Filter Design Toolbox

Noise Loading Frequency Response Analysis: nlm

You can estimate the frequency response of the filter Hq you just created using the noise loading method computed with nlm. The noise loading method takes quantization effects into account. This method estimates the quantization noise figure when it runs a set of Monte Carlo frequency response calculations by filtering a set of sinusoids with randomly varying phase.

• nlm(Hq)
  
  
  
  

Difference Between nlm and freqz for Frequency Response Analysis

The frequency response computed by freqz is determined using the true linear frequency response of the transfer function associated with the quantized filter coefficients. It does not take any other quantization effects into account, and is not computed from the filter structure you specify.

The frequency response computed by nlm is an estimate of the frequency response that accounts for nonlinear quantization effects due to your choice of:

• Filter structure
• Other quantization parameters

Analyzing the Frequency Response with freqz

Analyzing Limit Cycles with limitcycle