Ok, but the microphone converts the air vibrations into electric vibrations. People have picked up radio in their braces and fillings. It doesn't seem entirely unreasonable to guess that an electromagnetic radiation signal vibrating at the same rate as some of the electric signals in the cables and sampling device might cause audible interference in the result.

/st wrote: /> BJaY wrote: /> > Hi, /> > I'm looking to do some high sample rate stuff - 500kHz or more /> /> Where did you get a microphone and preamp that would respond at /> that frequency? You will be up into maritime radio communication //> band, approaching AM radio band. I wonder if you will have problems /> with interference. /> / /Common misconception... Very high frequency audio does not equal /electromagnetic radiation (radio, etc.). Audio is the compression and /expansion of air, so it isn't really affected by EMI. / /Are you using another ultrasonic transducer to receive the signal? Is /it necessary to capture the entire waveform, or just the envelope? If /you need an accurate waveform, your best bet would likely be to build /your own A/D circuit. Otherwise, rectify it, use an LP filter, and /you're good to go. /TimH I'll make sure everything is appropriately shielded. I'm more interested in generating sound than recording initially, but I'd like to pick it up, just to check the set up is working OK. I've seen devices that will repeat a waveform at a high frequency but I need a constantly changing signal so a D/A that runs at 500kHz or so, and can receive a continuous stream of samples is required. Shurely some of the high end audio guys have taken the 'higher sample rate sounds better' addage to the extreme ? Bruce.