ML145106-6P データシートの表示（PDF） - LANSDALE Semiconductor Inc.
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ML145106-6P Datasheet PDF : 8 Pages
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ML145106
LANSDALE Semiconductor, Inc.
Legacy Applications Information
PLL SYNTHESIZER APPLICATIONS
The ML145106 is well suited for applications in CB radios
because of the channelized frequency requirements. A typical
40 channel CB transceiver synthesizer, using a single crystal
reference, is shown in Figure 3 for receiver IF values of 10.695
MHz and 455 kHz.
In addition to applications in CB radios, the MC145106 can
be used as a synthesizer for several other systems. Various fre-
quency spectrums can be achieved through the use of proper
offset, prescaling, and loop programming techniques. In gener-
al, 300 – 400 channels can be synthesized using a single loop,
with many additional channels available when multiple loop
approaches are employed. Figures 4 and 5 are examples of
some possibilities.
In the aircraft synthesizer of Figure 5, the VHF loop (top)
will provide a 50 kHz, 360 channel system with 10.7 MHz R/T
offset when only the 11.0500 MHz (transmit) and 12.1200
MHz (receive) frequencies are provided to mixer #1. When
these signals are provided with crystal oscillators, the result is
a three crystal 360 channel, 50 kHz step synthesizer. When
using the offset loop (bottom) in Figure 5 to provide the indi-
cated injection frequencies for mixer #1 (two for transmit and
two for receive) 360 additional channels are possible. This
results in a 720–channel, 25 kHz step synthesizer which
requires only two crystals and provides R/T offset capability.
The receive offset value is determined by the 11.31 MHz crys-
tal frequency and is 10.7 MHz for the example.
The VHF marine synthesizer in Figure 4 depicts a single
loop approach for FM transceivers. The VCO operates on fre-
quency during transmit and is offset downward during receive.
The offset corresponds to the receive IF (10.7 MHz) for chan-
nels having identical receive/transmit frequencies (simplex),
and is (10.7 – 4.6 = 6.1) MHz for duplex channels. Carrier
modulation is introduced in the loop during transmit.
10.24
MHz
29/210
OSC
2
ML145106 5.0 kHz
PROGRAMMABLE
DIVIDER
PHASE
DETECTOR
LD
LOOP
FILTER
26.965 – 27.405 MHz
VCO
BUFFER
(TRANSMIT)
26.510 – 26.950 MHz
(RECEIVE)
SWITCH WAFERS
VDD GND
R/T
BUFFER
MIXER
1.365 – 1.805 MHz (TRANSMIT)
10.24 MHz
16.270 – 16.710 MHz
0.91 – 1.35 MHz (RECEIVE)
TO RECEIVER
RECEIVER 1ST
2ND MIXER
LOCAL OSC SIGNAL
X5
25.6 MHz
MIXER
Figure 3. Single Crystal CB Synthesizer Featuring On–Frequency VCO During Transmit
Page 5 of 8
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