Philips DVDR985 Technical Training Manual page 94

There are also two SVideo input connection pos-
sibilities: Front and Rear SVideo In, which are
connected to the input selector IC 7400 and
7401. Refer to Figure 49. One is used for Y, the
other is used for Chroma switching. The outputs
of 7400 and 7401 are connected to 7507, where
the signals are routed as the Y/C selected input.
Wideband Signal Selection/WSS on Y/C-Plug
Both 16 by 9 and 4 by 3 Y/C signals can be pro-
vided to the Y/C connector. The Chroma signal
is sent to the Microcomputer, 7803. Pin 14 is
used when using the Rear Y/C input, WSR1; and
Pin 15 is used when using the Front Y/C connec-
tor, WSF1. Pin 10 of 7803 indicates which dis-
play ratio the Microcomputer is detecting. Pin 10
is Low for 4 by 3, and High for 16 by 9.
Figure 49 - Rear Input Selection
The Audio I/O switching is also controlled by
7507 via the I 2 C Bus. Analog Audio coming from
Rear External Inputs 1,2 and External 3 are
capacitively coupled to IC7507, Pins 35, 37, 53,
and 56. Digital Board input and Tuner Audio is
routed via 7600 to 7507, Pins 39 and 41. 7507
selects the audio source.
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