Question

1.) when using the standard MATLAB commands, or the design equations, to design an FIR filter Why is it a good idea to check if the design, meets requirements 2 answer specificly.

Answer 1

Specify the filter further using a set of Name,Value pairs. The allowed specification sets depend on the response type, resp, and consist of combinations of the following:

• Frequency constraints correspond to the frequencies at which a filter exhibits a desired behavior. Examples include 'PassbandFrequency' and 'CutoffFrequency'. (See the complete list under Name-Value Pair Arguments.) You must always specify the frequency constraints.

• Magnitude constraints describe the filter behavior at particular frequency ranges. Examples include 'PassbandRipple' and 'StopbandAttenuation'. (See the complete list under Name-Value Pair Arguments.) designfilt provides default values for magnitude constraints left unspecified. In arbitrary-magnitude designs you must always specify the vectors of desired amplitudes.

• 'FilterOrder'. Some design methods let you specify the order. Others produce minimum-order designs. That is, they generate the smallest filters that satisfy the specified constraints.

• 'DesignMethod' is the algorithm used to design the filter. Examples include constrained least squares ('cls') and Kaiser windowing ('kaiserwin'). For some specification sets, there are multiple design methods available to choose from. In other cases, you can use only one method to meet the desired specifications.

• Design options are parameters specific to a given design method. Examples include 'Window' for the 'window' method and optimization 'Weights' for arbitrary-magnitude equiripple designs. (See the complete list under Name-Value Pair Arguments.) designfilt provides default values for design options left unspecified.

• 'SampleRate' is the frequency at which the filter operates. designfilt has a default sample rate of 2 Hz. Using this value is equivalent to working with normalized frequencies.

• IMPORTANTLY:

  If you specify an incomplete or inconsistent set of name-value pairs at the command line, designfilt offers to open a Filter Design Assistant. The assistant helps you design the filter and pastes the corrected MATLAB^® code on the command line.

  If you call designfilt from a script or function with an incorrect set of specifications, designfilt issues an error message with a link to open a Filter Design Assistant. The assistant helps you design the filter, comments out the faulty code in the function or script, and pastes the corrected MATLAB code on the next line