Tektronix 1L30, Instruction Manual

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Operating Instructions— Type 1L30
Fig. 2-18. Pulse modulated displays.
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reading). The frequency of an applied signal is measured
as follows:
1. Check the calibration of the IF CENTER FREQ CAL a d ­
justment as described previously.
2. Set both the IF CENTER FREQ controls and the FINE RF
CENTER FREQ control to their midrange (000) position.
3. Set the DISPERSION RANGE switch to k H z /C M and
the DISPERSION selector to 500 kHz/cm position .
4. Tune the RF CENTER FREQ control so the signal to be
measured is centered within the graticule area.
5. Read the frequency indicated on the RF CENTER FREQ
dial. This reading is accurate to within r t (2 M H z + 1% of
the dial reading). For example: A dial reading of 5000 M Hz
indicates the signal is 5000 M Hz ± (2 M H z + 5 0 M Hz) or,
between 4948 M H z and 5052 MHz.
Accurate frequency measurements can be performed by
applying a calibrated or crystal-controlled frequency to the
RF INPUT and calibrating the dial near the frequency range
of the input signal; then tune the input signal to the same
screen position and note the dial reading plus or minus the
measured dial error.
Frequency Difference Measurements
Frequency separation measurements to 100 M H z c a n .b e
performed as follows:
1. Adjust the DISPERSION RANGE switch and the DIS­
PERSION selector so the signals to be measured are the
maximum number or graticule divisions apart on the display.
2. Set the Time/Cm selector and the RESOLUTION control
for optimum signal definition.
3. Measure the distance in centimeters between the two
signals (see Fig. 2-19).
4. Multiply the measured distance in step 3 by the Disper-
sion/Cm setting. This is the frequency separation or fre­
quency difference between the two signals.
Fig. 2-19. Frequency difference measurement between two signals.
DISPERSION RANGE setting = MHz/CM
DISPERSION setting — 2
Frequency difference — (7 cm) (2 MHz/CM) = 14 MHz
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