Kenwood TS-440S Serivce Manual page 19

TS-440S
CIRCUIT DESCRIPTIO N
1 . Encode r
The TS-440S uses an optical encorder . Two different cloc k
signals from the encoder are 90°, out of phase with eac h
other . This phase difference is not adjustable but depend s
on the precision of the module . The two clock signals are
converted into clock pulses (250 pulses/rotation x 4) and U/ D
signals indicating the direction of rotation by the 4011 an d
4030 and fed into the 7800 . Figure 1 5 is a timing chart fo r
clock pulse and the U/D signal transmitted to the 7800 .
,uPD7800G
Fig . 14 Encoder circui t
4I I
B 6
8 8
8 4
8 3
81 1
C 4
A 4
CI O
A1 0
C 2
012
84 BI I
BIO 8 3
BIO 81 1
B4 - B 3
COUNT PULS E
BIG
I —
U/D SIGNA L
Fig . 15 Encoder waveform timing chart
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