1、- STD-SMPTE 252M-ENGL L79b 83571.103 0002b3b TTB SMPTE STANDARD ANWSMPTE 252M-1996 Revision of ANSIISMPTE 252M-1991 for Television Analog Recording - 1/2-in Type M-2 - Pulse Code Modulation Audio 1 Scope This standard specifies the pulse code modulation (PCM) audio mode of encoding and recording sys
2、tem utilizing a 1/2-in type M-2 helical-scan video tape recorder operating with video signals having a typical scanning structure of 525 lines, 59.94 fields/s, 2:l interlace, and the cassettes specified in ANSIISMPTE 250M. 2 Normative references The following documents contain provisions which, thro
3、ugh reference in this text, constitute provisions of this standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent edition
4、 of the standards indicated below. ANSVSMPTE 249M-1996, Television Analog Record- ing - 1/2-in Type M-2 - Records ANWSMPTE 250M-1996, Television Analog Record- ing - 1/2-in Type M-2 - Tapes and Cassettes SMPTE RP 155-1 995, Audio Levels for Digital Audio Records on Digital Television Tape Recorders
5、3 Recording location The PCM audio signal is recorded on tape regions PD, PE, and PF, located on the video track as shown in ANSVSMPTE 249M. Since the recording area for longitudinal audio CH-1 is allocated for the PCM recording, longitudinal audio recording can be accom- plished only on one channel
6、 (CH-2). Page 1 of 10 pages 4 Audio signal recording The recording of PCM audio signals in each of two channels is accomplished by using the luminance and chrominance heads provided for video signal record- ing as shown in figure 1. The recording is accomplished beyond the overlap area on the tape p
7、roduced by making the wrap angle on the scanner more than 180. Direct recording of time compressed digital modulation is employed. 4.1 Source coding The source data consists of the audio data and the ID (identification) data. 4.1.1 Audio data specifications Number of channels: Two channels (CH-5 and
8、 CH-6). Reference level: The input required to give -20 dB full-scale at ND converter (at 1 kHz) shall be the reference level and its digital value shall be as speci- fied in SMPTE RP 155. Track allocation: CH-5 shall be recorded by the luminance head. CH-6 shall be recorded by the chrominance head.
9、 Stereo mode: CH-5 is the left channel. CH-6 is the right channel. 4.1.2 Audio data coding -Sampling frequency: 48 kHz (synchronous with video signal) - Sampling order: - Quantization: 16-bit linear -Coding: Twos complement binary code CH-5, CH-6 simultaneous CAUTION NOTICE This Standard may be revi
10、sed or withdrawn at any time. The procedures of the Standard Developer require that action be taken to reaffirm, revise, or withdraw this standard no later than five years from the date of publication. Purchasers of standards may receive current information on all standards by calling or I writing t
11、he Standard Developer. Printed in USA. Copyngh O 1996 by THE SOCIETY OF L American Nalonal Standard MOTION PICTURE ANDTELEVISION ENGINEERS 595 W. Hatisdale Ave., White Plains, NY 1DMn (914)761-1100 U Approved November 29,1996 STD*SMPTE 252M-ENGL 377b = 8357403 0002b37 734 ANCVCMPTE 2521111-1996 I Oc
12、- DIA 4- I . output / El 4 4 - Play back Demodulator CH6 - Error I I corrector I Figure 1 - Block diagram of PCM audio recording system 4.1.3 ID data coding - Data capacity: 6-byte or 8-byte/field as shown in tables 1 and 2. - Coding: NRZ 4.1.4 Source data arrangement The source data arrangement wit
13、hin one audio field period is shown by tables 1 and 2. The 16-bit audio samples shown in tables 1 and 2 are each divided into upper and lower 8-bit samples which are arranged in an order starting from suffix O. However, in this five audio field periodic sequence, the data D 800U and D 800L are avail
14、able in audio fields O, 1, 2, and 3, but the data in audio field 4 shall be replaced by ID6 and ID7. 4.1.5 ID data specification The ID data region is available for the user, and its contents are shown in figure 2 and tables 1 and 2. 4.2 Signal processing The 800 or 801 audio data samples per field
15、are divided into 67 blocks, and the block sync signal (SYNC), block address signal (ADDRESS), block address error detecting code (CRCC), and the error correction code (ECC2 and ECCl) are added to each block. The signal format is shown in figure 3 where the recording order for each data sample is MSB
16、 first. 4.2.1 PCM signal construction The PCM signal construction is shown in figure 4. - Preamble area: - Length: one horizontal line (63.5 p). - Content: a single frequency signal of 5.0625 MHz (basic) NOTE - A basic dimension is a fundamental dimen sion to which no tolerance is applicable. Page 2
17、 of 10 pages STD-SMPTE 252M-ENGL L99b = 8357L101 0002b38 870 DOU DOL ANSVSMPTE 252M-1996 D2U D4U D6U D8U D62U D64U D66U D1U D3U D59U D61U D63U D65U D2L D4L D6L D8L D62L D64L D66L DIL D3L D59L D61L D63L D65L Table 1 - Source data arrangement for fields O, 1, 2 and 3 Data Symbol Block INumber/ #O I #I
18、 I #2 1 #3 I #4 1 #31 1 #32 1 #33 I #34 1 #35 I #63 I #64 I #65 I #66 I D 67U D 69U D 71U D 73U D 75U D129U D131U D133U D 68U D 70U D126U D128U D130U D132U D737U D739U D741U D743 D745U D799U ID O ID 4 D738U D740U D796U D798U ID 6 ID 2 D737L D739L D741L D743L D745L D799L ID 1 ID 5 D738L D740L D796L D
19、798L ID 7 ID 3 Table 2 - Source data arrangement for field 4 I #O I #1 1 #2 1 #3 1 #4 I #31 1 #32 i #33 1 #34 I #35 1 #63 I #64 1 #65 1 #66 I Block Number Phase continuity to the beginning of the sync block shall be established. - Postamble area: - Length: one horizontal line (63.5 ps). - Content: a
20、 single frequency signal of 5.0625 MHz (basic) Phase continuity to the end of the data block shall be established. - SYNC: Specified in 4.2.4. - ADDRESS: Started from “00“ by the sequential address for the identification of each of the 67 blocks. - CRCC: CRCC is used for block ADDRESS error detectio
21、n; this detected error pointer is referred to data error correction. The error detection method is based upon a CRC code containing 8 bits and its generator polynominal G1 (x) is as follows: - DATA: Data shall be arranged in the order shown in tables 1 and 2 and figure 3. - ECC2, ECC1: Specified in
22、4.2.2. - Transmission data rate: 11.57 Mbps per channel. 4.2.2 Error correction codes The error detection and correction system (ECC) shall be based on the Reed-Solomon code which contains the elements of Galois field 28, and its generator polyno- minal G2(x) and primitive polynominal G3(x) are give
23、n by: 3 G2(x) = ( x - ai ) =O G(x)= X8+X4+x3+X2+ 1 The generation scheme of error correction codes ECC1 and ECC2 is shown in figure 5. Page 3 of lapages STD-SMPTE 252M-ENGL 1776 8357qOL 0002b37 707 O 1 O Not specified 3 1 1 O ANCVSMPTE 2521-1 996 MSB I I I I I I Bit position I 1 1 I I I I l I LSB Re
24、served Region: I Field Address Bo Bi Ba 83 B4 B5 Bs B7 I Figure 2 - ID data content and reserved region for field address Page 4 oi 10 pages STD-SUPTE 252M-ENGL L77b = 8357qOL 0002b40 427 SYNC I SYNC 1 SYNC I SYNC 1 SYNC Recording Direction SYNC SYNC SYNC ANSVSMPTE 2521111-1996 ECC2 ECCl Block Addre
25、ss D 7371. D 799L D 741L ID5 D?WL * ID3 ECC2o ECC2i ECC22 ECC233 ECC23 ECC2eb ECC2m EGG10 ECCli ECC12 ECCls ECClS ECC166 ECClbS - - - c- Pre-amble I l I I I - I Post- * amble 6-0 B-1 B-2 045 - M LM LM S ss ss LM L 9 ss I ks ei 0 BE 0B 6s SYNC ADDRESS CRCC DATA E022 ECC CRCC I CRCC7 CRCC I CRCC 1 I C
26、RCC I CRCC I I CRCC I CRCC I Figure 3 - PCM signal format NOTE - 1 symbol = 8 bits. Figure 4 - PCM signal construction Page 5 of 10 pages STD-SMPTE 252M-ENGL 177b M 8357901 0002bllL 3b5 #I 2 3 , 5 8 7 8 0 10 1, D*TA 14 15 16 1, 1s 1s 20 2, u 23 24 25 ECC* ,7 a 20 Etc, 32 ANCVCMPTE 2521111-1996 O 0 .
27、 0 0. . . o o. . . . .o . .o o . . n . .0 0 O . . .O . O . . O o o “O . . . . D ri. BLOCK NUMBER - 406-.10 1520 25 30 35 4 45 50 55 60 85. Positive Negative Positive polarity Select group A Select group B Note: EGG1 ; OF (2% (32, 28, 5) O ECCP;GF (28, 24. 5) Positive Neaative Negative polarity Figur
28、e 5 - Error correction format Select group B Select group A 4.2.3 Channel coding The channel code shall conform to the 8-1 4 modula- tion method (see figure 6 and tables 3 and 5). This method is based on an algorithm where the DC com- ponent is minimized when the 8-bit data is converted to a 14-bit
29、code. The data converted by the 8-14 modulation method shall be further transformed by NRZI conversion process before it is recorded. Table 3 - Selection of modulation code 1 Preceding DSV Preceding polarity IrnodUg;?:de Dala I Zero - BB BC BD BE BF Co c1 c2 c3 c4 c5 c6 C? c8 c9 CA CB cc CD CE CF Do
30、 D1 D2 03 04 D5 D6 D7 08 09 DA DB DC DD DE DF EO El E2 3 E4 E5 E6 E7 E8 Eg - GrOUD A (Positive) Code o1001001001010 00101010010100 00100101010100 001 00101001010 10101001010010 1010101001oooo 10101o00100100 10100100101oO0 101001m10100 100101ooo10010 10010010101ooo 1001001ooo1010 1o001010100100 1o001
31、010010010 1oooo100101010 01010100101m 010101oO010100 01O01010101ooo 0100101o0o1010 01o00101010100 Olo00101 00101 o 1o001m1ooM) 1m1m1o00 10010101010010 10010100101010 10101001001oO0 10010101 001Ooo 10010100100100 100100100101M) 11001010100 1ooo1001001010 o1001010010100 10101010101010 00100000010000 O
32、0010000001000 00101oooo1m 001 ooool ooool o m1010010000 0010101m100 00101001oooo10 001oooo1010100 o0O10101m10 oO01oooo101010 00100loM)o1oO0 001oO01m100 ooo101oO01m - CDS 2 2 2 2 2 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 2 2 4 4 4 4 4 4 4 2 O O O O O O O O O O O O O O - - Group B (Negative) bd m101o00100
33、10 o0O10010101m ooo1001m1010 oooo1001010100 oooo1001001010 o00101 00101010 10101010101o0o 1010101o0O1010 101ooo10101010 101001OoO1m 1001o001001ooo 0101001oO01OOO 01001001001ooo 01001o0O100100 00101001oO0100 00100101001m 001001ooo10010 001Ooo10010100 o00100101 O01 00 o0010010010010 OOOlOoo1001010 001
34、01001010010 10101010010100 M)101001001o0O ooo10010010100 10100101010100 10100101001010 01010101010100 01010101001010 01010010101010 00101010101010 001001001001w oooo1m1m 00100000010000 oooo1000000100 ooo11OOO 00101m1oooo 001oooo1m10 oooo101001m 0010101oooo100 00101M)1oooo10 001001010100 oO010101oooo
35、10 o0010000101010 001001ooooio0o 601ooo10000100 o00101o001ooOo - CDI -4 -4 -4 -4 -4 -2 -2 -2 -2 -2 -2 -2 -2 -2 -2 -2 -2 -2 -2 -2 -2 -2 -2 -4 -4 -2 -2 -2 -2 -2 -2 -2 -4 O O O O O O O O O O O O O O - - EC I F: JH F5 IZ IF, FA Code ICDS Code ICDS Annex A (informative) Bibliography ANSVSMPTE 251 M-1996, Television Analog Recording - 1/2-in Type M-2 - Electrical Parameters of Video, Audio, Time and Control Code and Tracking Control SMPTE RP 158-1991 (Rl995), Basic System and Transport Geometry Parameters for 112-in Type M-2 Format Page 10 of 10 pages
