User's Manual

TB8100 Calibration Kit User’s Manual Audio Calibration 19
To calibrate the balanced input and output lines
1. Ensure that the Calibration Kit PC is connected to the reciter.
2. Select the Reciter Calibration tab, and double-click Balanced Line
Calibration. The Balanced Line Calibration Wizard appears.
3. Attach an AC millivoltmeter and terminate the balanced output in 600
ohms (either using the load on the CTU or looping the balanced output to
the balanced input), and then click Next.
4. Adjust the slider in the dialog box until the audio level on the millivoltmeter
reads 1 V
PP (0.354 VRMS).
Note: Click Coarse to roughly adjust the audio level, and once you
get within range, click Fine for more precise control over the
settings. To move up or down 10 mV
PP, click either side of the
slider bar.
5. Click Next. The balanced output is now calibrated.
6. Note the level of the AC millivoltmeter, and then turn off the 600 ohm
load.
7. Connect the balanced output to the balanced input. Verify that the
millivoltmeter reading is substantially unchanged. (This confirms that the
input provides a 600 ohm impedance.)
8. Click Finish. The balanced input is now calibrated.
When you have finished calibrating the balanced lines, the icon on the
Reciter Calibration tab indicates that this task is complete.
Calibrating the Unbalanced Lines
Calibrating the unbalanced lines adjusts their gain, so that when you set line
levels using the TB8100 Service Kit software, the actual line level correctly
reflects the Service Kit settings. (Refer to the TB8100 Service Kit User’s Manual
for further information.)
Equipment ■ CTU
■ AC millivoltmeter
Setup for
Unbalanced Line
Out
1
6
3
4
2
5
1 Reciter 3 CTU 5 Unbalanced line output
2 25-way cable 4 System interface port 6 AC millivoltmeter