QuantAsylum QA401 User
’s
Manual
Page
21
Axis
The axis controls select our units for the Y axis, and allow us to adjust the X and Y axis settings. Below we
see this control groups. The top 3 buttons set our Y Axis units. The dBFS button shows absolute units
relative to the ADC and DAC maximum output levels.
dBFS, dBV, and dBr Buttons
The dBV button shows our levels in absolute RMS voltage levels relative to 1Vrms.
And the dBR button allows us to display arbitrary levels relative to whatever we pick as a reference.
Since the dBFS levels are absolute, there is no adjustments to be made via context menu.
dBV Context Menu
The dBV levels are also absolute, but in dBV mode we can specify whether or not external gains are
attached to the inputs and outputs, and we can also opt to render the peaks in watts if we specify the
impedance connected.
Note that input gains will adjust all displayed data upwards the gain amount. In other words, if you
specify that you have a 0 dB external gain, then 1Vrms signal will be reported as 0 dBV. But if you specify
that you have a 10 dB external gain, then that same 1Vrms signal will be reported at 10 dBV. For both
input and output external gains, the correct way to think about the settings is that if you have non-zero
