6.	Proposed amendments to Recommendation 0.133

EQUIPMENT FOR MEASURING THE PERFORMANCE OF PCM ENCODERS AND DECODERS

Delete Note 1 in § 1.1. and renumber the footnotes.

Amend § 3.1.2.1 as follows:

"3.1.2.1	Level conditions and frame format

The instrumentation is required to operate satisfactorily with interface levels in accordance with Recommendation G.703 (7).

One or both of the following conditions of interface and frame formats, including extended frame formats and Cyclic Redundancy Check (CRC) procedures, shall be provided:

-	at 1 544 kbit/s Recommendation G.703 (7), § 2,

Recommendation G.733 (3) and Recommendation G.704 (11);

-	at 2 048 kbit/s Recommendation G.703 (7), § 6,

Recommendation G.732 (2) and Recommendation G.704 (11)."

In Table 1/0.33, the second entry should read: "Variation of gain (loss) with time" in place of the word "Stability". A footnote should also be added to Table 1 stating that this parameter is called "Stability" in Recommendations G.712, G.714 and G.792.

In Table 1/0.133 delete the references to envelope delay and envelope delay distortion and the associated table entries.

Add to Table 1/0.133:

"Frequency of a repetitive signal ----0".

Delete Note a) to Table 1/0.133 and renumber the notes.

Add the following new paragraphs to the Recommendation:

"3.3.8	Frequency of a repetitive signal

As an option it shall be possible to measure and display the frequency of any repetitive signal in the frequency range 200 and 4 000 Hz applied to the input of the instrument at any level in the range defined in § 3.3.2. The result shall be displayed to a resolution of 1 Hz. The measurement shall be made to an accuracy of at least 50.10-6.

3.4.4.2	As an option an interface shall be provided to enable an externally generated digital signal to be applied to any selected speech time slot. The interface shall meet the requirements of a co-directional interface as defined in Recommendation G.703."

Add new paragraphs as below:

"3.4.5.1.5 The instrument shall be capable of generating frame formats including CRC multiframes and CRC check bits, in accordance with Recommendation G.704 § 2.3.

3.4.5.1.6 Where a CRC multiframe is being generated it shall be possible to modify any bit of the CRC multiframe alignment signal."

Add:

"3.4.5.1.7 As as option an interface shall be provided to allow the signalling bits associated with any selected speech time slot to be controlled from an external source when channel associated signalling is in use."

Add new § 3.4.5.2.1 as below:

"3.4.5.2.1 The instrument shall be capable of generating frame formats including CRC multiframes, in accordance with Recommendation G.704, § 3.1."

Renumber existing §§ 3.4.5.2.1 and 3.4.5.2.2 to 3.4.5.2.2 and 3.4.5.2.3 respectively.

Renumber existing § 3.4.5.2.3 to § 3.4.5.2.4 and amend as follows:

"3.4.5.2.4 Where the 12 frame multiframe is being generated it shall be possible to modify the eighth bit of each channel time slot in frame 6 and 12 when channel associated signalling is in use. All signalling channels may be provided with the same pattern."

Add new § 3.4.5.2.5 as below:

"3.4.5.2.5 Where the 24 frame multiframe is being generated it shall be possible to modify the eighth bit of each channel time slot in frame 6, 12, 18 and 24 when channel associated signalling is in use. All signalling channels may be provided with the same pattern."

Add:

"3.4.5.2.6 As an option an interface shall be provided to allow the signalling bits associated with any selected speech time slot to be controlled from an external source when channel associated signalling is in use."

Amend 3.5.6 as follows:

"3.5.6	Signalling bits

3.5.6.1 As an option the signalling bits associated with any speech time slot shall be selectable for display when channel associated signalling is in use.

3.5.6.2 As an option, an interface shall be provided to enable the signalling bits associated with any selectable speech time slot to be monitored by an externally connected instrument when channel associated signalling is in use."

Amend § 3.5.7.1 as below:

"3.5.7.1 PCM multiplex to Recommendation G.732 (2): loss of signal, loss of frame alignment, loss of multiframe alignment where channel associated signalling is in use, loss of CRC multiframe alignment, state of bit 1 of time slot 0 of frame containing frame alignment signal, state of bits 1 and 3 to 8 of time slot 0 of frame not containing frame alignment signal, state of bit 6 of time slot 16 of frame 0, and display of information conveyed via the CRC procedure as defined in Recommendation G.704."

Amend § 3.5.7.2 as below:

"3.5.7.2 PCM multiplex to Recommendation G.733 (3)

3.5.7.2.1 Loss of signal, loss of frame alignment, loss of multiframe alignment when channel associated signalling is in use.

3.5.7.2.2 When a 12-frame multiframe is being monitored the state of bit 8 of each channel in the sixth and twelfth frames and the state of bit 1 of the twelfth frame.

3.5.7.2.3 When a 24-frame multiframe is being monitored the state of bit 8 of each channel in the sixth, twelfth, eighteenth and twenty-fourth frames, the state of bit 1 of the twelfth frame, and the display of information conveyed via the CRC procedure as defined in Recommendation G.704."

Add:

"3.5.8	Frequency of a repetitive signal

As an option it shall be possible to measure and display the frequency of any repetitive signal in the frequency range 200 Hz to 4 000 Hz applied at a level in the range defined in § 3.5.1. The result shall be displayed to a resolution of 1 Hz. The measurement shall be made to an accuracy of at least 50.10-6."

Add:

"3.5.9	External speech timeslot interface

As an option an interface shall be provided to enable the digital signal contained in a selected speech time slot to be extracted and applied to a separate instrument. The interface shall meet the requirements of a co-directional interface as defined in Recommendation G.703."