Radio Shack TRS-80 Service Manual page 20

Filter waveforms
~
approx. ' " "--
~
1.2kHz
~
~
approx. 2.4 kHz
-3V
@
-3V
®
A "
~
A f \ / \ { \ ( \ f \ ! \ /
J
\J\7~
V\TVV V
\T
-3V
Data output C2 from the LSI is integrated (waveform @) and shaped into an AC
waveform (waveform
® )
by capacitor cl and resistor rl.
®
@
~
A /\ /\J\ .
"V
VVVV
Input signal from tape recorder
CD
is integrated by capacitor c2 and resistors r2
and r3 (waveform
@).
The waveform
®
is cramped between -3V and OV by diodes dl and d2.
- 19-
OV
OV
-3V