Hello!

I can not figure out the implementation of DPCM in a digital system. I have an 8-bit ADC, the output of which is a digital signal (discretized and quantized) - this is PCM. I don’t know how to make DPCM from PCM.

My questions are as shown below:

1. In the diagram below, there is a quantizer - why is it needed if the signal is already quantized before it?
2. Also, I do not quite understand what a predictor is. In some sources, this is a simple one-measure delay line (sample).
3. What method can be used in the entropy encoder for compression?

Spoiler: DPCM Scheme

Thanks for attention!
I use google translator.

 

Hello!

I can not figure out the implementation of DPCM in a digital system. I have an 8-bit ADC, the output of which is a digital signal (discretized and quantized) - this is PCM. I don’t know how to make DPCM from PCM.

My questions are as shown below:

1. In the diagram below, there is a quantizer - why is it needed if the signal is already quantized before it?
2. Also, I do not quite understand what a predictor is. In some sources, this is a simple one-measure delay line (sample).

3. What method can be used in the entropy encoder for compression?

Spoiler: DPCM Scheme

View attachment 183321

Thanks for attention!
I use google translator.

It's all here:
https://en.wikipedia.org/wiki/Differential_pulse-code_modulation

 

What is the entropy coding algorithm (Q in scheme1/scheme2)?

Spoiler: Scheme1

Spoiler: Scheme2

 

What is the entropy coding algorithm (Q in scheme1/scheme2)?

Spoiler: Scheme1

Spoiler: Scheme2

This looks like homework. We do not do homework for students.
If you can show us what you think the answer is, we can maybe help you.

 

If you can show us what you think the answer is, we can maybe help you.

I will try to communicate in order to be understood!

I have assembled such a circuit according to the model (see Pic. #1).
So that at the output of the DPC modulator there would be at least 1 bit less (taking into account the sign bit) than with ordinary PCM, I had to increase the sampling frequency by 10 times! Explanations on the chart (see Pic. #2).

Spoiler: Pic. #1

Spoiler: Pic. #2

In this scheme, I did not add an entropy encoder, because I don’t know what formula should be encoded. Where could I be wrong? Although it seems to me that everywhere.

 

Is this a homework ?

 

Is this a homework ?

No, this is not homework. However, this question arose in the process of studying additional materials on the subject.

 

No, this is not homework. However, this question arose in the process of studying additional materials on the subject.

In this forum, anything that pertains to the formal study of a subject is classified as "Homework".