0
\$\begingroup\$

I have connected a TEA5767 to my Arduino board using I2C and can tune it fine (see instructable.com). As antenna a ~70cm long simple cable is connected. I've connected a cheap 5V amplifier. Unfortunately, the sound quality is bad - very much static noise (though the sender is only 2km air distance away) - with forced mono it is acceptable but still not good. When scanning for stations (muted) there also is noise. Disconnecting the inputs of the amplifier causes absolutely no noise.

Update according to the comments: When using the FM application on my Motorola/Android phone and put it near the Arduino, it does not cause noise, so the Arduino seems not to "send" - but maybe it is caused by the connected VCC? I've put a 100nF and a 100uF capacitor near the FM receiver and amplifier - it makes absolutely no difference. For me it looks like the TEA5767 causes the noise.

Does someone has an idea how to improve the sound quality?

\$\endgroup\$
  • 1
    \$\begingroup\$ It is possible that you Arduino board is generating interference. Microcontroller oscillators generate harmonics up into VHF. Try placing an FM radio next to your tuner and see if there is interference. \$\endgroup\$ – user1582568 Jan 7 '16 at 18:03
  • \$\begingroup\$ What are you using for an audio amplifier. Also, can you describe better your "sound quality is bad". Is audio buzzing, distorted, tinny, mushy, what ? Tune off channel, and perhaps describe if it sounds like normal FM off channel. \$\endgroup\$ – Marla Jan 7 '16 at 19:03
  • \$\begingroup\$ Add any additional information to the question (as in edit question), not to comments. \$\endgroup\$ – Marla Jan 7 '16 at 19:08
  • \$\begingroup\$ A picture of your wiring could help \$\endgroup\$ – Passerby Jan 12 '16 at 18:48
1
\$\begingroup\$

Your mention of the audio still having noise when you are "scanning station (muted)", leads me to believe the problem could be your "cheap" audio amplifier.

However, it is difficult to reconcile why you get acceptable audio when forced mono.

Try putting a de-coupling capacitor (perhaps 0.1 uf) across the +5 volts of your audio amplifier (+5v to board ground). Put the capacitor right on the amplifier board if you can.

\$\endgroup\$
  • \$\begingroup\$ Does not make any difference - see the updates question. \$\endgroup\$ – Thomas S. Jan 13 '16 at 8:31
0
\$\begingroup\$

Your noise is coming from the I2C bus, most likely when 'reading' the status in your main loop, or updating an LCD over the I2C. I am troubleshooting the same problem right now, it may be the VCC needs more bypass on the FM receiver module or the pullups on the I2C lines need a different value or some combination of both.

\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.