3 ms·

Off topic: I am looking for SDR project ideas for a signal processing class (something to do during lockdown I suppose). Right now I'm thinking of doing a prett

by pizza 7y ago

Off topic: I am looking for SDR project ideas for a signal processing class (something to do during lockdown I suppose). Right now I'm thinking of doing a pretty rudimentary auto-radio-remix project (ie sample multiple radio stations simultaneously, trigger samples to form a song) or some augmented reality plane flight vector visualization project (ie movement tracking using some kind of sensor fusion between smartphone gps + smartphone camera + radio ads-b data). Any more ideas appreciated!

jcims 7y ago
The second project is already part of flight radar 24. One I tried to do a while back but didn’t have enough DSP chops for was a SSB tuning correction plug-in. If you mistune SSB (LSB/USB), the voices will be off and have a robotic chipmunk sound to them. You can find the correct tuning by looking at the frequency relationship of the fundamental and first two or three harmonics in the voice. But it’s pretty tricky because teaching that while someone is talking is a handful. Limited interested audience for that one though. A mobile TEMPEST attack app would make some waves. A mobile DECT scanner would also be interesting but a bunch of work.
jhallenworld 7y ago
Do the inverse of the posted project: transmit an entire band, for example all ~110 channels of the AM broadcast band. Use an old AM radio to tune to around, and hey every station is playing songs you like :-) It would be nice if this was a UNIX command with paths to ~110 folders of MP3s or something like that. What is the limit for something like this? I mean with a given DAC of N bits, what resolution do you get with M channels without overflowing?
- drmpeg 7y ago
  I've done ten channels of broadcast FM with GNU Radio. The limiting factor is processing power. Here's a spectrum with all channels sending the same audio. http://www.w6rz.net/fm10.png http://www.w6rz.net/fm10.png
deleted 7y ago
[deleted]

by pizza 7y ago

jcims 7y ago

The second project is already part of flight radar 24. One I tried to do a while back but didn’t have enough DSP chops for was a SSB tuning correction plug-in. If you mistune SSB (LSB/USB), the voices will be off and have a robotic chipmunk sound to them. You can find the correct tuning by looking at the frequency relationship of the fundamental and first two or three harmonics in the voice. But it’s pretty tricky because teaching that while someone is talking is a handful. Limited interested audience for that one though. A mobile TEMPEST attack app would make some waves. A mobile DECT scanner would also be interesting but a bunch of work.

jhallenworld 7y ago

Do the inverse of the posted project: transmit an entire band, for example all ~110 channels of the AM broadcast band. Use an old AM radio to tune to around, and hey every station is playing songs you like :-) It would be nice if this was a UNIX command with paths to ~110 folders of MP3s or something like that. What is the limit for something like this? I mean with a given DAC of N bits, what resolution do you get with M channels without overflowing?

drmpeg 7y ago
I've done ten channels of broadcast FM with GNU Radio. The limiting factor is processing power. Here's a spectrum with all channels sending the same audio. http://www.w6rz.net/fm10.png http://www.w6rz.net/fm10.png

deleted 7y ago

[deleted]