Four-Head High-Speed Switching Circuit For Special Playback; Overview; Block Diagram - Renesas Hitachi H8S/2194 Series Hardware Manual

28.5

Four-head High-speed Switching Circuit for Special Playback

28.5.1

Overview

This four-head high-speed switching circuit generates a color rotary signal (C.Rotary) and head-
amplifier switching signal (H.Amp SW) for use in four-head special playback.
A pre-amplifier output comparison result signal is input from the COMP pin. The signal output
at the C.Rotary pin is a Chroma signal processing control signal. The signal output at the
H.Amp SW pin is a pre-amplifier output select signal. To reduce the width of noise bars, the
C.Rotary and H.Amp SW signals are synchronized to the horizontal sync signal (OSCH). OSCH
is made by adding supplemented H, which has been separated from the Csync signal in the sync
signal detector circuit. For more details of OSCH, see section 28.15, Sync Signal Detector.
If the C.Rotary, H.Amp SW or COMP pin does not require this circuit to configure a VCR
system, it can be used as an I/O port.
28.5.2

Block Diagram

Figure 28.26 shows the block diagram of this circuit.
COMP
Narrow.FF
Video.FF
Figure 28.26 Four-Head High-Speed Switching Circuit for Special Playback
Internal bus
W
· CHCR
SIG3 to 0
Synchronization
control
V/N
· CHCR
W
Internal bus
W W
· CHCR
CRH HAH
Decoding circuit
HSWPOL
· CHCR
W
Rev. 2.0, 11/00, page 677 of 1037
OSCH
(Synchronization)
C.Rotary
H.Amp SW
RTP0