A
RF Band Selector
Hewlett-Packard MX292B Wave-guide to coaxial adapter.
Centered (5 turns from
FINE RF CENTER FREQ
Hewlett-Packard MP 292B Wave-guide to coaxial adapter.
either extreme)
Hewlett-Packard NK292A Wave-guide to coaxial adapter.
MIXER PEAKING
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Hewlett-Packard 11503A flexible wave-guide.
Phase Lock Controls
Hewlett-Packard 11504A flexible wave-guide,
INT REF FREQ
OFF
PERFORMANCE CHECK PROCEDURE
1. Trace Alignment
General
a. Requirement--Horizontal trace alignment is not criti-
In the following procedure, test equipment connections or
cal and is usually set to the operator's requirement, If mis-
control settings should not be changed except as noted. If
alignment is excessive (approximately 2) refer to the Cali-
only a partial check is desired, refer to the preceding step(s)
bration Section.
for setup information.
The following procedure uses the equipment listed under
2. Astigmatism
Recommended Equipment. If substitute equipment is used,
control settings or setup must be altered to the require-
a. Requirement--Well defined display with equally fo-
ments of the equipment used.
cused vertical and horizontal segments in the display.
Several checks use a 200 MHz signal applied to the RF
b. Adjust the GAIN control for a display with approxi-
INPUT connector. This IF feedthrough signal is not tunable
mately 1 division of noise.
with the RF center frequency. To avoid interference from
c. Adjust the FOCUS control for optimum focus, then
other signals it is recommended that the tunable signals be
adjust the ASTIGMATISM control for optimum vertical def-
positioned off the screen with the RF CENTER FREQUENCY
inition. Display should be well defined with optimum setting
control.
of the FOCUS control.
Preliminary Procedure
3. Scale Illumination
Connect the instrument to a power source within the reg-
a.
Requirement-Graticule
scale
illumination
must
vary
ulating range of the Type 491. Turn the POWER switch to
smoothly from no illumination with the SCALE ILLUM control
ON and allow at least 20 minutes warm up time at 25 C
fully counterclockwise to maximum illumination with the con-
5 C before checking the instrument to given accuracy.
trol fully clockwise.
Set the front panel controls as follows:
b. Rotate the SCALE ILLUM control from a fully counter-
clockwise position to full clockwise.
INTENSITY
Nominal
brightness
Adjusted for a sharply
FOCUS and
c. Illumination must increase smoothly as the control is
focused display
ASTIGMATISM
rotated,
Position the trace to the
POSITION
bottom graticule line and
center horizontally
4. Position Controls
1 ms
TIME/DIV
a. Requirement--Vertical P O S I T I O N c o n t r o l m u s t p o s i -
CAL
VARIABLE
tion the sweep beyond the upper and lower graticule limits,
SLOPE
+
Horizontal POSITION control must position either end of the
FREE RUN
LEVEL
sweep into the graticule area.
INT
SOURCE
b. Rotate the Vertical POSITION control to both extremes.
Note that the range of the control equals or exceeds the
Dispersion Controls
requirements in step a.
MHz/DIV
DISPERSION
RANGE
c. Rotate the Horizontal POSITION control to both ex-
10 (MHz/div)
DISPERSION-COUPLED
tremes. Note that the range of the control equals or exceeds
RESOLUTION
the above requirements.
All switches OFF
IF ATTENUATOR dB
IF CENTER FREQ Controls
5. Check Sweep Length
Midrange (000)
IF CENTER FREQ
a. Requirement--Sweep Length must equal 10.5 divisions
Midrange
FINE
0.2 divisions.
VIDEO FILTER
OFF
b. Check the above requirements for the sweep length.
LIN
VERTICAL DISPLAY
5-2
