Tektronix 1L20, Instruction Manual

Page: 60 / 117

C alibration— Type 1L20
Fig. 6 -2 5 . Setup for checking VIDEO INPUT.
19. Check Frequency Response of VIDEO INPUT
Circuit
a. Connect the equipment as shown in Fig. 6-27.
b. Preset the controls o f the Spectrum Analyzer as follows:
POS Position the trace to the
center line of the graticule
G A IN Fully clockwise
VERTICAL DISPLAY VIDEO
c. A pply a 50 kHz signal from the audio generator to
the VIDEO INPUT connector of the Analyzer. Adjust the
Output control of the generator to obtain 4 centimeters of
deflection.
d. Monitor the signal amplitude with a DC coupled test
oscilloscope for constant amplitude, and decrease the output
frequency o f the generator.
e. The frequency at which the Analyzer display falls to
2.8 centimeters should be < 1 6 Hz.
f. A pply a 50 kHz signal from the Constant Amplitude
RF Generator to the VIDEO INPUT connector of the Analyzer.
Adjust the signal amplitude for 4 centimeters of deflection.
g. Increase the signal frequency until the amplitude of
the Analyzer display falls to 2.8 centimeters. A t this point
the output frequency should be > 1 0 MHz.
NOTES
6-20