User`s manual

let us go back to the procedure described in 3.7.1 which aims at validating a
calibration. 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.3.29, 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
94 8 MULTI-METER