THOMSON VP2750 Technical Manual page 117

CONVERTER 1 AND OUTPUT STAGE
The 5.06-MHz signal is sent to the second input of Converter 1. This converter receives the
626,953-kHz incident signal at its other input, and outputs two frequencies:
The sum of two frequencies:
5.06 MHz + (626,953 kHz +800/-600)
and the difference between two frequencies:
5.06 MHz - (626,953 kHz +800/-600)
The difference component is selected by a low pass filter and is available at Outputs 48 and 50
of IV001.
4.43 MHz + 0.6/-0.8
Integrated Circuit IV100 corrects PAL chroma crosstalk. This chroma is delayed by two lines
and added to the direct channel.
The PAL chroma signal is available after filtering on IV001 Output 46.
ME SECAM PLAYBACK
ME SECAM playback is performed in a similar way to PAL playback. Note, however, that the
phase shifter and the phase detector and put out of operation in this case.
The signal goes through IV100 without any correction.
4.43 MHz NTSC PLAYBACK
Playback is performed in a similar way to PAL.
Note that the operating frequency of the VCO is 320 Fh. To correct crosstalk, circuit IV100
delays the signal by one line.
The NAP stage corrects bursts during NTSC playback, in Pause Mode, and in LP PAL slow
mode.
Technical documentation intended for professional maintenance personnel only.
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