Delta modulation experiment

When I first learned about Delta modulation I realized it has a lot of potential for low-digital-bandwidth voice communication. With a single bit data-frame audio communication will be quite easy. This is one among my old experiments. I simulated a delta-modulation-demodulation system with various quantization steps and figured out it’s frequency response.

I did set the sampling rate to 4 times (as suggested by a communication book) the Nyquist Rate. That is 2 x 20kHz x 4.

The surface plot is the correlation co-efficient at those particular quantization steps and input sinusoidal frequency.

Here is the response,

I found out that it’s quite good for voice communication, upto 8kHz it will perform pretty well. The red region suggests good communication will occur upto 8kHz at small quantization steps. The the quality of the communication will gradually fall.

Next I will put a audio file through delta modulation.

The MATLAB code with the Delta modulation simulation model (.rar file) is here at