The following diagram shows a simple test setup used to measure the audio frequency response of a device:
Test setup to measure the audio frequency response
In the preceding diagram, the device is shown as an amplifier, but it could just as easily be an active or passive filter, for example a speaker cross-over network.
In any case, the basic technique is the same. What you do is set up so that the time for one sweep and the time base of the oscilloscope are the same. This means one sweep covers the full width of the oscilloscope screen.
You hook the test as shown and sweep away. You may have to play with the sweep times and the oscilloscope time base to get an accurate display. Unless you can find a generator program with a logarithmic sweep, the entire response might not fit on one screen. You may have to sweep the test circuit in bands such as high, low, and mid-range in the case of a simple speaker crossover network mentioned earlier.
