Specifications

124 Chapter 14
Demodulating and Viewing Television Signals (ESA-E Series Option B7B)
Demodulating and Viewing Television Signals
Demodulatin
g
and Viewin
g
Television Signals (ESA-E Series
Option B7B)
A time domain display of the demodulated TV waveform will now be
visible. The signals used for Figure 14-1 were produced by a Phillips
PM 5518-TX Color TV Pattern Generator.
Figure 14-1 Demodulated RF Waveform
LEFT: NTSC; PAL is Similar
RIGHT: SECAM
If
Trig, TV is the active function, the line number used to trigger the
analyzer sweep can be changed to examine the different parts of the
video waveform. The line numbering scheme varies with TV standard,
but TV test patterns will often be inserted in or near line 17.
Step 14. Set a long sweep time of 100 seconds to minimize disruption of the
analog signal path during the instrument retrace to optimize picture
quality:
Press
Sweep, Sweep Time, 100, s.
Step 15. To obtain the best color picture quality with NTSC and PAL signals, set
the center frequency 1.75 MHz above the video carrier frequency:
Press
FREQUENCY Channel, CF Step, 1.75, MHz, Center Freq, ⇑.
Setting the center frequency above the video carrier frequency centers
the analyzer’s tuned frequency between the video carrier and the color
subcarrier.
Step 16. Turn on the spectrum analyzer display into a TV monitor:
Press
Trig, TV Trig Setup, TV Monitor.