1、STD.TIA TIA/EIA-OZ.BABC-ENGL 1qqq 6057943 0000646 568 H ANSI/TIA/EIA-102.BABC-1999 Approved: March 16, 1999 TIA/EIA STANDARD Project 25 Vocoder Reference Test TIA/EIA-102 .BABC (upgrade and Revision of TIAIEIAIIS-102.BABC) APRIL 1999 TELECOMMUNICATIONS INDUSTRY ASSOCIATION Elretronic Industrie Allia
2、nce NOTICE TIAEIA Engineering Standards and Publications are designed to serve the public interest through eliminating misunderstandings between manufacturers and purchasers, facilitating interchangeability and improvement of products, and assisting the purchaser in selecting and obtaining with mini
3、mum delay the proper product for his particular need. Existence of such Standards and Publications shall not in any respect preclude any member or nonmember of TIAEIA from manufacturing or selling products not conforming to such Standards and Publications, nor shall the existence of such Standards a
4、nd Publications preclude their voluntary use by those other than TIAEIA members, whether the standard is to be used either domestically or internationally. Standards and Publications are adopted by TIAEIA in accordance with the American National Standards Institute (ANSI) patent policy. By such acti
5、on, TIMIA does not assume any liability to any patent owner, nor does it assume any obligation whatever to parties adopting the Standard or Publication. This Standard does not purport to address all safety problems associated with its use or all applicable regulatory requirements. It is the responsi
6、bility of the user of this Standard to establish appropriate safety and health practices and to determine the applicability of regulatory limitations before its use. (From Standards Proposal No. 4338, formulated under the cognizance of the TIA WG4 Vocoder Working Group of the TR-8 Committee on Mobil
7、e & Personal Private Radio Standards). Published by OTELECOMMUNICATIONS INDUSTRY ASSOCIATION 1999 Standards and Technology Department 2500 Wilson Boulevard Arlington, VA 2220 I PRICE: Please refer to current Catalog of EIA ELECTRONIC INDUSTRIES ALLIANCE STANDARDS and ENGINEERING PUBLICATIONS or call
8、 Global Engineering Documents, USA and Canada (1-800-854- 7179) International (303-397-7956) All rights reserved Printed in U.S.A. Foreword: This Vocoder Standard TINEIA-I 02. BABC, titled Project 25 Vocoder Reference Test, has been developed with inputs from the Project 25 Interface Committee (APIC
9、), the APIC Vocoder Task Group, and TIA Industry Members. This Standard will be maintained by the TR-8.4 Committee under the sponsorship of TIA TR-8. This Standard describes a vocoder reference test for codecs meeting the Project 25 requirements. For system implementations, such as Conventional, Tru
10、nking, Encryption, etc. this document provides only the appropriate test references to ensure vocoder compatibility, rather than the requisite specification detail for such implementations. For information on specific system implementations, as they are developed, the reader is referred to I for a P
11、roject 25 Overview, a General System Model, other appropriate standards, a Glossary, and a statement of Requirements. The readers attention is called to the possibility that compliance with this Standard may require the use of one or more inventions covered by patent rights. By publication of this S
12、tandard, no position is taken with respect to the validity of those claims or any patent rights in connection therewith. The patent holders so far identified have, however, filed statements of willingness to grant licenses under those rights on reasonable and nondiscriminatory terms and conditions t
13、o applicants desiring to obtain such licenses. Details may be obtained from the publisher. i 1 Scope . 1 2 Overview . 3 3 A25VCTS Operation Manual . 4 3.1 Run Loopback Test . 4 3.2 Run Type Approval Test . 6 Run All Decoder Tests 7 Run Individual Decoder Tests . 7 Test 1 - Decoder Frequency Response
14、 . 8 Test 2 - Medium Pitch, High Amplitude 8 Test 3 - Medium Pitch, Medium Amplitude . 9 Test 4 - Medium Pitch, Low Amplitude . 9 Test 5 - High Pitch . 9 Test 6 - Low Pitch 9 Test 7 - Correctable Bit Errors 10 Test 8 - Frame Repeat Errors . 10 Test 9 - Delay . 10 Test A - Idle Channel Noise 10 Test
15、B - Crosstalk . 11 Test C - Out-of-Band Frequency Response 11 Run All Encoder Tests 11 Run Individual Encoder Tests . 11 3.2.1 3.2.2 3.2.2.1 3.2.2.2 3.2.2.3 3.2.2.4 3.2.2.5 3.2.2.6 3.2.2.7 3.2.2.8 3.2.2.9 3.2.2.1 O 3.2.2.1 1 3.2.2.1 2 3.2.3 3.2.4 4 4.1 4.2 5 5.1 5.2 3.2.4.1 Test 1 . Encoder Frequenc
16、y Response . 12 3.2.4.2 Test 2 . Medium Pitch. High Amplitude 13 3.2.4.3 Test 3 - Medium Pitch, Medium Amplitude . 13 3.2.4.4 Test 4 - Medium Pitch, Low Amplitude . 13 3.2.4.5 Test 5 - High Pitch . 14 3.2.4.6 Test 6 - Low Pitch 14 3.2.4.7 Test 7 - VoicedlUnvoiced Accuracy 14 3.2.4.8 Test 8 - Out of
17、Band Energy . 14 3.2.4.9 Test 9 - Delay . 15 3.2.4.1 O Test A - Idle Channel Noise 15 3.2.4.11 Test B-CrosstalkTest . 15 3.2.4.12 Test C - Out-of-Band Frequency Response 16 Test Computer Hardware and IO Circuitry . 17 IBM PC Compatible Computer 17 The DSP cards and the 110 Interface Circuitry 17 Tes
18、t Computer S0fh.a. . 18 Loopback Test . 18 Decoder Type Approval Tests 19 5.2.1 5.2.2 5.2.3 5.2.4 5.2.5 5.2.6 Test 1 . Decoder Frequency Response . 19 Test 2-8 . Measure Decoder Distortion and Pitch 20 Test 9 - Delay . 21 Test A - Idle Channel Noise 22 Test B - Crosstalk . 22 Test C - Out-of-Band Fr
19、equency Response 23 5.3 Encoder Type Approval Tests 23 . III . 5.3.1 5.3.2 5.3.3 5.3.4 5.3.5 5.3.6 Test 1 . Encoder Frequency Response . 23 Test 2-8 . Measure Encoder Distortion and Pitch 24 Test 9 - Delay . 25 Test A - Idle Channel Noise 25 Test 6 - Crosstalk . 26 Test C - Out-of-Band Frequency Res
20、ponse 27 6 Objective Performance Requirements 28 Decoder Type Approval Tests . 30 7 References 35 6.1 Loopback Test . 28 6.2 6.3 Encoder Type Approval Tests . 34 TIAEIA-102.BABC 1 Scope This document specifies one method that may be employed to test that implementations of TIAEIA-l02. BABA compatibl
21、e speech codecs meet recommended minimum performance requirements. This speech codec is the Improved Multi-Band Excitation (IMBETM ) system described in 2. The IMBE speech codec is used to digitally encode the speech signal at 4400 bps or decode the speech signal back to analog audio. Forward error
22、correcting codes (FEC) are added to this to increase the signaling rate to 7200 bps. Most of the tests in this document are for the speech codec, and some of the tests verify the conformance of the FEC. All of the tests use an interface operating with the combined FEClcodec signal at 7200 bps. The n
23、eed for this procedure arises from the fact that implementations of speech coders do not have to be bit exact to achieve compatibility. Since individual designers implement algorithms in different manners, it is not possible to create a standard set of test vectors to assess conformance to a standar
24、d. This document describes a series of tests which are used to test conformance to specific aspects of the specification. These test do not necessarily ensure that the speech codecs operate satisfactorily under all possible input signals, and it is still a requirement of the manufacturer to ensure t
25、hat his implementation operates in a consistent manner. The purpose of these tests is to test for minimum performance levels and the manufacturer should attempt to provide the highest performance possible. The testing of the codecs described in this document is based upon quantitative tests with spe
26、cific pass/fail criteria. The major purpose of these tests is not to assess the performance between one manufacturers encoder and decoder, but to assess the Performance between any pairing of manufacturers encoders and decoders. This interoperability issue is of a critical nature to end users. The o
27、verall purpose of this standard is to provide a means for measuring performance levels while trying to ensure proper inter-operability with other manufacturers equipment. I STD-TIA TIA/EIA-L02=BABC-ENGL 1999 H b057943 0000b52 8bL TINEIA-102.BABC The issue of inter-operation can only be definitively
28、answered by testing all combinations of encoderldecoder pairings. With the number of equipment manufacturers expected to supply equipment this may well be a prohibitive task. This standard takes the approach of defining a reference speech codec and then each manufacturer tests his implementation rel
29、ative to the reference. Specific parameters identified by the developer of the speech codec are then compared against the reference. The speech codec is said to be in conformance once the objective performance requirements have been satisfied. This document requires use of proprietary test equipment
30、 which may be purchased from Digital Voice Systems Incorporated. An alternative method of testing using Mean Opinion Scores (MOS) is described in 4. 2 STD.TIA TIAIEIA-LW-BABC-ENGL my m b057w 000053 TB m TIAEIA-102.BABC 2 Overview The Project 25 Voice Codec Test Set (A25VCTS) is a complete system for
31、 testing and qualifying Project 25 voice codecs. The primary focus of this system is Type Approval Testing and Performance Verification Testing of prototype and production voice codecs. The A25VCTS also may be used for automated factory testing, voice codec development testing, and remote terminal c
32、ommissioning. The A25VCTS is divided into two primary components. The first component is the Test Computer which interfaces to the unit under test. The Test Computer and the Test Computer Software is used to perform and supervise Type Approval Testing and Performance Verification Testing. The second
33、 component, the I/O Interface Circuitry, is used to provide the circuitry necessary for connecting to the unit-under-test. The combination of these two components provides an automated system for evaluating the performance of a voice codec and comparing this performance against the appropriate objec
34、tive performance requirements. The remainder of this document is divided into three sections. Section 3 contains the Operation Manual for the Project 25 Voice Codec Test Set (A25VCTS). This section describes the operation of the Test Software and the procedure that must be followed to test a voice c
35、odec. Sections 4 and 5 contain descriptions of the Test Computer Hardware and Software, respectively. Section 6 lists the Objective Performance Requirements that are tested for each prototype voice codec. The Project 25 standard reference voice codec is the VC-20-PRJ25 voice codec module, which is a
36、vailable separately from DVSI. The VC-20-PRJ25 may be used in any of the tests described in this document to provide measurement data to compare to the unit-under-test. Such comparisons may be used for diagnostic purposes, but do not contribute to any of the pass/fail criteria of these tests. For a
37、complete description of the VC-20-PRJ25 reference voice codec, the VC-20-PRJ25 Manual should be consulted 3. 3 STD.TIA TIA/EIA-LOZ-BABC-ENGL 1999 m 6057743 0000b54 b34 e TIALEIA- 102.BABC DSP 4 Boards(2) 3 A25VCTS Operation Manual The Test Computer is powered up by turning on the power switch locate
38、d at the rear of the unit. After power up, the Test Computer performs memory checks and loads operating software from the hard disk. After completing the startup procedures, the Project 25 voice codec test software automatically begins execution and displays the following menu: YO Interface Channel
39、UF 4-V Circuitry MAIN MENU I - Run Loopback Test 2 - Run Type Approval Test O - Quit Enter Item Number (0-2) 3.1 Run Loopback Test In the Loopback Test, the test equipment should be configured as shown in Figure 3-1. The unit-under-test should be looped-back from its analog output to its analog inpu
40、t. During the Loopback Test the test computer transmits 7.2 kbps channel data to the unit under test. The voice codec under test decodes the received data and loops the data back to the encoder. The test computer records the data from the encoder. The encoder data is analyzed to estimate the followi
41、ng parameters: /I Speech I/F 4 STDmTIA TIA/EIA-LOZ*BABC-ENGL L797 m 6057743 0000b55 570 E TIALEIA- 1 02. B ABC Frequency Response - The combined decoder output and encoder input frequency response is computed by comparing the received encoder data with a stored reference. The computed frequency resp
42、onse is displayed as amplitude (dB) vs. frequency (O - 4000 Hz). For digital loopback, this curve should be flat at O dB. The upper bound for the frequency response is displayed as a magenta curve. The lower bound for the frequency response is displayed as a red curve. The measured frequency respons
43、e must be within these bounds to pass the frequency response test. Gain - computed as the ratio between the measured energy and the reference energy. Spectral Distortion - a measure of the dissimilarity between the measured spectrum and the reference spectrum expressed in dB. When the two spectra ar
44、e very similar, a large negative number results. When the two spectra are dissimilar, a number near O dB results. Period Mean Deviation - the average difference between the measured pitch period and the true pitch period in samples. Period Standard Deviation - the standard deviation of the measured
45、pitch period in samples. Maximum Deviation - the maximum error of the measured pitch period from the true value in samples squared. Pitch Errors - the percentage of frames that contain pitch errors large enough to alter the number of harmonics from the correct value. Unvoiced Errors - the percentage
46、 of unvoiced harmonics that are declared voiced. 5 Voiced Errors - the percentage of voiced harmonics that are declared unvoiced. DSP 4 Boards (2) - The requirements for these parameters are specified in Section 6.1 SpeechUF +- + I/O Interface Unit Under Test +- Circuitry + Channelm 3.2 I Run Type A
47、pproval Test 01 L 1 I I I I - Test Computer Figure 3-2: Configuration for Type Approval Tests When the Run Type Approval Tests option is selected, the test equipment should be configured as shown in Figure 3-2. The following menu is displayed: TYPE APPROVAL TESTS 1 - Run All Decoder Tests 2 - Run In
48、dividual Decoder Tests 3 - Run All Encoder Tests 4 - Run Individual Encoder Tests 5 - Continuous Testing Until Failure O - Quit Enter Item Number (0-4) 3.2.1 Run All Decoder Tests All of the decoder tests listed in Section 3.2.2 are executed sequentially. After all decoder tests are executed, a summ
49、ary of the results of the decoder tests is displayed. 3.2.2 Run Individual Decoder Tests Before running these tests, the test equipment should be configured as shown in Figure 3-2. The performance requirements for the parameters measured in the decoder tests are given in Section 6.2. When this option is selected, the following menu is displayed: DECODER TYPE APPROVAL TESTS 1 - Test i - Decoder Frequency Response 2 - Test 2 - Medium Pitch, High Amplitude 3 - Test 3 - Medium Pitch, Medium Amplitude 4 - Test 4 - Medium Pitch, Low Amplitude 5 - Test 5 - High Pitch 6 - Test 6 - L
