CEPT T CD 01-13 E-1986 Engineering Requirements for a Voice Plus Data System《语音和数据系统工程要求》.pdf

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1、CEPT T/CD*0 Z, and Z, shall be substituted by reference networks. Details of such reference networks together with values aRs and a, to be found in Section B (depending on national requirements). Balance to earth The balance to earth shall be greater than the limits shown in Appendix 3. It will be m

2、easured selectively. a,=P,-P,; a, in dB Insertion loss The insertion loss should be less than 0.5 dB between the voice interfaces al/bl and a2/b2 in the following frequency ranges. ZG (generator) Range = ZE (receiver) Pl 300 . 3,400 Hz 600 ohms -10 dBm 6 kHz 200 ohms 8 kHz 200 ohms 10 kHz 200 ohms 1

3、2 kHz f72 Hz 200 ohms + 10 dBm 16 kHz f80 Hz 200 ohms -27 . +22 dBm (775 mV) Measurement Set-up in Appendix 4. a, = P, - P,; a, in dB The value of insertion loss above 3.4 kHz and outside of the range from 12 kHz to 16 kHz is not specified. Interference signals The noise shall meet the following req

4、uirements at the voice input terminals to the telephone set or to the line circuits in the telephone exchange when data transmission is in progress. Measurement Set-up in Appendix 5. RV: O . 1,600 ohms . Psophometric weighted noise The average psophometric weighted (speech) noise should be less than

5、 -72 dBmp (0.2 mV). . Unweighted noise The unweighted noise shall be less than the indicated values. It will be measured with a bandwidth of 80 or 100 Hz. Frequency/kHz 3.4 . 8 . 16 . 240 Vm (Ohms) Iconverted to absolute leve -47 dBm -72 dBm -64 dBm -50 dBm -35 dBm A-2.1.5. Non litiear distortion A-

6、2.1.5.1. The inuence of the transmit level on insertion loss For each frequency component between 300 Hz and 3,400 Hz the value of the insertion loss should not deviate more than 0.2 dB from the nominal value, when the transmit power will be increased from -40 dBm to +3.5 dBm. O Edition of February

7、16, 1987 I CEPT T/CD*OL-L3*E 6 2326434 0003351 T W TfCD 01-13 E Page 12 A-2.1.5.2. Harmonic distortion The total harmonic distortion (dtJ is expressed by the following formula: 4 The term d, represents the relative value of the sinusoidal wave, d, represents the relative value of the second harmonic

8、 of the original sinusoidal wave, etc. The measurements should be carried out with a nominal transmit level of O dBm in the frequency band of The total harmonic distortion should be less than 0.01. The group delay distortion between both voice channel interfaces must not exceed a value of 10 ps in t

9、he range 300 to 3,400 Hz. The measurement should be carried out with a transmit level of O dBm. 300 Hz-3,400 Hz. A-2.1.5.3. Group delay distorsion A-2.1.6. Electrical conditions A-2.1.6.1. D.C. load Currents of up to 100 mA shall not change the transmission and the performance requirements specified

10、 in Chapters A-2 and A-3. A-2.1.6.2. Polarity independence The channel filters shall operate independently of the subscriber line polarity. The required transmission values are to be met irrespective of the polarity. The d.c. loop resistance of both FUs in tandem shaii not exceed a value of 20 ohms

11、at a loop current of 14 . 60 mA. A-2.1.6.3. D.C. resistance A-2.2. Data channel interface (see item A-1.7.) A-2.3. Line interface This interface is a 2-wire interface. The requirements of Recommendation T/CD 01-01 shall apply (for further study). The balance to earth requirements of the input transf

12、ormer, together with a measurement Set-up, are given in Appendix 6. A-3. PERFORMANCE REQUIREMENTS A-3.1. Data channel performance The performance of the data channel of a voice plus data system TU(S), FU(S), line FU inclusion of such a technique is only justified if an improvement is required. Study

13、 of the behavior of errors (biist or single errors) is required before a particular method can be recommended. Remark: If this technique is used in combination with an ARQ technique it will increase the throughput soiisiderably. Eursts of errors are corrected by “ARQ”, and correction of single error

14、s will reduce the nuinber of retransmissions. O Edition of February 16, 1987 CEPT T/CD*OL-L3*E b W 2326414 0003363 b T/CD O1 -1 3 E Page 24 Data out Data- in Scrambler Descrambler Data out Input signal O O O O 1 1 1 1 1 1 1 1 O O O O O O O ABCD 1111 o111 O011 O001 1000 1100 1110 o111 1011 1101 O110

15、O011 1001 1100 O110 1011 O101 1010 1101 VWXYZ 1 11 111 1111 o1111 O0111 O0011 10001 11000 11100 O1110 10111 11011 O1101 O0110 10011 11001 O1100 10110 O O O O 1 error 1 1 1 1 1 1 1 O O O 0011110 0001110 0000110 1100010 1101001 0010101 110101ox 11 1 o 1 o ox 0011011 0001101 1100111 1110010 0011000 110

16、1100 -b o o 1 o o o ox x = changing of the output by more than a single edge per bit period is an indication for the occurrence of a bit error. bit period 19.2 kbit/s , low bitrate period fir- I input signal scrambler I I I X X X Output signal descrambler after a single transmission error Figure AP8

17、-1 (T/CD 01-13). Edition of February 16, 1987 CEPT T/CD*OL-l3*E 8b 2326434 0003364 8 I T/CD O1 -1 3 E Page 25 l 2. Exawiple of the localisation of thejrst bit hi error for 9,600 bit/s Figure AP8-2 (T/CD 01-13) = transmitted signal Figure AP8-3 (T/CD 01-13) = received signal with errors (case 1) Figu

18、re AP8-4 (T/CD 01-13) = received signal with errors (case 2) Figure AP8-2 (T/CD 01-13). output signal descrambler 1- x t X X t low bitrate timing Figure AP8-3 (T/CD 01-13). O Criterium for an error is an edge in the middle of a low bit rate period. O Location of the first bit in error If there is no

19、 edge in the third low bit rate period the last bit of O is affected (see Figure AP8-3 (T/CD 01-13). If there is an edge in the O (the third low bit rate period) the first bit is affected (see Figure AP8-4 (T/CD 01-13). output signal descrambler t t multiplication t t transmission error t low bitrat

20、e timing Figure AP8-4 (T/CD 01-13). Edition of February 16, 1987 t CEPT T/CD*OL-13*E b W 232b414 0003365 T W T/CD O1 -13 E Page 26 Appendix 9 Forward error correction for 2.4 kbit/s Figure AP9-1 (T/CD 01-13) shows a simplified block diagram for the TU(S) including FU(S) and the additional components

21、 for dividing of the signalling rate on the line and the forward error correction. FU) + TU(S) Additional components I Il TD scrambler 2,4 kbit/s 1 2,4 kbit/s Rx / rJ 19,2 kbit/s “ 234 - 2,4 kbit/s 1 II e m 2,4 kbit/s . 2,4 kbits I I - - ,I. Figure AP9-1 (T/CD 01-13). The forward error correction us

22、es a majority decision of 5 to 3, Le. if 1 bit error at 19.2 kbit/s occurs and will be increased by the descrambler in the TU(S) to 3 bit errors, this situation wiil be corrected. Figure AP9-2 (T/CD 01-13) gives an example of 2 bits of a 2.4 kbit/s data stream, which are disturbed. This signal wiil

23、be transmitted to the shift register with 19.2 kbit/s. After the comparator the 2 bits are correct again. “I”- - Bit 2 = “O Al, -I- , , Treshold “O” Figure AP9-2 (T/CD 01-13). Edition of February 16, 1987 CEPT T/CD*OL-L3*E 6 2326434 0003366 3 T/CD O1 -13 E Page 27 Appendix 1 O Electromagnetic compat

24、ibility (provisional values; submitted by the Nordic Countries) 1. INTRODUCTION In an electromagnetically quiescent environment only thermal noise would impose limitations on the attainable signal-to-noise ratio in communication. In reality the electrical activity of the atmosphere and the activitie

25、s of man give rise to disturbance factors of continuous and transient nature. In order to ensure that communication equipment performs satisfactorily in its electromagnetic environment, i.e. possesses adequate Electro Magnetic Compatibility (EMC) properties, four conditions must be satisfied. - The

26、electromagnetic environment on the installation site must be known. - Severities of testing must be stated which ensure that the equipment has sufficient immunity to the disturban- - Limits must be imposed on the electromagnetic emission from the equipment in order to prevent impairment - Methods of

27、 testing must be prescribed by means of which it may be ascertained whether the equipment ces occurring in its environment. of the proper function of other equipment or systems. complies with the requirements. - 2. ENVIRONMENTAL CONDITIONS The transmission unit and fiter units of the voice plus data

28、 system are installed on subscribers premises (subscriber side) as well as on switching centers (exchange side). The electromagnetic environmental conditions are different on these locations. Subscribers premises exhibit particularly varied environments being in urban or rural domestic areas or in a

29、reas of concentrated industry. It is favourable to operate with one version of equipment regarding EMC performance. Expecting that a sizeable fraction of voice + data systems are installed on industrial sites-even switching centers (PABX) may be located on such sites-the present EMC specification sh

30、all be based upon the electromagnetic conditions in an industrial environment. The electromagnetic environment is characterized by a number of parameters and their severities. Only para- meters which are important for the performance are included, the parameters are treated as independent factors, a

31、nd the severities stated for each parameter define levels of exposure which are rarely exceeded i. These “maximum” levels of exposure are designated characteristic severities in the tables below. 3. EMC SPECIFICATIONS. IMMUNITY 2 Immunity to every conceivable disturbance irrespective of its severity

32、 leads to overspecification. Hence, the immunity tests are graded taking the probability of occurrence of the severities into account. It is recommended that tests are made according to the following graded performance requirements. In order of increasing exposures the performance requirements are:

33、- Normal peiformance means that all specified performance requirements shali be fulfilled. The severity of testing is identical to the characteristic severity of the environment knowing that more severe conditions may occur in practice. - Intermittent Jimction means functional failure of short durat

34、ion. Automatic recovery to normal performance is required following cease of exposure unless otherwise specified. Recalling the statistical nature of the environmental conditions it is clear that intermittent function must be expected and accepted in few cases. - Cease of Jitnction means irreversibl

35、e functional failure. Equipment or components may suffer permanent breakdown. Any damage or permanent malfunction must be confined to the exposed parts of the equipment The tables below state the environmental parameters arranged according to coupling path, their characteristic severities, the grade

36、d severities of testing, reference to test methods, remarks, and reference to related national or international standards. 31. Edition of February 16, 1987 CEPT T/CD*OL-L3*E 6 m 2326434 0003367 3 m T/CD O1 -13 E Page 28 4. EMC SPECIFICATIONS. EMISSION 4 Emission from equipment must be limited in ord

37、er to - comply with national radio frequency interference regulations - conserve the environmental conditions on which immunity requirements are based. In both cases the limits depend on the general character of the installation site, being e.g. a dominantly domestic area or an area of industrial ac

38、tivity, depending on typical neighbour-to-neighbour distances and to the background noise level of the site. The more severe limits apply to installation in domestic areas. The voice plus data system must comply with these limits since a large proportion of the systems will be used in such areas. Th

39、e tables below state the emission limits for the important parameters, refer to a test method, and refer to related standards. These references apply to test methods, not to limits. 8 Edition of February 16, 1987 i CEPT T/CD*OL-L3*E 6 = 2326434 O003368 5 H TE-112 T/CD O1 -1 3 E Page 29 (a: Only appl

40、icable in N and S Immunity requirements, conducted interference 2 SIGNAL LINE TERMINALS - Unit Environmental parameter Severities of testing Test I Remarks No. Charact. severity 10; 500 100; 1M - 50 230; 650 (b - 600; 0.5 Ref. S Interm. func. Normal perf. 10 100 1x60 Cease of func. - V ohm S - V - V

41、 ohm S 500 1M 1 x 10 TE 18 (DK) DC common mode 16 Y3 Hz (a common mode 50 Hz common mode Amplitude Impedance Duration Amplitude Amplitude (ms) Impedance Duration TE-l/l 50 100 650 200 2 x 0.5/0.5 CCIT KY CCITT K20 TE 25 (DK) 230 600; 10 1 x900 230 600; 10 1 x 900 Vl.2 s and 900 V/.35 s is accepted i

42、n 50 Hz diff. mode Amplitude (rms) Impedance Dur at i on V ohm S 230 - 600 TE 17 (DK) Audio frequency common mode Frequency Amplitude (ms) kHz V 0.05 - 1 - 20 50 - 1.5 - 0.5 0.05 - 1 - 20 50 - 1.5 - 0.5 TE-115 TE 12 (DK) Radio frequency common mode Frequency Amplitude (rms) vlodulation MHz V - - kV

43、MHz - 0.02 - 1,000 5 - TE 05X (DK CISPRIE :SeCr) 27+2F 0.02 - 300 5 50 200; 100; 10 0.1; .05; .O1 -25; +25 10 x 100 -50; +50 10 x 40 - Schaffner I TE 08 (DK) 4 TE-213 -I 1 ms Per d - MHz V - - kV ns/ns kHz ms - - kV P/P - Duration Rate of occur Frequency Amplitude Modulatior (rm4 Amplitude (Pl TIIT,

44、 Rep. freq. Duration Repetition Amplitude (Pl TIIT2 Repetition 10 x 200 - 0.02 - 300 20 80% at 1 kHz 4 5/50 2.5 15 ms1300 ms 10 s (+) +10 s (-) 4 1/50 5 x (+)+5 x(-)/lO s Voltage interruption Radio frequency common mode Transient bursts common 5; 0.5 RF-LISN TE 06 (DK) CISPRIE (Secr) 27+2f Schaffner

45、 8s 436 15 03 NSG 225 IEC 801-4 Haefely PB4 gen. (9 0.5; 0.3; 0.2 T 5/50 5.0 15 ms/300 ms .lo s (+) + 10 s (-1 2 10/50 - - - 10; 2 Hybrid-gene- IEC 801-5 rat. 1/50 open circ. 8/20shortcirc. /“ I 5xy:;+5 x (-)Il0 s Edition of February 16, 1987 CEPT T/CD*OL-L3*E 6 2326434 0003370 3 m Normal perf. Inte

46、rm. func. Cease of func. - o to 40.5; 51 to 60 1x50 - - 100 7 - 50 - 50 10% at 1 kHz 100 150 - 1,000 - 1,000 80% at 1 kHz - 300 1,000 100 1/50 - 400 1/50 - - T/CD O1 -1 3 E Page 31 Immunity requirements, conducted interference 2 5 DC POWER SUPPLY TERMINALS (48 V) - Unit - V - V ms Per y I Environmen

47、tal parameter I Remarks Charact. severity 40.5 to 57 Ref. S CEET TE 20 (DK) T/TR 02-02 - TE-3/1 Variable DC- supply Voltage variation Voltage deviation Voltage Voltage Duration Rate of occur O to 40.5; 57 to 60 50 3 CEPT TE 21 (DK) T/TR 02-02 gen. NSG 204 impedance: 50 ohms in parailel with .3 ohms

48、+ 56 pH Audio frequency common & diff. mode Frequency Amplitude (ms) kHZ mV 0.025 - 0.1 - 1 - 20 200 - 200 - 7-7 0.025 - 0.1 - 200 - 200 - 800 - 800 - - 0.025 - 0.1 - 1-20 1 1-20 I CEPT TE 22 (DK) T/TR 02-02 30 - 30 7-7 I Radio frequency common & diff. mode Frequency Amplitude Modulation (rms) MHz m

49、V - 0.02 - 0.15 - 100 7 - 50 - 50 - 0.02 - 0.15 - I 0.02 - 0.15 - I TE- Generator impedance: 50 ohms in parallel with .3 ohms + 56pH CEPT TE 23 (DK) T/TR 02-02 - TE- Radio frequency bursts. Common & diff. mode Amplitude (Pl Frequency Repetition V MHz - 500 0.1 to 10 - Schaffner gen. NSG 505 Haefely P3 8s 436 15 03 (SI - 1 2 s/2 s Transients common & diff. mode Amplitude (Pl TIP, Rate of occur 200 5/00 3 CEPT TE 24 (DK) T/TR 02-02 NSG 504 Edition of February 16, 1987