ITU-T G 727 APP I-1991 Description of the Digital Test Sequences for the Verification of the G 727 5- 4- 3- and 2-bit Sample Embedded ADPCM Algorithm - Series G Transmission System.pdf
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1、STD-ITU-T RECMN G.727 APPEND I T-ENGL 1771 m 4Bb2571 Ob32343 171 m INTERNATIONAL TELECOM MUN ICATION UN ION ITU=T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU G.727 Appendix I Test vectors (03/9 I ) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS Digital transmission system
2、s - Terminal equipments - Coding of analogue signals by methods other than PCM Description of the digital test sequences for the verification of the G.727 5-, 4-, 3- and 2-bitlsample embedded ADPCM algorithm - STD-ITU-T RECMN G-727 APPEND I T-ENGL 1771 = 48b259L 0b323LI2 OZ8 D FOREWORD IT (Internati
3、onal Telecommunication Union) is the United Nations Specialized Agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of the ITU. The ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendat
4、ions on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Conference (WTSC), which meets every four years, establishes the topics for study by the IT-T Study Groups which, in their turn, produce Recommendations on these topics. The
5、 approval of Recommendations by the Members of the ITU-T is covered by the procedure laid down in WTSC Resolution No. 1. In some areas of information technology which fail within IT-Ts purview, the necessary standards are prepared on a collaborative basis with IS0 and IEC. INTELLECTUAL PROPERTY RIGH
6、TS The IT draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. The ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted
7、 by IT members or others outside of the Recommendation development process. As of the date of approval of this Recommendation, the ITU hadhad not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautione
8、d that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. O ITU 1997 Ali rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microf
9、ilm, without permission in writing from the ITU. STD*ITU-T RECMN 6.727 APPEND I T-ENGL 1991 M 48b2571 Ob32343 Tb4 DESCRIPTION OF THE DIGITAL TEST SEQUENCES FOR THE VERIFICATION OF THE G.727 5-, 4-, 3- AND 2-BIT/SAMPLE EMBEDDED ADPCM ALGORITHM 1 Introduction This technical report describes the test s
10、equences (vectors) for the embedded ADPCM algorithms of Recommendation G. 727. The test sequences are arranged in six separate diskettes, three for the p-law and three for the A-law: 1) 2) 3) Diskettes 1 and 2 contain the reset and the homing test sequences for the embedded ADPCM algorithms (5,2), (
11、5,3) and (5,4) for both the p-law and A-law respectively. Diskettes 3 and 4 contain the reset and the homing test sequences for the embedded ADPCM algorithms (4,2), (4,3) and (4,4) for both the p-law and A-law respectively. Diskettes 5 and 6 contain the reset and the homing test sequences for the em
12、bedded ADPCM algorithms (2,2), (3,2) and (3,3) for both the p-law and A-law respectively. The diskettes are of the 3% MS-DOS format. A READ.Ml3 file lists the contents of each diskette. 2 General description The verification testing procedure consists in applying an input sequence to an embedded ADP
13、CM implementation and verifying that the output sequence is the same sequence in the output file for the same test conditions (PCM coding law, type of input, initial state of the implementation). There are three types of input sequences. The first type consists of various sinusoidal PCM inputs that
14、are representative of the signals expected in normal operation. These are called “normal inputs“. A second group of input sequences is the set of “overload inputs“ that contain PCM signals of very large amplitudes. The third group is the set of ADPCM sequences that can exercise the algorithm in a ma
15、nner that is not possible with any PCM input sequence. They test the arithmetic and algorithmic performance of the ADPCM decoder by driving it to states that are unreachable by PCM signals under normal conditions. For example, these states may result from errors on the transmission line. These inter
16、mediate sequences will be denoted as “I-inputs“. The values (or samples) contained in a test file are given in ASCII hexadecimal representation with two hexadecimal characters per 8-bit value. In files with 5-bit ADPCM values, the three most significant bits are set to O. Files containing 4-bit ADPC
17、M values have the four most significant bit of each value set to O. Files that contain 3-bit ADPCM values have the five most significant bits of each word set to O. For files containing 2-bit ADPCM values, the six most significant bits are set to O. All PCM A-law inputs are in the format specified b
18、y Table ldG.711, Le. the even bits are inverted. Each line in any file contains up to 32 values (or 64 characters) and ends with a line feed character. Two more hexadecimal characters representing the result of a checksum computation over the entire file are appended to each file. This checksum is t
19、he remainder of the division of 255 of the sum of all sample values (two hexadecimal characters comprise a sample value) in the file. It has been noted that these diskettes do not always copy correctly using DISKCOPY due to the interaction of DISKCOPY with certain character sequences found in the te
20、st sequences. Either files should be copied individually using COPY, or XCOPY should be used instead of DISKCOPY. Recommendation G.727 - Appendix I - Test vectors description 1 STD-ITU-T RECMN G-727 APPEND I T-ENGL 1791 = 48b2571 0b323Lt4 7TO D Description PCM input word ADPCM word PCM output word I
21、 3 Test configurations Word format Identical to that of SP described in the sub-block COMPRESS of the synchronous coding adjuster (6.2.1 O/G. 727) As specified in the sub-block RECONST of the inverse adaptive quantizer (6.2.4/G.727) Identical to that of SP described in the sub-block COMPRESS (6.2.10
22、lG.727) Test sequences are derived for the two configurations shown in Figures 1 and 2, respectively, The configuration of Figure 1 is the arrangement with the encoder transmitting to the decoder for error- free operation. The configuration of Figure 2 allows for input ADPCM words that would not nor
23、mally emanate from an encoder and a PCM input word. The word formats of the various sequences are detailed in Table 1. PCM Output sequence PCM Input sequence S SD 4 I or I, ADPCM Ouput sequence T1527200-97 Figure 1 - Encoder and decoder configuration ADPCM Input sequence PCM output sequence i or I,
24、Decoder SD T15272 10-97 Figure 2 - Decoder only configuration I I I 4 Test com binations The initiai state of the implementation may be either the reset state of the algorithm defined in Table 2 or a well-defined initial state that follows the application of an initialization (or homing) sequence. A
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