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Tried LNA gain adjustments but it does not help for the DIY antenna.

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Joris van Rantwijk 2014-05-29 21:32:32 +02:00
parent 844d0c1684
commit 6a5ccbb818
2 changed files with 5 additions and 3 deletions
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6
NOTES.txt
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@ -200,7 +200,11 @@ Radio4 reception improves from very bad to almost good.
However, strong stations (radio3) sound slightly worse with the DIY antenna However, strong stations (radio3) sound slightly worse with the DIY antenna
than with the basic DVB antenna. than with the basic DVB antenna.
May be caused by clipping due to too strong signal from antenna. Theory: Distortion caused by clipping I/Q samples due to strong antenna signal.
No, that's not it. Reducing LNA gain or IF gain does not help much;
small DVB antenna still sounds better than DIY antenna.
Difference only clear in stereo mode.
Don't know what's going on here, maybe the DIY antenna is just not good.
Local radio stations Local radio stations

2
TODO.txt
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@ -1,5 +1,3 @@
* (quality) solve issues with bad sound due to strong antenna signal
(experiment with adaptive LNA gain or adaptive IF gain)
* (speedup) maybe replace high-order FIR downsampling filter with 2nd order butterworth followed by lower order FIR filter * (speedup) maybe replace high-order FIR downsampling filter with 2nd order butterworth followed by lower order FIR filter
* (feature) implement RDS decoding * (feature) implement RDS decoding
* (quality) consider FM demodulation with PLL instead of phase discriminator * (quality) consider FM demodulation with PLL instead of phase discriminator