Note

Setting the

Interleaved

Transfer Mode

For example, if a configuration consists of two digitizers and both channels on each digitizer are used, the maximum sample rate for each digitizer is:

40 MSamples / 4 channels = 10 MHz

As another example, if a configuration consists of two digitizers and only three channels are used, the maximum sample rate for each digitizer is:

40 MSamples / 3 channels = 13.3 MHz

For the digitizer using two channels this would be 26.6 MSamples/ second since a single sample trigger causes both channels to sample. For the digitizer using only a single channel, the sample rate would be

13.3MSamples/second. Together, the two digitizers are within the 40 MSample (80 MByte)/second Local bus transfer specification.

The maximum sample rates computed may not always be available using the digitizer’s internal reference. In those instances, select a slower sample rate that is available from the internal reference, or use an external reference or an external trigger source.

In addition to resetting the digitizer’s Local bus chip, setting the Local bus mode, and setting the data source, the interleaved transfer mode must be set. This is done using the commands:

VINStrument:CONFigure:LBUS:SEND:POINts <count >

VINStrument:CONFigure:LBUS:POINts:AUTO <mode >

<count > is the number of readings per block. If readings are taken on only one channel, <count > is set to 1. If readings are taken on both channels, <count > is set to 2.

Setting <mode > to OFF sets the interleaved transfer mode. In this mode the end-of-block flag is sent after each reading or set of readings. The end-of-frame flag is sent with the GENerator’s end-of-block flag.

406 Local Bus Interleaved Transfers

Appendix D

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Image 406
HP E1429A manual Setting Interleaved Transfer Mode, Local Bus Interleaved Transfers Appendix D