The View / Frequency Response commands create plots of the FIR filter frequency responses. You can view the frequency responses of each of the project's filters:

• The Inphase (I) Filter, taken as a single real filter.
• The Quadrature (Q) Filter, taken as a single real filter.
• The Inphase and Quadrature (I and Q) Filters: the response of the I and Q filters taken as two separate real filters, shown as two curves on the same plot.
• The Complex Filter: the response of the I and Q filters taken together as a single Complex filter.

ScopeFIR can plot the following frequency responses:

• Magnitude: the magnitude response of the selected filter.
• Phase : the phase response of the selected filter.
• Unwrapped Phase: the phase resonse of the selected filters after "unwrapping" discontinuities which occur as the phase angle wraps around the circle. This plot typically shows a long straight line in the passband(s), and a series of shorter "sawtooths" in the stopband(s).
• Group Delay : the group delay of the selected filter. Group Delay (sometimes called "Envelope Delay") is defined as the negative of the deriviative of the (unwrapped) phase with respect to frequency. For a linear-phase filter, Group Delay represents the overall delay of a signal through the filter.
• Phase Delay : the phase delay of the selected filter. Phase Delay is the negative of the (unwrapped) phase divided by the frequency.

After you have created a plot with a View command, you can change your selections of filter and response type which appear in the plot. Simply select the plot window by clicking on it with the left mouse button, then use either the Frequency menu at the top, or right-click the mouse to get a dropdown ("context") menu. These menus allow you to select a different filter and/or response to be plotted.