QuantAsylum QA401 User
’s
Manual
Page
40
THD + N
The THD + N measurement is enabled using the button on the panel. THD+N is similar to the THD
measurement, but instead of looking at just the harmonic power, all of the non-fundamental power is
considered in the specified bandwidth.
Notice the relationship between the highlighted numbers above. The peak value is -10 dBV (which is the
level of the signal generator), and Noise + Distortion is measured as -95.5 dBV, and thus this means the
ratio of the signal to the noise and distortion is -85.5 dB, which is what is reported in the THD+N
calculation.
Frequency Response
The QA401 offers a quick way to look at the frequency response of a device under test (DUT). This is
achieved with the Frequency Response (FR) button. The context menu for the Frequency Response
button appears as follows:
