Calibration—492/492P Service Vol. 1 (SN B030000 & up)
Performance Check
d.
Activate AF. Adjust the FREQUENCY so the 2nd mul
tiple of the input frequency is centered. Increase the REF
LEVEL to -5 0 dBm, decrease the FREQ SPAN/DIV to
500 kHz and the RESOLUTION BANDWIDTH to 10 kHz.
e.
If your instrument has Option 03, decrease the FREQ
SPAN/DIV to 1 kHz and the RESOLUTION BANDWIDTH to
100 Hz. Check the amplitude of the noise sidebands 3 kHz
away from the signal. Noise sidebands should be 70 dB be
low the signal level or 50 dB below the top of the screen.
e. Check the display for harmonic spurii (spurious re
sponses) of the input signal. Harmonic spurii must be down
60 dB or more from the -3 0 dBm carrier (-4 0 dB below
top of screen).
f. Increase the FREQUENCY to the 3rd harmonic. Check
for harmonic spurii. Again responses must be down 40 dB
from the top of the screen (60 dBc).
g. If the instrument has Option 01 and Option 03, in
crease the REF LEVEL to —70 dBm, decrease the FREQ
SPAN/DIV to 2 kHz and the RESOLUTION BANDWIDTH to
100 Hz. Deactivate the Video WIDE Filter. Check that har
monic spurii are 100 dB or more down from the —30 dBm
carrier level.
19. Check Noise Sidebands (—75 dBc or more at
30 times the resolution bandwidth offset, fundamental
mixing, Option 03 is —70 dBc for 100 Hz resolution
bandwidth)
a. Set the front-panel controls as follows:
FREQUENCY RANGE
FREQ SPAN/DIV
Vertical Display
TIME/DIV
REF LEVEL
AUTO RESOLUTION
VIDEO FILTER
Digital Storage
(Option 02)
Band 1
20 MHz
10 dB/DIV
AUTO
- 2 0 dBm
On
WIDE
VIEW A/VIEW B
b. Apply the CAL OUT signal to the RF INPUT. Center
one of the markers on screen with the FREQUENCY control
and adjust the REF LEVEL for a full screen display.
c. Keep the calibrator marker centered on screen as the
FREQ SPAN/DIV is reduced to 10 kHz and the RESOLU
TION BANDWIDTH is decreased to 1 kHz. If Option 03 is
installed, note that phaselock is operative.
d. Increase the REF LEVEL 20 dB to —40 dBm to posi
tion the signal peak 20 dB above the
reference
line. Check
the amplitude of the noise sidebands 30 times the resolution
bandwidth away from the signal (see Fig. 3-16). Noise
sidebands should be 75 dB or more below the peak signal
level or 55 dB below the top of the screen.
20. Check Residual Response ( < — 100 dBm)
a. Remove all signals to the RF INPUT and set the front-
panel controls as follows:
FREQUENCY
FREQ SPAN/DIV
REF LEVEL
MIN RF ATTEN
RESOLUTION
BANDWIDTH
TIME/DIV
Vertical Display
Bands 1 —3
(100 kHz— 7.1 GHz)
10 MHz
—50 dBm
OdB
10 kHz
AUTO
10 dB/DIV
Digital Storage (Option 02)
VIEW A/VIEW B
b.
Scan the frequency range of bands 1, 2, or 3 in
100 MHz increments. Note the amplitude of any spurious
response. Spurii amplitude must not exceed —100 dBm.
(By activating AF after each increment, it is easier to deter
mine 100 MHz increments.)
Si
j
0
\
do
nl
\ 2 _
I0KH
—
m
Z '- .
I
25__
I
r
-20
___ I
I
L
j
=Τ..3Λ .KHz
-M
H__ j
J s
Γ
___
I
•(I
T
I
-se
7
j
Λ
: Noise downj
3* 75 dB
g V i g l
o
m
. . . u i
j B _
□ Lu
Fig. 3-16. Typical display of phaselock noise.
3-30
REV AUG 1981
