Logic 1.2.18 - what is the actual sampling rate for 1.563M?

1

In Logic 1.2.18, I have this setup:

saleae_1563
saleae_15631025×522 56 KB

As visible on the screenshot, it says Speed (Sample Rate): 1.563 MS/s.

However, if from Python API, I do: saleae_obj.get_all_sample_rates(), I get:

[(0, 50000000), (0, 12500000), (0, 6250000), (0, 3125000), (0, 1562500), (0, 781250), (0, 125000), (0, 5000), (0, 1000), (0, 100), (0, 10)]

… that is, 1563000 S/s rate is not listed, however 1562500 S/s is!

I export raw binary data from Saleae Logic, and then import in other programs, so I have to specify the sampling rate upon import. And obviously, if the actual sampling rate is 1.5625 MS/s, and I enter 1.563 MS/s, I’m off by some 500 S/s, which I’d rather not be.

So, what is the actual sample rate in this case, 1.563 MS/s or 1.5625 MS/s?

2

Good catch, I never noticed the UI rounding before, and that number’s been in there for years.

It’s 1.5625. All analog sample rates on the pro devices are a power of 2 division of 50 MSPS. This sample rate is 50MSPS / 32.

The 2.x alpha software displays the rate correctly.

1 Like
3

Many thanks for confirming, @markgarrison :

It’s 1.5625

Great to have this confirmed, as otherwise there was no other documentation I could find on this.

Also, good to know that:

All analog sample rates on the pro devices are a power of 2 division of 50 MSPS. This sample rate is 50MSPS / 32.

Thanks again!