Circumference Circuits; Clock Pulse Generator; Remote Control Circuit; Shaping Circuit And Filter - Radio Shack TRS-80 Service Manual

4. CIRCUMFERENCE CIRCUITS
4-1. Clock Pulse Generator
32,768 Hz signal is generated by the crystal oscillator and is shaped by the inverters.
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o
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4-2. Remote Control Circuit
LSI
C1
Q1
Q2
-3V
When signal C1 is HIGH, transistors Q1 and Q2 turn on causing relay RY to be
switched on so that the REMOTE terminal becomes active.
4-3. Shaping Circuit and Filter
MIC
EAR
LSI
C2
C3
1+-----1-----,.AII!'----.--+-fl--I-~--r>tN-;;_---t.--..J
11
~
12
I--f---'
L..-
~
' - - -_ _
-L-_Y-_--L.
---->,------'~
-3V
CD
-18-