Chapter 17: The Telephone Circuit - Review Notes

This is the summary notes of the important terms and concepts in Chapter 17 of the book "Electronic Communications System" by Wayne Tomasi. The notes are properly synchronized and concise for much better understanding of the book. Make sure to familiarize this review notes to increase the chance of passing the ECE Board Exam.

CHAPTER 17

THE TELEPHONE CIRCUIT

Items	Definitions	Terms
1	It comprised of two or more facilities, interconnected in tandem, to provide a transmission path between a source and a destination.	Telephone Circuit
2	The information transferred in a telephone circuit	Message
3	The circuit used in transferring information in a telephone circuit.	Message Circuit
4	The network bandwidth for a standard voice-band message channel.	4 kHz
5	Unused frequency bands located between information signals.	Guard Bands
6	Effective channel bandwidth for a voice-band message signal.	300 Hz to 3000 Hz
7	The only facility required by all voice-band circuits, as it is the means by which subscriber locations are connected to the local telephone company	Local Subscriber Loop
8	The primary cause of attenuation and phase distortion on a telephone circuit.	Two components found on local loops: Loading Coils Bridge Taps
9	The largest cable used in a local loop, usually 3600 pair of copper wire placed underground or in conduit.	Feeder Cable (F1)
10	A cross-connect point used to distribute the larger feeder cable into smaller distribution cables.	Serving Area Interface
11	A smaller version of a feeder cable containing less wire pairs.	Distribution Cable
12	A device that serves as the demarcation point between local telephone company responsibility and subscriber responsibility for telephone service.	Subscriber or Standard Network Interface (SNI)
13	The final length of cable pair that terminates at the SNI.	Drop Wire
14	That portion of the local loop that is strung between poles.	Aerial
15	The location where individual cable pairs within a distribution cable are separated and extended to the subscriber's location on a drop wire.	Distribution Cable and Drop Wire Cross Connect Point
16	Adding inductors periodically in series with the wire.	Loading
17	The inductor in loading technique.	Loading Coil
18	An irregularity frequently found in cables serving subscriber location.	Bridge Tap
19	A loss that allows signals to split and propagation down more than one wire introduced by bridge taps.	Bridging Loss
20	Weighting network introduced by AT & T to accomplish equal magnitude of noise signals.	C-Message Weighting
21	The most annoying frequency to human (i.e. the best frequency response).	1000 Hz
22	The basic yardstick used for making power measurements in communications.	Decibel (dB)
23	The optimum level of a test tone on a channel at some point in a communications system. It is used for voice circuits.	Transmission Level Point (TLP)
24	The ratio in dB of the power of a signal at that point to the power the same signal would be at 0 dBm transmission level point.	Transmission Level (TL)
25	The reference for TLP.	0 dBm
26	A parameter equivalent to TLP except it is used as a reference for data transmission.	Data Level Pint (DLP)
27	dBm reference to a zero transmission level point.	dBmO
28	dB reference value for noise reading.	reference noise (rn)
29	dB level of noise with respect to reference noise (- 90 dBm).	dBrn
30	Similar to dBrn except it is the dB value of noise with respect to reference noise using C-message weighting	dBrnc
31	Noise readings taken with a filter that has a flat frequency response from 30 Hz to 3 kHz	dBrn 3 kHz Flat
32	The amount of noise in dBrnc corrected to a 0 TLP	dBrncO
33	Identify when transitions occur in the data and whether that transition is from a 1 to a 0 or vice versa.	Three-Bit Code
34	Transmission parameters which include terminal impedance, in band and out of band signal power, test signal power and ground isolation.	Interface Parameters
35	Transmission parameters which includes noise measurements, frequency distortion, phase distortion, amplitude distortion and non linear distortion.	Facility Parameters
36	The difference in circuit gain experienced at a particular frequency with respect to the circuit gain of a reference frequency. Another names attenuation distortion: ·         Frequency Response, ·         Differential Gain ·         1004-Hz Deviation	Attenuation Distortion
37	An indirect method of evaluating the phase delay characteristics of a circuit.	Envelope Delay Distortion
38	It satisfies the minimum line conditioning requirements	Basic Voice-Band Channel
39	Another name for basic voice-band.	Basic 3002 Channel
40	Specifies the maximum limits for attenuation distortion and envelope delay distortion. Classifications of C-type: ·         C1 ·         C2 ·         C3 ·         C4 ·         C5	C-type Conditioning
41	Classification of C-type conditioning pertains to two point and multi point circuits.	C1 and C2
42	C-type conditioning used for access lines and trunk circuits associated with private switched networks.	C3
43	C-type conditioning pertains to two point and multi point circuits with a maximum of four stations	C4
44	C-type conditioning pertains to two point circuits only	C5
45	A relatively low-capacity switching machine where the subscribers are generally limited to stations within the same building or building complex.	Private Branch Exchange (PBX)
46	The frequency response of a transmission medium referenced to 1004 Hz test tone.	Attenuation Distortion
47	A requirement for error free data transmission.	Linear Phase vs. Frequency
48	The difference in phase shifts with respect to frequency that signals experience as they propagate through a transmission medium.	Delay Distortion
49	The time delay encountered by a signal as it propagates from source to a destination.	Propagation Time
50	The delay measured in angular units.	Phase Delay
51	The actual time required for a particular frequency to propagate from a source to a destination through a communications channel.	Absolute Phase Delay
52	The time required to propagate a change in an AM envelope through a transmission medium.	Envelope Delay
53	The phase difference at the different carrier frequencies.	Envelope Delay Distortion
54	It sets the minimum requirements for signal to noise ratio and nonlinear distortion.	D-Type Line Conditioning
55	The data transmission rate when D type conditioning is mandatory.	9600 bps
56	Telephone industry standard test tone frequency	1004 Hz
57	Measurement that determine the average weighted rms noise power.	C-message Noise Measurement
58	A communications term that indicates the presence of a signal power comparable to the power of an actual message transmission.	Loaded
59	Characterized by high amplitude peaks of short duration having an approximate flat frequency spectrum	Impulse Noise
60	A sudden, random change in the gain of a circuit resulting in a temporary change in the signal level.	Gain Hit
61	A decrease in circuit gain of more than 12 dB lasting longer than 4 ms.	Dropout
62	A sudden, random changes in the phase of a signal.	Phase Hits (Slips)
63	A form of incidental phase modulation – a continuous, uncontrolled variation in the zero crossings of a signal.	Phase Jitter
64	The presence of one or more continuous, unwanted tones within a message channel.	Single Frequency Interference
65	Unwanted tones within a message channel.	Spurious Tones
66	The frequency of the signal changes during transmission.	Frequency Shift
67	It occurs in coherent SSBSC systems when the received carrier is not reinserted with the exact phase relationship to the received signal as the transmit carrier possessed.	Phase Intercept Distortion
68	It occurs in coherent SSBSC systems when the received carrier is not reinserted with the exact phase relationship to the received signal as the transmit carrier possessed.	Phase Intercept Distortion
69	A four wire circuit an interface.	Hybrid Set
70	Another name for hybrid set.	Terminating Set
71	Any disturbance created in a communications channel by signals in other communications channels.	Crosstalk
72	Annoying and objectionable because the listener senses a real or fancied loss of privacy	Intelligible crosstalk
73	It does not violate privacy, although it can still be annoying.	Unintelligible crosstalk
74	A direct result of nonlinear amplification in analog communications system.	Nonlinear Crosstalk
75	Electromagnetic coupling between two or more physically isolated transmission media.	Coupling Crosstalk
76	Interference caused by inadequate control of the transfer characteristics or transmittance of networks.	Transmittance Crosstalk

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