Fixed Equalization for Two-channel Measurements

Fixed Equalization allows you to reduce the difference between the two measurement channels in your measurement. Without corrections, the effects of the cabling, connectors, and coupler/splitters, as well as differences between Ch1 and Ch2 in the instrument, will be included in the measurement results.

Here is an example of using fixed equalization for a stimulus-response measurement with a 2-channel instrument.

  1. Connect a pass-through connector in place of the DUT Device under Test: An acronym used to describe some type of electrical apparatus connected to test instrumentation. The apparatus can range from a single component to a complex subsystem such as a mobile phone, base station or MSC..

  2. Connect a wide-band signal via a splitter to channel 1 and to the pass-through connector.

    The signal must have energy (on average) throughout the band of frequencies for equalization. The best signals are white noise, chirps, or noise-like digitally modulated signals. They need not be periodic.

  3. Make an RMS-averaged, Vector measurement.

  4. View the Coherence trace. The coherence should be close to 1 across the span. Coherence usually increases with the number of averages. If it is consistently low in some portions of the span, the signal may need to be changed so that it has energy in these areas.

  5. View the Frequency response trace and save it to data register D1 (File > Copy Trace).

  6. Enable Fixed Equalization

    1. In the Fixed Equalization tab, select the Fixed Equalization check box
    2. Select Meaurement Channel 2

    3. Set Register to D1.

    (Or equivalently, you could select Measurement Channel 1, Register D1, and Invert.)

See Also

Fixed Equalization Tab