Tomorrow I will take more pics with better focus display and the scope settings too so you can see better, thanks Mark.
Last edited:
To measure frequency with that type of scope, the knob in the lower right corner labeled "Var" has to be fully counterclockwise to the position that is labeled "Cal"
Then the time "Timebase" switch will be in the calibrated condition and we can use it to calculate the frequency of the displayed waveform.
(However, if the "Var" knob is got loose and slipped out of position, it should just be fully counterclockwise.)
Then the time "Timebase" switch will be in the calibrated condition and we can use it to calculate the frequency of the displayed waveform.
(However, if the "Var" knob is got loose and slipped out of position, it should just be fully counterclockwise.)
For example, if "Var" is fully counterclockwise in post #2,368 then we can see one cycle takes up 7 horizontal divisions. So it would would have a period of 7 x 10us. (7 x (10 x 10^-6))
Okay. 1 cycle takes approximately 2.4 divisions. So we need to calculate 1/( 2.4 x 10 us) which gives a frequency of approximately 41.666kHz. Of course the scope sweep rate calibration may not have been checked recently so it could be a little (or a lot) inaccurate. However, since your DVM is supposed to be good up to 200kHz, it might be reasonable to try measuring with it to compare with the scope measurement.
Okay. Looks like it the 44.1kHz LRCK frame clock for CD audio. That's probably what the USB board defaults to. Are you sure you are counting the pins as Amanero does? If you count from the wrong end you might end up on the wrong pin or something. The way I check is too look for three pins all next to each other that have DATA, BCLK, and LRCK (or FSCLK).
In Amanero pinout format, the pin in the pic above labeled "FSCLK" is the same as LRCK, its the frame sample rate clock. It should be the one at 44.1kHz
In Amanero pinout format, the pin in the pic above labeled "FSCLK" is the same as LRCK, its the frame sample rate clock. It should be the one at 44.1kHz
