HP TM 11-6625-2779-14&P manual Return Loss Check

Section V Model 3555B

Figure 5-3. +20dBm and +30dBm Level Accuracy Check

5-10. RETURN LOSS CHECK.

a.To make a return loss check it will first be necessary to construct a balanced bridge utilizing 0.1% resistors for each of the four 3555B impedances. Figure 5-4shows the equipment test set-up to be used. For this check to be meaningful, all test leads should be kept short. The leads connecting the 3555B to the bridge should be short clip leads and should be kept away from each other and from other leads. Keep all the instruments away from other instruments that may be referenced to earth ground.

b.Connect the equipment as shown in Figure

5-4and set the 3555B controls as follows:

FUNCTION	VF/Nm, 600 BAL
INPUT	TMS, TERM
RANGE	0dBm

NOTE

The 3555B does not have to be turned on for this check. If at any frequency the 3555B return loss check is out of specification, check the reference at that frequency as

described in the following procedure.

c. Set the 654A frequency to 1kHz. Temporarily close S1 in Figure 5-4and adjust the 654A output level for an up scale indication on the 400FL AC Voltmeter.

Table 5-4. VF/Nm Level Accuracy Checks 600 BAL and 900 BAL

-80dBm through +30dBm

RANGE	20Hz to 20kHz		40Hz to 15kHz		100Hz to 20kHz	100Hz to 15kHz
+30dBm					+30 ±0.5	+30 ±0.2
+20dBm					+20 ±0.5	+20 ±0.2
+10dBm					+10 ±0.5	+10 ±0.2
0dBm	0	±0.5	0	±0.2
-10dBm	-10 ±0.5		-10 ±0.2
-20dBm	-20 ±0.5		-20 ±0.2
-30dBm	-30 ±0.5		-30 ±0.2
-40dBm	-40 ±0.5		40	±0.2
-50dBm	-50 ±0.5		-50	±0.2
-60dBm	-60	±0.5	-60	±0.2
-70dBm	-70	±0.5
-80dBm	-80	±0.5

5-4