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nulinspiratie / SilQ

Software for quantum control of donor atoms in silicon
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Triggering/Acquisition bug in Keysight PXIe system #297

Open maij opened 2 years ago

maij commented 2 years ago

We have encountered reproducible issues where it appears that triggers are being ignored 50% of the time when running certain pulse sequences. It seems to strongly depend on the exact duration of a pulse sequence.

One temporary workaround is to set a minimum pulse duration in the ESR/NMR parameters. I have not been able to identify the source of the bug as yet.

maij commented 2 years ago

This bug may actually be because the Keysight AWG sample rate was set to its maximum rate (500 MSPS) which causes the channels to de-synchronize. This does not seem to happen when the sample rate is 100 MSPS or less.

maij commented 2 years ago

Adding general buggyness regarding this interface, the AWG queuing system is written to calculate things based on a 100 MHz clock cycle, but this can cause large rounding errors when the actual sample rate is larger. This is especially problematic for pulses with few points but many cycles, because the rounding errors are essentially multiplied by the number of repeated cycles.

This interface could really use a full overhaul in how it manages the waveform queuing, and updating it to handle the M3202A cards.