Slope/Integrating ADC in Matlab Simulink

Response to: ADC in Matlab simulink:

The first time I did this I misinterpreted the question, posting a sigma-delta example rather than an integrating (slope) ADC. Anyway, here’s a slope ADC starting point:

simulinkslopeadc

Here’s a plot of the input (with an offset) and the integration of the input:

Upper plot showing sinusoid with offset; lower plot integrator-with-reset of the upper

Here’s a plot of the control signal (reset signal on the integrator; active low):

Control signal (output of comparator) has a period proportionate with input signal

Control signal (output of comparator) has a period proportionate with input signal

From this, the counter logic should be easy: simply run a counter that resets itself with the control signal. You can pretty much use the integrator inside the ADC itself as a template for this.

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2 Comments

  1. krishna kumar
    Posted January 27, 2010 at 9:52 pm | Permalink

    I am looking for matlab and simulink code for decimation filter.
    The input to the decimation filter is bitstream 11.3Mhz and output should be 16bit at Nyquist rate. Please help me with the code. I have not designed it before.
    Thanks,
    K.K

    • Posted February 16, 2010 at 12:46 am | Permalink

      Hi, Krishna.

      What you’ve stated isn’t fully specified. You say the input is 11.3 MHz, but what’s the output (or signal bandwidth)? What format is the input (PCM, floating point)?
      When you say 16-bit, do you mean quantization noise, or aliasing, or both?
      I can help you with a procedure, but I don’t have Simulink, so I can’t really give you an end solution.

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