Experiment：We design an IIR filter in Matlab，then the filter is transplanted to Sigmastudio，However the Magnitude Responses obtained by Matlab and Sigmastudio are different。Why？

The Detailed operations are as following.

Step 1：Define the characteristics of IIR filter in Matlab as 4 order, 1024 sampling rate, 300Hz frequency-pass and 400Hz frequency-stop.

Figure 1

Step 2：The magnitude response obtained in Matlab as Figure 2.

Figure 2

Though observing the figure 2，we find that the obtained magnitude response is consistent with the characteristics defined in Step 1.

Step 3： Export the coefficients from the Matlab。

图3

Step 4: Design the program in Sigmastudio，as figure 4.

Figure 4

Step 5：Import the coefficients (obtained in Step 3) into the IIR filter of Sigmastudio.

Figure 5

Step 6. The magnitude response obtained by SigmaStudio is as Figure 6 shown.

Figure 6

The coefficients used by Sigmastudio and Matlab are the same，however the obtained magnitude response figures are different. Why? Could you explain it detail.

Hello,

Your sample rate in Matlab appears to be 1024 Hz.

The default sample rate in SIgmaStudio is 48 kHz. You'll have to change the sample rate in SigmaStudio using these steps: http://ez.analog.com/docs/DOC-1431

Also note that most SigmaDSPs can only run at 48 kHz, 96 kHz, or 192 kHz sample rates.