search

f4exb / sdrangel

SDR Rx/Tx software for Airspy, Airspy HF+, BladeRF, HackRF, LimeSDR, PlutoSDR, RTL-SDR, SDRplay and FunCube
GNU General Public License v3.0
2.91k stars 441 forks source link

DATV Decoder Delta F #637

Closed m0dts closed 4 years ago

m0dts commented 4 years ago

Small bug regarding 'Delta F' for DATV Demdulator.

If i use the mouse to select the area of spectrum for the decoder the 'Delta F' is updated in the DATV demodulator window but the demodulator does not respond and i don't decode the signal. If i then adjust the 'Delta F' tuning with the mouse on the DATV demodulator window the demodulator responds and starts to decode the signal.

Missing action when the spectrum is clicked to adjust decoder? I can provide a video if required.

Thanks Rob

f4exb commented 4 years ago

You cannot "select an area" of the spectrum all you can do is point and click and the center frequency of the demodulator is moved to that point.

This is only in the case there is only one demodulator. If you have more than one in the passband (channels window) then this functionality is disabled. This is because there is no indication of which channel to move.

This is only a facility for single channel setups. You may always drag the center line of any channel to obtain the same result.

m0dts commented 4 years ago

Ok thanks, sorry i did not mean select area but just click.

I understand the problem if multiple demodulators, not easy to implement. In single channel mode this should work?

Rob

f4exb commented 4 years ago

Yes and I just verified this for DATV plugin.

m0dts commented 4 years ago

Thanks, Here it does not work as expected... The frequency is updated on the demodulator panel display when i click the spectrum but the decoder does not see the change. If i then adjust the frequency by just 1Hz on the demodulator panel it then responds and locks onto the signal. I'm using win x64 4.16.1.

f4exb commented 4 years ago

Which signal is it? DVB-S or DVB-S2? and with which characteristics S/R, modulation, FEC?

m0dts commented 4 years ago

It happens on all modes/sr/fec. The constellation is just noise until i change the channel frequency manually by just a small amount, then i see the constellation appear.

m0dts commented 4 years ago

I've made a short video here to explain: https://www.dropbox.com/s/rz7t5k1cie6mxci/2020-09-18%2018-27-00.mp4?dl=0

f4exb commented 4 years ago

I found that the point and click does not actually change the plugin shift frequency. This is probably the issue. Of course tweaking the thumb wheels will fix this because then the face frequency gets correctly set.

In the same situation the NFM demod works correctly so by comparing the code the issue could be revealed.

Easy fix: it uses an old scheme that was changed in favor of having the shift frequency in the settings. However this was never changed in the method (slot) that handles the point and click.

f4exb commented 4 years ago

Fixed in v4.17.0