search

bastibl / gr-keyfob

Transceiver for Hella wireless car key fobs.
172 stars 31 forks source link

Samplerate and Resamplerate #4

Closed herrfeder closed 7 years ago

herrfeder commented 7 years ago

Hello Bastian,

i don't have any Hella manufactured keys around here. So I'm trying to adapt your code for other key fobs. Therefore I have two questions on your keyfob_decode_wav example. Have you done any preprocessing to your input file or does it simply match with 48kHz Samplerate? How did you calculate your Resamplerate(3400*5)?

Thank you in advance.

bastibl commented 7 years ago

The input file was recorded with a sample rate of 48kHz using gqrx. The resample rate was chosen to have an integer number of samples per symbol. The symbol rate was determined manually with a tool like inspectrum.

herrfeder commented 7 years ago

Okay, thank you, I'm not able to record a proper signal on 433MHz without downmixing with gqrx on samplerate of 48kHz. Inspectrum is great, I used baudline, but inspectrum is much better for this purpose.