Software differential signal generator (or MP3 player for that matter)

Question

I chose ADAU1761, but the topic is not only related to ADAU1761. I would be grateful if the administration moves the topic to a right place. 
 Colleagues, I have an idea to have a pocket differential signal generator. 
 The simplest thing is to use an MP3 player with a file where one channel has a positive half-wave, and the other channel has a negative half-wave. 
 I have not found a tool for generating such a specific signal. There are many tools where you can flip the signal of one channel by 180 degrees, but you need a half-wave, not just an inverted phase. Please suggest the right software. 
 Perhaps you can suggest a solution (without an MP3 player) for feeding a differential signal in cases where it is not possible to constantly speak into an XLR microphone or connect another device as a generator.

DaveThib · Answer

Hello OctopusDev 
 This is fairly easy to do. Yes, you can use the 1761 but the good old ADAU1701 is also a great part to use for such a thing. 
 You can use the hard clippers to do this. Set one to clip the top and the other to clip the bottom of the same sine wave output. 
 
 Here is what the project would look like

When you run the graphs you will see the results. 
 
 I stopped these at different times so they do not exactly line up but you will get the idea. 
 The clippers are located in the non-linear processors section of the toolbox. 
 
 Keep in mind that when you run this out to a DAC it will not take kindly to the sudden stopping of the waveform so there will be some ringing that will happen due to the filters in the DAC. The best DACs for this would be an R2R type which are getting difficult to find. 
 I suppose someone in the data converters group here at ADI may be able to help you with that. A clipped waveform like that has a lot of high harmonics that will be truncated causing the ringing and some aliasing. 
 Dave T

Partner Forums

Partner Libraries

Products Mentioned

Associated Drivers

Software differential signal generator (or MP3 player for that matter)