HP 654A - 5-36. Hum and Noise Check

Section V Model 654A
e. Adjust the wave analyzer to the same frequency as
the 654A and for a meter indication of between
-7dB and + 3dB.
f. Adjust the tracking oscillator SCALE OFFSET
control for a meter indication of OdB reference
level.
g.
Check the 654A 10dB attenuator at each position
by decreasing attenuation on the external
attenuator as attenuation is increased on the 654A
attenuator; at each position the tracking oscillator
meter indication should be OdB, +/- 0.15dB.
h. Check the 654A 10dB attenuator at 10MHz using
the following procedure.
1) Set the 654A to 10MHz.
2) Repeat steps d, e and f of this paragraph.
3) Repeat step g of this paragraph for the + 10
through - 60dB position of the 654A attenuator.
4) Repeat step g for the - 70 and - 80 positions of
the 654A attenuators except that the tracking
oscillator meter indication for these two
positions should be OdB, +/- 1dB.
NOTE
This procedure, so far, has checked only
one side of the attenuator, the following
step describes how to check the other
side.
i. Check the other side of the 654A 10dB attenuator
at 300kHz and 10MHz by interchanging the two
cables connected to the 654A output connectors
(i.e. as viewed in Figure 5-6, the cable terminated
in 75 ohms is moved with the termination to the
right-hand connector and the cable connected to
the 75 ohm to 50 ohm impedance converter is
moved with the converter to the left-hand con-
nector); then repeat steps c through h of this
paragraph.
5-27. 1 dB- STEP ATTENUATOR CHECK.
NOTE
See Paragraphs 5-24 and 5-25 before
making this check.
a. Connect the equipment shown in Figure 5-6
except use the 1 dB/step external attenuator and
do not use an external amplifier.
b. Perform steps b and c of Paragraph 5-26.
c. Set the external attenuator to the - 9dB position.
d. Perform steps e and f of Paragraph 5-26.
e. Check the 654A 1dB step attenuator at each
position by decreasing attenuation on the external
attenuator as attenuation is increased on the 654A
attenuator; at each position the tracking oscillator
meter indication should be OdB, +/- 0.15dB.
f. Repeat the check with the 654A and wave
analyzer set to 10MHz to verify the attenuator
accuracy at high frequency.
NOTE
This procedure, so far, has checked only
one side of the attenuator, the following
step describes how to check the
remaining half.
g. Check the other side of the 654A 1 dB step
attenuator at 300kHz and 10MHz by
interchanging the cables ( as described in Paragraph
5-26, step i) and repeating steps b through f of this
paragraph ( 5-27).
5-28. BALANCE CHECKS.
5-29. If the tolerances given in the following procedures
CONNECTOR
hp PART NO.
12 50-0052
RI
CONNECTOR
hp PART NO.
1250-008 3
Th
son
CONNECTOR
hp PART NO.
11048-27603
R2
THREADED SLEEVE
hp PART NO.
11048-27604
653A-8-17
7511
RI
43.311
R2
86.60
son
7511 TO 500 CONVERTER
750*
43.20 ± 1% I/8W
RI hp PART NO.
0757-0392
86.60 ± I% I/8W
R2
hp PART NO.
0698-4398
Figure 5-7. Impedance Converter
5-8