CLIOwin 7 PCI User's Manual - Audiomatica

This is substantially the measurement of the frequency response of the CLIO board itself
which is, when calibrated, a straight line; as said in the cited procedure the acquired level
of such a measurement is -5.2 dBV. Let's see a practical way to acquire this level in order
to refer future measurements to it. Keep the instrument connected as in Fig.3.9, with
input A and output A short circuited. Press the MLS button to start generating the MLS
signal (the same signal that MLS uses during its operation). Press Go to start acquiring
this signal, you should read circa 0.54V. Also select the Slow integration as the MLS signal
is a wide band noise. While the measurement is running press the button; answering
yes to the warning message this will set the global reference level. To inspect the
captured value press the button's drop down menu. You should see the situation in
Fig.8.4.
Figure 8.4
The drop down tells you what the actual global reference level is. If you want to restore
the default, which is 1V, just choose Reset. Having completed this should you choose
dBRel as your units expect to read 0dBRel!
But let's go to the MLS control panel and see how we can reference frequency response
measurements. Open the MLS control panel and simply choose dBRel as units. Then
start the measurement. You should obtain the results as shown in Fig. 8.5; a general
tendency is always a straight line but now the reading is circa 0dBRel.
Figure 8.5
88 Chapter 8 - Multi-Meter