g. Check display
from 10 MHz to 12.4 GHz over 50 MHz dispersion on band A
Maximum amplitude
variation over 100 MHz window ( 50
and over 100 MHz dispersion for bands B and C to 12.4
MHz from RF center
frequency) must not exceed 3 dB. Ad-
GHz. 6 dB maximum amplitude variation from 12.4 GHz
just MIXER PEAKING
for maximum signal amplitude before
to 40 GHz, over 100 MHz dispersion.
measuring flatness.
NOTE
h. Remove the signal from band B INPUT and apply the
Display Flatness check for bands B and C must
output from signal generators, that cover scales 4 through
be made with the MIXER PEAKING control adjusted
6 frequency range, to band B Coaxial Mixer.
to maximize signal amplitude for each display
window.
i. Check response flatness through the frequency range
of the Coaxial Mixer. Maximum amplitude variation over
b. Set the front panel controls as follows:
100 MHx dispersion window must not exceed 3 dB. Adjust
MHz/DIV
DISPERSION RANGE
MIXER PEAKING for maximum signal amplitude before
measuring flatness.
5 MHz/div
DISPERSION
LIN
VERTICAL DISPLAY
j. Replace the Coaxial Mixer with the Waveguide Mixer
20 dB
IF
ATTENUATOR
Adapter.
A
Band Selector
k. Apply the output from a signal generator, within the
5 ms
TIME/DIV
frequency range of scale 8 and 9, through one of the Wave-
c. Apply the output signal from a signal generator with-
guide Mixers and the 2 foot cable (with TNC connectors)
in the frequency range of band A through a 20 dB attenu-
to band C Waveguide Adapter.
ator, (Part No. 011-0086-00) to the band A RF INPUT con-
l. Check response flatness for the frequency range above
nector.
12.4 GHz. Maximum amplitude variation over 100 MHz dis-
d. Set the generator frequency and
the RF center fre-
persion window must not exceed 6 dB (+2.4 div, -1.3 div).
quency to the frequencies that are listed
Adjust MIXER PEAKING for maximum signal amplitude
the signal generator output attenuator
and the Type 491
before checking flatness.
GAIN control for a signal amplitude of
6 divisions.
m. Remove the Waveguide Adapter and replace the
e. Check band A display flatness by tuning the signal
Coaxial Mixer in the band C receptacle.
from the left edge to the right edge of the display screen
with the RF CENTER FREQUENCY control. (Frequency range
+ and - 25 MHz from the RF center frequency.) Signal
amplitude should not change more than 1.5 dB from its
average amplitude or 3 dB (2.4 div) total.
System Sensitivity and Phase Lock Opera-
tion
RF Center
NOTE
Applied Signal
Frequency
Generator Freq.
Since signal generators with calibrated attenuators
10 MHz- 60 MHz
35 MHz
are required to check sensitivity, dial accuracy can
75 MHz
50 MHz-100 MHz
be checked by the same instruments provided the
signal source has an accuracy within 0.1% at the
125 MHz
100 MHz-150 MHz
dial check points. The signal generators listed in
175 MHZ
150 MHz-200 MHz
Table 5-7 may be
used if
accuracy is checked near
225 MHz
200 MHz-250 MHz
each dial check point, by a frequency counter or
275 MHz
250 MHz-275 MHz
the beat frequency indicator against some accurate
reference frequency.
f. Remove the signal to band A, RF INPUT and apply
A secondary or alternate source of accurate fre-
a signal within the frequency range of band B to RF INPUT
quency markers is the combination of two calibra-
B. Set the band selector to B and set the DISPERSION to
tion
fixtures
(Harmonic
Generator
067-0594-00
10 MHz/div.
and a 200 MHz Trap 067-0595-00) and a rela-
signal source such as a Time-Mark Generator
Applied
Signal
RF Center
(Type 184).
Frequency
Generator Freq.
The harmonic generatar will produce sufficient
275 MHz-375 MHz
325 MHz
harmonic signal power from the Type 184 to pro-
425 MHz
375 MHz-475 MHz
duce frequency markers into the GHz range. The
475 MHz-575 MHz
525 MHz
200 MHz trap attenuates the IF feedthrough spuri-
575 MHz-675 MHz
625 MHz
ous response.
725 MHz
675 MHz-775 MHz
This procedure is divided into two steps, with step
825 MHz
775 MHz-875 MHz
24B describing the dial check procedure using the
850 MHz
875 MHz-900 MHz
harmonic generator.
5-10