Midland SYN-TECH 70-050 - Page 14

THEORY OF OPERATION
70-050/055
Crystal XI generates a stable reference frequency for IC3
generation and detection. IC 4 functions as an audio highpass filte
remove CTCSS tones from the speaker audio. Encode tone output is
IC3 pin 16 with tone modulation level adjustable by RV1.
tone
r to
from
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