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Performance Check and Calibration Procedures
1–22
TPG20 Service
Repeat parts d through f of this step for the following formats using the
Groups: FLAT FIELDS; WHITE 100% in each format.
FORMAT 625/50 COMPOSITE PAL/D2
FORMAT 625/50 COMPONENT D1/YPrPb
FORMAT 625/50 COMPONENT YPrPb
FORMAT 625/50 COMPOSITE SECAM
FORMAT 525/60 COMPOSITE NTSC D2 (use White 100 IRE)
FORMAT 525/60 COMPONENT D1/YPrPb
FORMAT 525/60 COMPONENT YPrPb
FORMAT 525/60 COMPONENT RGB
6. DAC Offset Calibration
a. Set TPG20:
FORMAT 625/50 COMPONENT RGB
Groups: PULSES; PULSE & BAR 2T 625 RGB
b. Connect TPG20 Analog Output A to both channels of the oscilloscope,
using the dual input connector. Set the oscilloscope to 0.1 Volts/Div,
invert one of the channels and sum them. Adjust variable gain on one
channel to null the signal.
c. Connect TPG20 Analog Ouput A to channel one of the oscillocope.
Connect TPG20 Analog Output B to channel two of the oscillocope.
Retain all previous settings, triggering the oscilloscope on channel two.
d. Press the TPG20 SYSTEM button to select – Set: DAC B Offset
e. Adjust – the TPG20 B Analog Output level, using the front panel knob
to obtain the best cancellation of the pulse and bar signal on the
oscillocope.
f. Press the TPG20 SELECT button to save this setting.
g. Substitute TPG20 Analog C Output at channel two of the oscillocope.
h. Press TPG20 SYSTEM button to select – Set: DAC C Offset
i. Adjust – the TPG20 C Analog Output level using the front panel knob
to obtain the best cancellation of the pulse and bar signal on the
oscillocope.