Video Signal Path Explanation; Ntsc \ 480I Video Signal Path - Panasonic TH-42PX20U Service Update Information

Video Signal Path Explanation

Figure 4

NTSC \ 480i Video Signal Path

The TH-42PA20U/P incorporates two NTSC tuners, allowing the simultaneous
viewing of two signals. It is also equipped with three NTSC Video inputs and
three NTSC S-Video inputs. Tuner-1 produces audio and video signals. Tuner-2
produces video only, as it is the video source intended for use in the "Picture in
Picture" mode. Video signals produced by the main tuner (tuner-1) and sub tuner
(tuner-2) are applied to the H-Board via pin 1 of the connector T11/H11 and pin 1
of the connector T21/H21. The signal applied to the AV3 video input, located at
the bottom of the front panel, enters the G-Board and passes through to the DG-
Board without alteration. It is then applied to the H Board.
IC4301 on the H-Board selects the main video source and sub video source from
the NTSC inputs. The main Video or Luminance and chrominance signals are
output via pins 56 and 58. The sub video signal is output via pins 39 and 37. Both
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