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Old 07-03-2018, 7:35 AM
boatbod boatbod is online now
Join Date: Mar 2007
Location: Talbot Co, MD
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Originally Posted by NebraskaCoder View Post
What is the best way to find my tuning values like sampling rate, ppm, offset, etc...? It is harder for me to see the ppt graph in detail. It seems multiple different sets of values work. I have an RTL2832U dongle.

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Sample rate can start at 960000 as that value world on any rtl dongle. In practice you may need to lower it later to reduce audio stutter on the rpi3.

ppm (-q) is usually best derived iteratively. Use the fft plot and/or mixer plot to center the control channel signal peak by adjusting ppm up or down. On tcxo dongles you usually only need a ppm value of +/-1 our so.

finetune (-d) is set after ppm to center the mixer peak. If you need fine tune greater than about +/-400 you should consider adjusting ppm again.

ftt plot shows the big picture. When you can no longer see fine enough detail, switch to the mixer plot and aim to get the 'balance' value as close to 0 as possible.
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