9 Trau Testing with 8 Bit A- and µ-law PCM Test Sequences

06.073GPPHalf Rate Speech: Test Sequence for GSM Half Rate Speech CodecTS

In the previous clauses tests for the transcoder in the TRAU are described using 13 bit linear test sequences. However, these 13 bit test sequences require a special interface in the Trau and do not allow testing in the field. In most cases the TRAU has to be set in special mode before testing.

As an option, the speech codec tests can be performed with A/ law compressed 8 bit PCM test sequences on the A interface. These modified input test sequences (*-X.INP) are generated from the original sequences by A or  law compression. As an input to the encoder they result in modified encoder output sequences (*-X.COD). The same *.dec decoder input sequences as in clause 6.2.2. are then used to produce the output sequences *-X.OUT, which are A- or µ-law compressed.

The A- and µ-law compression and decompression does not change the homing frames at the encoder input. The format of all A- and -law PCM files *-X.INP and *-X.OUT is one sample (8 bit) per byte. The format of all other files is as described in clause 5.

All files are provided in archive en_300968v080001p0.ZIP which accompanies the present document. The ‘X’ in the tables below with the filenames stands for A (A-law) and U (-law), respectively. The decoder input files *.dec are the same as in Table 5 and are not described in this clause.

Table 8: Location and size of compressed 8 bit PCM speech codec test sequences

Disk No.

File Name

No. of frames

Size (bytes)

6/7

6/7

6/7

SEQ01-X.INP

SEQ01-X.COD

SEQ01-X.OUT

2 359

377 440

94 360

377 440

6/7

6/7

6/7

SEQ02-X.INP

SEQ02-X.COD

SEQ02-X.OUT

781

124 960

31 240

124 960

6/7

6/7

6/7

SEQ03-X.INP

SEQ03-X.COD

SEQ03-X.OUT

413

66 080

16 520

66 080

6/7

SEQ04-X.OUT

76

12 160

6/7

SEQ05-X.INP

1

160

Table 9: Location and size of compressed 8 bit PCM DTX test sequences

size

(bytes)

Disk No.

File Name

No. of Frames

*.INP

*.COD

*.OUT

8/9

DTX01-X

460

73 600

18 400

73 600

8/9

DTX02-X

886

141 760

35 440

141 760

8/9

DTX03-X

125

20 000

5 000

20 000

8/9

DTX04-X

317

50 720

12 680

50 720

8/9

DTX05-X

37

5 920

1 480

5 920

8/9

DTX06-X

240

38 400

9 600

38 400

8/9

DTX07-X

1 188

190 080

47 520

190 080

In addition to the testsequences above, special input (seqsyncX.inp) and output (syncxxxX.cod) sequences for frame synchronization are provided. The X again stands for A and  law compressed PCM. The synchronization procedure is described in clause 8.

Table 10: Location, size and justification of compressed8 bit PCM test sequences

Disk No.

Purpose of Sequence

Name of Sequence

No. of Frames

Size in Bytes

Justification

10/11

Frame Synchronization (input)

SEQSYNCX.INP

4

640

10/11

Frame Synchronization (output)

SYNC000X.COD

SYNC001X.COD

SYNC002X.COD

"

"

"

SYNC159X.COD

1

1

1

"

"

"

1

40

40

40

"

"

"

40

Right

Right

Right

"

"

"

Right