Phase response of anti-aliasing filter

I am doing some measurements which require precise timing comparisons between signals acquired with both analog and digital channels. I’ve read somewhere that the analog channels have an anti aliasing filter with a cutoff at about 1/10 of the sample rate. Can I find the phase response of this filter somewhere? I want to know if the phase shifts enough such that I have to account for it in the timing measurements

You can look at the same channel as both digital and analog at the same time (two traces) so you can see exactly how your individual device is performing. Doing so will likely reduce the maximum sampling rate you can use so you may want to capture test data using just the digital channel of interest as both digital and analog, then capture your data of interest using different digital and analog channels.

When we calibrate our devices, we actually correct for variations in phase response. The group delay is effectively constant, and we also calibrate out the delay between the analog and the digital channels.

However, there is some small offset (+/- 1 sample, of the slower sample rate, digital or analog) however if you experimentally measure it, it will remain constant for the specific sample rates used.

What level of accuracy are you looking for?

Also, if you send me your device ID, I can lookup the frequency response characteristics in the calibration database. Not sure if it will be useful though.

You can find your device ID on the device info dialog.

Thanks all. I got all the info I needed.

As for accuracy, I’m looking for about 0.3 microseconds, which the Saleae is more than capable of providing with the sample rates above 3 MHz.