Tektronix 1L30, Instruction Manual

Page: 56 / 129

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Performance Check— Type 1L3Q
k. Return the DISPERSION-COUPLED RESOLUTION con­
trols to 500 kHz/ cm position.
13. Check Display Flatness
a. Requirement— Display flatness with the IF CENTER
FREQ controls centered, is ± 1 . 5 dB within + and — 50 M Hz
of the RF center frequency.
b. Set the front panel controls as follows:
DISPERSION RANGE
DISPERSION
VERTICAL DISPLAY
IF CENTER FREQ
IF ATTEN dB
Time/Cm
M H z /C M
5 M H z/cm
LIN
Centered (000)
20 dB
5 ms
c. Apply the required signal frequency listed in Table
5-4, from the Signal Generator through a 20 dB attenuator
(Part No. 011-0086-00) to the RF INPUT connector.
d. Tune the RF CENTER FREQ control to the frequency
listed in Table 5-4, then adjust the Signal Generator output
control until a signal is visible on the CRT.
"I
e. .Adjust the MIXER PEAKING control for optimum sig­
nal amplitude then adjust the Type 1L30.G A IN control and
the generator output for a signal amplitude of 5 cm. Re­
peat this procedure each time the generator frequency is
changed.
f. Check the display flatness by tuning the signal across
the screen (from left to right edge) with the RF CENTER FREQ
control. Signal amplitude should not change more than ± 1 .5
dB from the average amplitude, or 3 dB total.
NOTE
There is a possibility th at the reference 5 cm signal
am plitude adjustment was set a t the maximum or
minimum response point of the dispersion w indow .
Use the averag e signal am plitude over the disper­
sion w in d ow as the reference.
TABLE 5 -4
RF Center Frequency
A p p lied or Signal
G e n e ra to r Frequency
1450 M Hz - 1550 M Hz (Scale 1)
1500 MHz
1950 MHz - 2050 MHz (Scale 1) 2000 MHz
2450 MHz - 2550 MHz (Scale 2) 2500 MHz
2950 MHz - 3050 MHz (Scale 2) 3000 MHz
3450 MHz - 3550 MHz (Scale 2) ■ 3500 MHz
4200 MHz - 4300 MHz (Scale 3) 4500 MHz
4750 M Hz - 4850 M Hz (Scale 4)
4800 MHz
5750 M Hz - 5850 MHz (Scale 4)
5800 MHz
6750 M Hz. - 685QMHz (Scale 5) 6800 MHz
14. Check RF Center Frequency C a lib ra tio n ,
System Sensitivity and Phase Lock •
Operation
a. Requirement— D ial accuracy w ithin ± (2 M Hz - f i % of
the dial reading); sensitivity within .that specified in Table
5-5; phase lock operates through all frequency ranges.
b. Apply a frequency and amplitude c alibra ted signal,
between — 60 dBm and — 30 dBm, to the RF
IN PUT
connector.
NOTE
If an extern a l a tte n u a to r is used, it must have flat-
high frequ en cy characteristics: Use Tektronix
2C dB
RF A tte n u a to r Part N o . 0 1 1 - 0 0 8 6 - 0 0 or 4 0 dB
A tte n u a to r Part N o . 0 1 1 - 0 0 8 7 - 0 0 .
c. Set the DISPERSION control to 500kH z/cm and the
RESOLUTION control for a resolution bandwidth of 100 kHz
(fully clockwise).
d. Adjust the G A IN control for an average noise am pli­
tude of one division. Center the IF CENTER FREQ and FINE
RF CENTER FREQ controls. Adjust the MIXER PEAKING for
maximum signal amplitude.
e. Tune the signal on the screen with the RF CENTER FREQ
control. Reduce the signal amplitude with the Signal G ener­
ator output attenuator control for an on-screen display; then
re-adjust the MIXER PEAKING control and sweep rale for
optimum signal amplitude. (Sweep rate approximately 10
ms/cm or slower.)
f. Calibrate the Signal Generator output, then adjust the
variable output attenuator control on the Signal G enerator
until the signal amplitude is two divisions (twice the noise
amplitude). See Fig. 5-7.
Fig. 5-7. Signal to noise ratio for measuring sensitivity.
g. Check the total signal attenuation (in dB) below 0
dBm as indicated on the Signal G enerator attenuator dial.
This is the sensitivity c f the analyzer for the RF center fre ­
quency indicated. Check the analyzer sensitivity tm ough the
band as listed in Table 5-5 u n d e r' 100 kHz resc±!;vn. Sens­
itivity can also be checked for 1 kHz resolution, however., a
very stable signal source is required at the higher frequencies.
©
5 -8