I have a cascade of two BJT transistors, and I'm trying to make the gain be within a certain range. I am using PSPICE and I'm not sure how to tell what the gain is at a certain frequency. How do I check?
The voltage gain is simply the output voltage over the input voltage.
A = Vout/Vin
There are several ways you can do it in PSPICE. You can input a given frequency and watch the response of the circuit over a given period of time. Compare the magnitude of the output signal to the input signal.
A second way to do it is to perform an AC Sweep. It allows you to select a beginning frequency, an end frequency, and number of points you would like to simulate. A graph of the output can be plotted to show the gain.
Here is a website that shows have to do it in one version of SPICE. Yours may or may not be similar but it might help a little.