QuantAsylum QA401 User
’s
Manual
Page
11
X32 and X64 Installation
The drivers are signed, and on Windows 7 and later the installer will be able to auto-install the USB
drivers. This means that if you install the program and drivers, and then run the program and then plug
in the analyzer, everything should be taken care of automatically.
Calibration
The QA400 product, which was the predecessor to the QA401, required calibration by the user. This was
because the manufacturing window of the parts used could be fairly large (+/-25%). The QA401,
however doesn’t need calibration and will deliver outstandin
g accuracy out of the box.
Verifying Calibration
Calibration should be verified from time to time. The procedure is simple and requires a DVM with
trusted accuracy. Generally, quality DVMs will hold their stated accuracy for a decade or more easily,
because the drift and aging associated with the internal references used are very low. But quality DVM
manufacturers will also allow you send in your DVM and have it re-calibrated certified to be operating
correctly for a fee.
Using a DVM with a calibration that you trust, perform the following steps:
1)
Use the Settings
→
Generate Fixed Tone menu option to generate a 0 dBV signal at 60 Hz. Note
the amplitude. It should be 1.0/- 4% (0.96 to 1.04Vrms) on all 4 output ports of the
QA401. This is a single-ended measurement, with one input to the DVM taken from the center
of the BNC, and the other input to the DVM taken from the BCN outer conductor.
2)
Repeat the measurement used in step 1), except this time generate a 1 KHz signal. Most DVMs
will show a very small reduction in reading (few %) between 60 Hz and 1 KHz. This is attributable
to the natural roll-
off of the meter’s response. If your DVM shows more roll
-off than a % or two,
then make a mental note that your DVM is not suitable for direct measurements at 1 KHz and
the calculations below should be adjusted accordingly. Most meters are specified at 60 Hz, and
the upper corner isn’t generally published by the DVM manufacturers. Thus, it’s important to
know.
3)
Cancel the fixed tone generation and connect the + output L of the QA401 to the + input L of the
QA401. Short the
–
input.
4)
Select File
→
Reset startup defaults. This will put the analyzer into a known state.
5)
Set windowing to Flat Top, Atten Off, RMS Measurement, and dBV axis settings
6)
Set Gen1 to 1 KHz, 0 dBV
7)
Verify the input PeakL is 0 dBV +/- 0.1 dB
8)
Apply the attenuator. Verify the signal is 0 dBV +/- 0.15 dB.
9)
Activate the Right Channel and turn off the Left channel in the Display Options section of the UI.
Repeat the above steps for the right channel.
To verify the attenuator is working as expected, perform the following steps:
