The Simple Parks-McClellan Editor edits specifications for equiripple FIR filters having a single passband or stopband. It can be used to design simple lowpass, highpass, bandpass, or bandstop filters. The Simple PM Editor looks like:

To design a filter:

• Specify the sampling frequency by hitting the Sampling Frequency button in the upper left. You will be prompted to enter the numerical frequency and the units of frequency/time.
• Specify the number of taps, if known; otherwise, come back to this after entering other specifications.
• Specify Grid, the design grid density. Generally, the default value of 16 works well and does not have to be changed. (See the Advanced Parks-McClellan Specification Editor section for more information on grid density.)
• Select a Filter Type: Lowpass, Highpass, Bandpass, or Bandstop. If you select Bandpass or Bandstop, enter the center frequency of the passband or stopband.
• Enter the filter Specifications. You will always enter the Passband Ripple in dB and the Stopband Attenuation in dB, but the prompts for the other required Specifications vary according to the Filter Type:
• For Lowpass filters, enter the Passband Upper Frequency. (The Passband Lower Frequency will always be zero.) Enter the Stopband Lower Frequency. (The Stopband Upper Frequency will always be Fs/2.)
• For Highpass filters, enter the Passband Lower Frequency. The Passband Upper Frequency will always be Fs/2.) Enter the Stopband Upper Frequency. (The Stopband Lower Frequency will always be zero.)
• For Bandpass filters, enter the Passband Bandwidth at Top. This is the width of the center part or "nose" of the passband. Enter the Passband Bandwidth at Bottom. This is the width of the passband as it touches the stopbands. (The Passband Bandwidth at Top must necessarily be smaller than the Passband Bandwidth at Bottom.) Enter the Bandpass Center.
• For Bandstop filters, enter the Bandstop Bandwidth at Top. This is the width of the bandstop notch as it touches the passbands. Enter the Bandstop Bandwidth at Bottom. This is the width of the bandstop notch as it touches the stopbands. (The Bandstop Bandwidth at Top will always be larger than the Bandstop Bandwidth at Bottom.) Enter the Bandstop Center.
• Having entered all Specifications you may hit the Estimate button to estimate the number of taps. (Note that ScopeFIR can estimate Lowpass and Highpass filters but not Bandpass and Bandstop filters.)
• Hit the Design or Optimize button to design your filter. If the design process is successful, the actual passband ripple and stopband attenuation will appear. If the filter does not meet specifications, you can increase the number of taps and try again; likewise, if the filter far exceeds specifications, you can try reducing the number of taps.