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pothosware / SoapyRTLSDR

SoapySDR RTL-SDR Support Module
https://github.com/pothosware/SoapyRTLSDR/wiki
MIT License
134 stars 31 forks source link

Make getFrequencyRange aware of directSamplingMode #64

Open ryansuchocki opened 1 year ago

ryansuchocki commented 1 year ago

I've extended the implementation of getFrequencyRange() to be aware of direct sampling mode.

This uses librtlsdr's rtlsdr_get_xtal_freq(). The librtlsdr header indicates that, in direct sampling mode, the tune-able range is from zero to the xtal frequency.

This seems to be necessary in order to get GQRX to let me tune below 28MHz when using SoapyRTLSDR over SoapyRemote.

zuckschwerdt commented 1 year ago

Thanks. LGTM! Haven't thought about it before, but I guess we should not expect a fixed return from getFrequencyRange(). For reference, BladeRF does something like this too: https://github.com/pothosware/SoapyBladeRF/blob/85f6dc554ed4c618304d99395b19c4e1523675b0/bladeRF_Settings.cpp#L532-L545