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Performance Verification
4–34
1780R-Series Service Manual
b. Set the generator Luminance button to On (pressed in).
c. Set the 1780R-Series controls as follows: INPUT to CH A, WFM
HORIZONTAL to ONE–LINE, MAGNIFIER to 1.0 ms/DIV, and
WAVEFORM GAIN to X5.
d. Use the VERT POS control to move the signal baseline between the
–40 IRE and +100 IRE graticule lines for NTSC (0 V and 1.0 V for
PAL).
e. Check that the bottom of the modulated pulse does not change more than
5 IRE for NTSC (36 mV for NTSC or PAL) as measured using the
graticule. Equivalent to 7 mV when WAVEFORM GAIN – X5 is set to
Off.
f. Set the MAGNIFIER and WAVEFORM GAIN–X5 to Off.
g. Leave the Pulse & Bar signal connected to the CH A INPUT connector.
24. Check DC Restorer Shift Versus Burst
Supplemental: Equal to or less than 1 IRE (NTSC) or 7 mV (PAL).
a. Check that a Pulse & Bar signal is applied to the 1780R-Series CH A
INPUT connector.
b. Set the 1780R-Series WFM HORIZONTAL buttons to TWO–FIELD.
Check that the CONFIGURE button is On and DC RESTORER–FAST
is selected on the Configure menu.
c. Use the VERT POS control to move the signal blanking level to the
Waveform CRT graticule baseline (0 IRE for NTSC; 0.3 V for PAL).
d. Check by setting the generator Burst switch to Off and then to On, that
the signal blanking level moves less than 1 IRE for NTSC (7 mV for
PAL).
e. Select CLAMP–ST on PAGE 1 of the Configure menu.
f. Verify that the sync tip goes to the graticule baseline. The graticule
baseline is 0 IRE for NTSC; 0.3 V for PAL.
g. Check that by setting the generator Burst switch to Off and On, the sync
tip moves less than 1 IRE for NTSC (7 mV for PAL).
h. Select CLAMP–BP on the Configure menu. Set the generator Burst
switch to On.
i. Leave the Pulse & Bar signal connected to the instrument.