HP TM 11-6625-2779-14&P Performance Checks, Level Accuracy Checks, Function CARRIER, 75 Unbal

Section V Model 3555B

Figure 5-1. Balanced BNC to 310 Plug

function, remove or clip the shorting bar from across A1 R17 (see Figure 7-2).

b.Remove the 150 BAL decal from the small envelope supplied with the set and stick it over the existing 135 BAL decal.

c.Adjust the 150 function as described in Paragraph 5-20in this manual.

5-7. PERFORMANCE CHECKS.

5-8. The performance checks presented in this section are in-cabinet checks designed to compare the Model 3555B with its published specifications. These checks can be used for incoming inspection, periodic maintenance checks and to verify performance after adjustment or repair. A performance check test card appears at the end of this section which can be used to record the specification performance of your set.

5-9. LEVEL ACCURACY CHECKS.

a.Connect only the 654A and 3555B as shown in Figure 5-2and set the 3555B controls as follows:

FUNCTION	CARRIER, 75 UNBAL
INPUT	TMS, TERM
RANGE	+10dBm

b. Set the 654A frequency to 20kHz, IMPEDANCE to 75 UNBAL and adjust the output level for +10dBm. If the calibration of the 654A is questionable, first connect the output of the 654A through a 75 ohm termination, directly to the input of the 3440A/3445A (3555B not connected) and measure the voltage. This level should be 866mV rms. If it is not, adjust the 654A amplitude control until it is and note the 654A meter indication for future reference. Now that the 654A calibration has been verified, disconnect

Figure 5-2. Level Accuracy Check

5-2