfer occurs when the generator impedance _____ the load impedance.

33. A commonly used two-element (LC) circuit called a(n) _____ is widely used for impedance matching.

34. List the two popular types of three element (LC) matching networks.

35. Most impedance-matching networks are _____ filters, so they eliminate harmonies.

36. The main advantage of pi and T networks over the L network is that the circuit _____ can be chosen.

37. 37 True or false. Most impedance-matching networks are made adjustable (tunable).

38. Calculate the L network components to match a 3-Ω internal resistance in series with an internal inductance of 19 nH to a 72-Ω load impedance in parallel with a stray capacitance of 32 pF at a frequency of 18 MHz.

39. Calculate the components of an LCC T network to match a 4-Ω internal resistance to a 52-Ω load at 72 MHz. Assume a Q of 12.

40. A transformer has 6 turns on the primary and 18 turns on the secondary. If the generator (source) impedance is 50Ω, the load impedance should be _____ Ω.

41. A transformer must match a 200 generator a 50-Ω load. The turns ratio must be _____.

42. A single-winding transformer is known as a(n) _____.

43. A doughnut-shaped powdered-iron core widely used to make RF transformers and inductors is called a(n) _____.

44. An RF transformer with a 1:1 turns ratio called a(n) _____ is connected in Ii special way to provide 1:4 or 4:1 impedance matching.

45. Untuned RF transformers permit _____ operation over a wide frequency range.

46. The two techniques used in speech processing are _____ and _____.

47. Name the two primary purposes of speech processing.

48. A diode _____ circuit is frequently used to restrict voice signal amplitude.

49. Name the two main purposes of a low-pass filter in a speech-processing circuit.

50. Over modulation in an AM transmitter causes distortion and out-of-band operation which is referred to as _____.

51. Audio compression is achieved by controlling the _____ of an audio amplifier.

52. Audio compression is used to increase the average _____ in an AM or SSB signal.

53. _____ and _____ circuits are used in a speech compressor to create a dc feedback control signal.

54. The gain of a transistor can be controlled by varying the _____.

55. The process of adjusting the amplification of a signal based on its amplitude is known as _____.

56. In an audio compressor, do low-level signals receive more or less amplification?

57. True or false. Speech processing may be done on the RF signal or the audio signal.

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Complete List of Self-test and Reviewers in Communications Electronics

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