Hi,
Recently we had a issue in FM sensitivity i.e. Tuner not able to pick-up signal and produce audio at low signal strength condition. Especially at the Frequency 90.8 MHz FM Station.
Based on our analysis, we found that 2.1 MHz Switching frequency from the audio amplifier (TPA6404) is getting coupled to the FM RF input line of the tuner and overall noise floor got increased. Due to this, we are hearing noise at the speaker output at even moderate FM Signal Strength of 25 -30 dBuV (generated from FM Signal Generator).
Could you please advise us to filter out noise at the FM RF Input path?
