HP 8340B Manual page 78

4-16. FM ACCURACY AND FLATNESS (Cont'd)
9. Press [SHIFT] [CW] on the DUT. Note
activates the fine tuning feature on the DUT. The CW frequency will be displayed in the DUT's
ENTRY
DISPLAY.
STEP DOWN keys to place the flashing cursor just to the left of the decimal point. Turn the DUT's
rotary knob (changing the CW frequency) until the marker on the HP 3585A's CRT dips. (It is
normal for a spurious signal to be displayed below the actual marker. Keep turning the DUT's
knob until the marker dips.)
Press the
STEP UP
reaches minimum amplitude. This should be possible every 75 MHz or so due to the length of the
delay line.
Step 15 will instruct the operator to set the DUT's FM sensitivity to 10
MHz/V when performing step 10. If the HP 355D step attenuator has not
been set to 50 dB, the DUT's OVERMOD light will come on.
10. Move the output of the HP 8447F to the DUT's FM input. Turn FM ON and
DUT's FM sensitivity is set to 1 MHz/V (default condition).
Set the HP 3585A to 2 dB/DIV and turn A-B back ON. Press
11.
the HP 3585A's rotary knob (usually counter-clockwise) until the marker is on the center horizon-
tal graticule. If the OVER RANGE beep and message occur, turn the rotary knob in the opposite
direction. Don't be concerned if the marker does not move at first, it may take several complete
turns of the rotary knob before any change is noticed on the CRT.
12. Press [CONT]sweep on the HP 3585A. The spectrum analyzer will now display the FM flatness
from 50 kHz to 10 MHz.
The HP 3585A's marker offset feature can be used to display a digital readout of the signal power
level. The readout will be expressed relative to the power level at 100 kHz. To activate this feature,
press the following keys on the HP 3585A:
[MANUAL][1]
The power level at any chosen frequency between SO kHz and
power level) will be displayed in the upper right hand corner of the CRT. Turn the HP 3585A's
rotary knob to change the measurement frequency.
13. Determine the maximum and minimum deviation points from the 100 kHz reference. The dif-
ference between these points should be =3dB. Record the worst case power level on the Test
Record Card.
Repeat Steps 6 through 13 for frequencies of 2.5, 6.9,13.4, and
14.
proceed to step 15.
an HP 8340B, also perform the following: Press [CW] [2] [0] [GHz]. Repeat steps 6
If testing
through 13.
iS. Repeat Steps 6 through 14 with the HP 355D step attenuator set to SO dB. When repeating step 10,
set the FM sensitivity to 10 MHz/V, not 1 MHz/V.
HP 8340B/41B
Take note of the flashing cursor in the ENTRY DISPLAY. Press the STEP UP or
key twice. Turn the DUT's rotary knob until the marker on the HP 3585A
[01
[kHz] [OFFSET][ENTEROFFSET] [MARKER]
[0]
frequency shown in the ENTRY DISPLAY. This
the CW
NOTE
[CLEAR
Verify that the
AM OFF.
A]. Press [REFLVL] and turn
(relative to the 100 kHz
10 MHz
testing an HP 8341 B,
18 GHz. If
Performance Tests 4~-81/4-82