HP 3580A - IF Feedthru and Zero Beat Response Tests; Input Impedance Tests

Section V
PERFORMANCE TESTS
Model 3580A
Step e and f· 1000.48 kHz to 1000.52 kHz
Step e and f· 1000.98 kHz to 1001.02 kHz
Step e and f· 1001.48 kHz to 1001.52 kHz
e. With the FREQUENCY control pulled out for fine
tuning, tune the 3580A frequency for a Counter reading
between 1000.58 kHz and 1000.62 kHz.
f. Press CLEAR WRITE, then slowly turn the
MANUAL VERNIER to obtain a peak reading. The peak
should be more than 70 dB below full scale (- 140 dBV).
g. Repeat Steps e and f substituting 1001.18 kHz to
1001.22 kHz, and 1001.78 kHz to 1001.82 kHz for the
Counter readings.
DISPLAY SMOOTHING ........... MIN
FREQ.SPAN/DIV ................ 20 Hz
NOTE
If the instrument fails this test double check
that the input short is as small as possible; that
all power line cu"ent is kept at a minimum,
and that all covers are tightly secured on the
3580A.
5-36. IF Feedthru and Zero Beat Response Tests.
5-3 7. These tests verify the ability of the instrument to
reject a 100 kHz signal at the input and also how well the
Zero Beat Response is suppressed. Proceed to the Mixer
Balance Adjustments (Paragraph 5-81) of the Adjustment
Procedures if the Zero Beat Response is too large. Proceed
to Section VII for troubleshooting information if there is
too much IF Feedthru.
Equipment Required:
Frequency Synthesizer (-hp- Model 3320B, 50 ohm)
a. Reconnect the synthesizer to the 3580A. Do not
terminate. Adjust the source for a 10 volt 100 kHz output
(+ 26.99 dBm 50 ohms setting on 3320B and untermina-
ted).
b. Position the following front panel controls: (Only
those controls printed in BOLD require a change from the
previous test).
ADAPTIVE SWEEP ................. OFF
DISPLAY . . . . . . . . All pushbuttons released
AMPLITUDE MODE ...... LOG 10 dBv/DIV
AMPLITUDE REF LEVEL ....... NORMAL
dBv/LIN - dBm 600 n ............ dBv/LIN
INPUT SENSITIVITY ............. + 20 dB
VERNIER (Amplitude) . . . . . . . . . . . CAL
(Fully CW)
FREQUENCY ................. 00.0 kHz
START-CTR ................... START
RESOLUTION BANDWIDTH . . . . . . . . 3 Hz
DISPLAY SMOOTHING ........... MIN
5-12
FREQ. SPAN/DIV . . . . . . . . . . . . . . . . 20 Hz
SWEEP TIME/DIV . . . . . . . . . . . . . . . 5 SEC
SWEEP MODE ................. MANUAL
Option 002: Set dBm 900 Q/LIN -
dllm 600 n switch to dBm 900 n; set INPUT
MODE switch to UNBAL.
c. Adjust MANUAL VERNIER for a response in the
center of the screen. The display indication should be at
least 70 dB below full scale to verify the IF Feedthru
specification of Table 1-1. If the instrument fails this test,
see Section VII for troubleshooting information.
d. Disconnect the synthesizer. Reposition the following
front panel controls:
RESOLUTION BANDWIDTH . . . . . . 300 Hz
FREQ. SPAN/DIV ................ 5 KHz
SWEEP MODE ................... RESET
e. Momentarily press the following front panel control:
DISPLAY ............... CLEAR WRITE
f. Adjust ZERO CAL for a maximum display indication
on the left graticule. This display should be at least 30 dB
(3 major divisions) below full scale to verify the Zero Beat
Response specification of Table 1-1. If the instrument fails
this test, go to the Mixer Balance Adjustments (Paragraph
5-81) of the Adjustment Procedures.
5-38. Input Impedance Tests.
5-~. These tests verify the Input Impedance characteris-
tics of Table 1-2. Since there is no adjustment for this
parameter, see Section VII for troubleshootinginfcmnation
if the instrument fails this test.
Equipment required:
1 Mn ± 1 % film resistor (-hp- Part No. 0757-0344)
a. Position the following front panel controls. (Only
those controls printed in BOLD require a change from the
previous tests.)
ADAPTIVE SWEEP ................. OFF
DISPLAY ........ All pushbuttons released
AMPLITUDE MODE ...... LOG 10 dBv/DIV
AMPLITUDE REF LEVEL ....... NORMAL
dBv/LIN - dBm 600 n ............ dBv/LIN
INPUT SENSITIVITY .. . .. . .. .. . .. . 0 dB
VERNIER (Amplitude . . . . . . . . . . . . CAL
(Fully CW)
FREQUENCY ................. 00.0 kHz
START-CTR ................... START
DISPLAY SMOOTHING ............. MIN
RESOLUTION BANDWIDIB . . . . . . . 10 Hz
FREQ. SPAN/DIV ................ 1 KHz
SWEEP TIME/DIV . . . . . . . . . . . . . . . 5 SEC
SWEEP MODE ................... RESET