5 Test sequence format

3GPP46.054Release 17Test sequences for the GSM Enhanced Full Rate (EFR) speech codecTS

This clause provides information on the format of the digital test sequences for the GSM enhanced full rate speech transcoder (GSM 06.60 [2]), Voice Activity Detection (GSM 06.82 [6]), comfort noise (GSM 06.62 [4]) and the discontinuous transmission (GSM 06.81 [5]).

5.1 File format

The test sequence files are provided in archive ts_100725v080100p0.zip which accompanies the present document.

Following decompression, four types of file are provided:

– Files for input to the GSM enhanced full rate speech encoder: *.INP

– Files for comparison with the encoder output: *.COD

– Files for input to the GSM enhanced full rate speech decoder: *.DEC

– Files for comparison with the decoder output: *.OUT

The *.DEC files are generated from the corresponding *.COD files.

Tables 1, 2, 3 and 4 define the formats of the four types of file.

Each speech parameter within the speech frame of 244 bits/20 ms is contained in a serial string of 16 bit words, where each word contains the value of one bit of the parameter. In each string of n 16 bit words containing the n bits of a parameter, the most significant bit of the parameter is written first, and the least significant bit is written last. The bit value contained in a single 16 bit word is either 0x0000 or 0x0001 (right justified) for the binary values of “0” and “1”, respectively. See table 6 of GSM 06.60 [2] for the order of occurrence and bit allocation of speech parameters within the speech frame of 244 bits/20 ms.

The samples in the encoder input signal and in the decoder output signal are left justified.

5.2 Codec homing

Each *.INP file includes two homing frames at the start of the test sequence. The function of these frames is to reset the speech encoder state variables to their initial value. In the case of a correct installation of the ANSI-C simulation (GSM 06.53 [7]), all speech encoder output frames shall be identical to the corresponding frame in the *.COD file. In the case of a correct hardware implementation undergoing testing, the first speech encoder output frame is undefined and need not be identical to the first frame in the *.COD file, but all remaining speech encoder output frames shall be identical to the corresponding frames in the *.COD file.

Each *.DEC file includes two homing frames at the start of the test sequence. The function of these frames is to reset the speech decoder state variables to their initial value. In the case of a correct installation of the ANSI-C simulation (GSM 06.53 [7]), all speech decoder output frames shall be identical to the corresponding frame in the *.OUT file. In the case of a correct hardware implementation undergoing testing, the first speech decoder output frame is undefined and need not be identical to first frame in the *.OUT file, but all remaining speech decoder output frames shall be identical to the corresponding frames in the *.OUT file.

Table 1: Encoder input sequence (*.INP) format

Name	Description	No. of bits	Justification
s(n)	Encoder input signal	13	Left

Table 2: Encoder output sequence (*.COD) format

Name	Description	No. of bits	Justification
Speech parameters
SPEECH	Serial stream of speech parameter bits to the channel encoder	244	Right
Additional information
VAD SP	Voice activity detection flag SP flag	1 1	Right Right

Table 3: Decoder input sequence (*.DEC) format

Name	Description	No. of bits	Justification
Additional information
BFI	Bad Frame Indicator flag	1	Right
Speech parameters
SPEECH	Serial stream of speech parameter bits to the channel encoder	244	Right
Additional information
SID TAF	Silence Descriptor flag Time Alignment Flag	1 1	Right Right

Table 4: Decoder output sequence (*.OUT) format

Name	Description	No. of bits	Justification
s'(n)	Decoder output signal	13	Left