User manual

ASI-310 User Manual (Iss. 03) Configuration • 4–3

ASI-to-310 Converter Settings

The ASI to 310 tab provides options for configuring the ASI-to-310 converter feature.

To set up the ASI-to-310 converter:

1. Select the ASI to 310 tab.

ASI to 310 Tab

2. Use the 310 Output Bit Rate options to set the output data rate.

3. Use the Output Packet Size options to specify the number of bytes per packet in the

310 output.

This is normally 188 bytes, but you can set it to 204 or 208 bytes if needed for your

application. If the input packet size is different from the output size you specify, the

converter adjusts the number of dummy error-correction bytes appended to the basic

188-byte payload to achieve the desired total packet length.

4. Configure the PCR Restamping option.

It should normally be left at the On setting, since this minimizes PCR error and jitter in

the output. It does this by adjusting the PCR values to account for the slightly variable

packet processing delays caused by adding or deleting null packets to maintain the

specified output data rate and/or modify the packet size.

5. Set the 310 Output Clock to either Free-running or Lock to 310 Input.

If you have a high-accuracy high-stability 310 signal available, you can connect it to the

310 Input jack, and set this variable to Lock to 310 Input. Otherwise, it should be set to

Free-running which uses an accurate on-board frequency reference to generate the

output data rate.

6. Use the 310 Input Bit Rate to set the 310 reference input data rate. This must be set to

the correct value if you have selected Lock to 310 Input as the 310 Output Clock setting,

or if you are using the 310-to-ASI converter as discussed in the next section.

Note — When the 310-to-ASI converter is active and its input is from the ASI-to-310

converter, it is essential that you set the 310 Output Clock to Free-running. If you set it

to Lock to 310 Input, the converter would effectively lock its 310 clock to itself, which

would produce unspecified and possibly non-compliant output signals.