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LANSDALE Semiconductor, Inc.

ML145106

Figure 5. VHF Aircraft 720 Channel Two Crystal Frequency Synthesizer

5.12 MHz

VDD

GND

RECEIVE

11.31 MHz

(SELECT FREQUENCY TO

GIVE DESIRED R/T OFFSET)

TRANSMIT

10.24 MHz

TRANSMIT

11.0500 MHz

11.0525 MHz

RECEIVE

12.1200 MHz

12.1225 MHz

0

1

0

0

0

1

0

1

810 kHz – 812.5 kHz

N = 324 – 325

LOCK DETECT

AMP

OSC

MIXER

#2

VDD

GND

OFFSET LOOP

PROGRAMMING

÷ N 29 – 1

2.5 kHz

MC145106

REF OSC

AND

÷ 2

÷ 10

MIXER

#1

LOCK DETECT

TRANSMIT

118.000 – 135.975 MHz

(25 kHz STEPS)

RECEIVE

128.700 – 146.675 MHz

10.24 MHz

VCO AND

BUFFER

LOOP

FILTER

VHF LOOP

PROGRAMMING

750 kHz – 2545 kHz

N = 150 – 509

÷ N 29 – 1

5.0 kHz

MC145106

PHASE

DETECTOR

29, 210

DIVIDER

÷ 2

REF

OSC

LOOP

FILTER

VCO AND

BUFFER

PHASE

DETECTOR

29, 210

DIVIDER

Legacy Applications Information