QuantAsylum QA401 User
’s
Manual
Page
46
The amplitude of the generator will always be specified in the current units of display. For example, if
you have specified dBV, then the amplitude you enter will be in dBV units. When you switch to another
units (such as dBFS), then value you entered will automatically be converted to the new units.
The frequency and amplitude knob sensitivities allow you to specify how much each value will change
when you rotate your mouse wheel above the Freq and Amp knobs. And again, if you press the control
key while adjusting the knob, the knob will spin 10X faster. And if you press the shift key while adjusting
the knob, the knob will spin 10X slower.
IMD Measurements
The primary purpose of the dual-tone generators is to permit IMD measurements. While the QA401
doesn’t perform automatic IMD measurements, they are easy to perform manually. A typical IMD
test
would be the IMD ITU-R test. This requires applying two tones of equal amplitude spaced 1 KHz apart.
Usually, the tones are 19 KHz and 20 KHz.
