QuantAsylum QA401 User
’s
Manual
Page
47
In the plot above, you can see the 19 KHz and 20 KHz tones applied at -7 dBFS, and the resultant mixing
product that shows up at 1 KHz, 2 KHz, etc. As the marker shows, the 1 KHz tone is roughly 100 dB below
the input tones, and thus the IMD shown is roughly 0.001%.
Another common IMD measurement is commonly known as the SMTPE IMD measurement. This
involves a low frequency signal (usually 60 Hz) and a high frequency tone (usually 7 KHz), with the lower
frequency being 4 times greater (12 dB). Below we see both tones.
