Compute the group delays of the digital down converter using the groupDelay function.

Create a dsp.DigitalDownConverter System object with the default settings.

dwnConv = dsp.DigitalDownConverter

dwnConv = 
  dsp.DigitalDownConverter with properties:

           DecimationFactor: 100
         MinimumOrderDesign: true
                  Bandwidth: 200000
    StopbandFrequencySource: 'Auto'
             PassbandRipple: 0.1000
        StopbandAttenuation: 60
                 Oscillator: 'Sine wave'
            CenterFrequency: 14000000
                 SampleRate: 30000000

  Show all properties

Use the groupDelay function to compute the vector of group delays. By default, the function evaluates the group delays at 8192 frequency points equally spaced around the upper half of the unit circle.

D = groupDelay(dwnConv);

Plot the vector of group delays.

plot(D)
xlabel('Number of frequency points')
ylabel('Group delay')

Determine the vector of frequencies over which the group delays are computed and plot them.

[D,F] = groupDelay(dwnConv);
plot(F,D)
xlabel('Frequencies')
ylabel('Group delay')