Tektronix 1L30, Инструкция по эксплуатации

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Performance Check—-Type 1L30
DISPERSION RANGE
DISPERSION-COUPLED
RESOLUTION
G A IN
VERTICAL DISPLAY
IF ATTEN dB Selectors
M H z /C M
2 M H z
Adjusted for a full
screen display
LIN
O ff
d. Center the display with the IF CENTER FREQ controls.
See Fig. 5-4A. Set the Time/Cm selector to 50 ms.
e. Switch the VIDEO FILTER switch to O N position. Note
the action of the video filter circuit on the display. Display
should resemble Fig. 5-4B, with most of the noise reduced
or eliminated.
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(A)
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(B) VIDEO FILTER' removes the noise and retains'the display
envelope.
c. Set the DISPERSION to 1 M H z/cm and the Time/Cm
to 5 ms positions. Switch the VERTICAL DISPLAY to LOG.
d. Align the I /is markers to the graticule lines with the
IF CENTER FREQ control. If necessary, adjust the DISP CAL
to calibrate the display. Note the displacement of the 9th
marker at the 9th graticule line.
e. Remove the Time-Mark Generator signals and apply
the T M Hz CAL MARKERS O UT signal to the RF INPUT. Ad­
just the G A IN control, if required, for a satisfactory 1 M Hz
marker amplitude and turn the RF CENTER FREQ control
to align the tunable markers with the fixed markers.
f. Check the frequency of the Internal Reference oscil­
lator by aligning the 1st marker with the 1st graticule line
and noting the displacement of the 9th marker from the
9th graticule line. There should be no noticeable difference
in the position of the marker from the position noted in
step e.
g. Remove the cable between the 1 M H z CAL MARKERS
O UT connectors and the RF INPUT connector. Turn the INT
1 M H z REF FREQ switch to the OFF position.
7. Check Dynamic Range of Vertical Display
Modes
a. Requirement— The dynamic range of the screen for the
three display modes is as follows-.
LIN > 26 dB
LOG > 40 dB
SQ LAW > 13 dB
b. Apply a 200 M H z signal (below — 40 dBm) from a
VHF Signal Generator that has a calibrated variable out­
put attenuator, to the RF INPUT connector.
c. Adjust the G A IN 'co ntrol and the variable attenuator
of the Signal Generator for a display amplitude of 6 cm.
(Full screen.)
d. Increase the output attenuation of the VHF Signal
Generator until the signal is just visible (about 0.5 mm) on
the display. Note the difference in the attenuator read­
ings between the full screen display and the 0.5 mm am­
plitude reading. This is the dynamic range.
e. Check the dynamic range of each VERTICAL DISPLAY
switch position. Must equal or exceed the ranges listed in
step a.
Fig. 5-4. Operation of the video filter.
f. Return the VERTICAL DISPLAY switch to the LIN posi­
tion.
6. Check Internal Reference Frequency
a. Requirement— Frequency is 1 M Hz ± 0 .1 % .
NOTE
This procedure checks the oscillator o p e ratio n .
If accuracy is to be verified a frequency counter
must be used.
b. Apply 10 ns and 1 /.is markers from the Time-Mark
Generator to the RF INPUT connector through a 20<tB at­
tenuator.
8. Check Accuracy of IF ATTEN dB Selectors
- a. Requirement— Accuracy of the IF ATTEN selectors is
within ± 0 .1 dB/dB of their indicated positions.
b. Apply a 200 M Hz signal from the signal generator
that is 10 dB below 1 mV, through a 2 X Attenuator (6 dB), a
Tens and Units Step Attenuator and a 1 0 X Attenuator (20 dB)
to the Type 1L30 RF INPUT connector. (Fig. 5-5.)
c. Set the Tens Attenuator for 20 dB attenuation and the*
Units Attenuator for 12 dB attenuation.
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