Tektronix 1L40, Инструкция по эксплуатации

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Performance C heek/Calibration— Type 1L40
Fig. 5-6. D isplay pattern when resolution is correctly adjusted.
f. Change the RESOLUTION control to the 1 kHz position
(fully counterclockwise) and the DISPERSION to 1 kHz/cm
keeping the 200 MHz signal centered on screen with the IF
CENTER FREQ controls.
g. CHECK— the resolution bandwidth at the ~ 6 d B ampli­
tude point. Bandwidth must not exceed 1 kHz. See Fig. 5-6B.
h. Return the RESOLUTION selector to the coupled posi­
tion and set the DISPERSION-COUPLED RESOLUTION con­
trols to 500 kHz/cm position.
3(B). Adjust IF Amplifier Response and O
the Analyzer Resolution Bandwidth
For Calibration only, omit for Performance Check and pro­
ceed to step 4(A).
a. The equipment setup is shown in Fig. 5-5.
b. Apply a 200 MHz signal (2nd harmonic of 10 ns) from
the Time-Mark Generator (Type 184) through a 20 B attenu­
ator, 50 Q termination and proper adapter to the RF INPUT
connector. Switch in 20 dB of IF Attenuator on the Type 1L40.
NOTE
This 200 MHz signal may be a p p lie d through a
P6041 probe ca b le a d a p te r to the Sealectro con­
nector, J100, on the w id e bandpass filte r assembly.
Fig. 5 -7 . Location o f the IF a m p lifie r peaking adjustments.
c. Turn the G A IN control fully clockwise and switch in the
required IF Attenuation to reduce the signal amplitude to
approximately 4 cm.
d. ADJUST— LI44 (wide band amplifier) T464, T454, C435
and C425 (narrow band amplifier), see Fig. 5-7, in the order
listed for maximum signal amplitude.
e. ADJUST— L444, see Fig. 5-7, for stable 70 MHz oscillator
operation. The stable point is midway between the two
oscillator drop out points when the core of L444 is turned in
and out through the operating range.
f. Remove the P6041 probe adapter cable, if connected,
and reconnect the coaxial cable to J100.
g. Set DISPERSION to 50 kHz/cm and the RESOLUTION
control fully clockwise. Adjust the IF CENTER FREQ controls
to center the display on graticule.
h. Connect the 10X probe from the test oscilloscope to
pin B of the honeycomb pin connector, see Fig. 5-7.
I. Adjust the Type 1L40 G A IN control for a display am pli­
tude of 6 cm on the indicator oscilloscope. Adjust the Trig­
ger Level and Slope controls to obtain a stable display on
the test oscilloscope. Adjust the test oscilloscope Volts/Cm
selector for a display amplitude of approximately 6 centi­
meters. See Fig. 5-8.
j. ADJUST— 100 kHz Resol Cal R543 so the display re­
sponse is just beginning to overcouple, (slight dip in the
center). Bandpass response on the analyzer oscilloscope
should decrease to approximately 60 kHz at the — 6 dB point
when the RESOLUTION selector is turned ccw one step from
the full cw position.
k. W ith the RESOLUTION control fully cw, adjust C504
and C508 (Fig. 5-9) for optimum display symmetry on the
test oscilloscope. See Fig. 5-8. Adjust C504 for the slope of
the response and C508 for symmetry. When correctly adjust­
ed, the test oscilloscope display w ill remain fairly symmetri­
cal through each position of the RESOLUTION control.
Remove the test oscilloscope probe. Return the RESOLU­
TION control to the fully clockwise position.
5 -9