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F5OEO / rpitx

RF transmitter for Raspberry Pi
GNU General Public License v3.0
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make chirp sweep in one direction #235

Open giordyb opened 3 years ago

giordyb commented 3 years ago

Hi I'd like to use rpitx as a frequency sweeper in order to test some filters with an oscilloscope. Is there a way to modify chirp so that it sweeps in one direction only? I tried to look at the code but I cannot figure out what is being passed to the SetFrequencySample() function, c is not my first language...

F5OEO commented 3 years ago

See https://github.com/F5OEO/rpitx/blob/7339faad4b2178a92a912c0a1cc09da8b28e7af1/src/chirp/chirp.cpp#L94

giordyb commented 3 years ago

Thank you!

I was able to do something close to what I was looking for by modifying the tune.cpp and doing a loop calling the SetFrequency function.

Would you mind explaining the difference between the approach of the tune.cpp and chirp.cpp? It looks like they both take a frequency but it seems that chirp is a lot faster switching frequency.