MC145106DW MOTOROLA [Motorola, Inc], MC145106DW Datasheet - Page 5

• Manufacturer Part Number: MC145106DW
• Description: PLL FREQUENCY SYNTHESIZER CMOS
• Manufacturer: MOTOROLA [Motorola, Inc]

because of the channelized frequency requirements. A typi-
cal 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.
be used as a synthesizer for several other systems. Various
frequency spectrums can be achieved through the use of
proper offset, prescaling, and loop programming techniques.
In general, 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.
will provide a 50 kHz, 360 channel system with 10.7 MHz
R/T offset when only the 11.0500 MHz (transmit) and
MC145106
5
The MC145106 is well suited for applications in CB radios
In addition to applications in CB radios, the MC145106 can
In the aircraft synthesizer of Figure 5, the VHF loop (top)
10.24
MHz
PLL SYNTHESIZER APPLICATIONS
X 5
Figure 3. Single Crystal CB Synthesizer Featuring On–Frequency VCO During Transmit
R/T
25.6 MHz
OSC
PROGRAMMABLE
SWITCH WAFERS
MC145106
DIVIDER
MIXER
1.365 – 1.805 MHz (TRANSMIT)
2
0.91 – 1.35 MHz (RECEIVE)
5.0 kHz
2 9 /2 10
V DD
DETECTOR
PHASE
BUFFER
GND
TO RECEIVER
2ND MIXER
FILTER
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
indicated 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
crystal frequency and is 10.7 MHz for the example.
loop approach for FM transceivers. The VCO operates on fre-
quency during transmit and is offset downward during re-
ceive. The offset corresponds to the receive IF (10.7 MHz) for
channels having identical receive/transmit frequencies (sim-
plex), and is (10.7 – 4.6 = 6.1) MHz for duplex channels. Car-
rier modulation is introduced in the loop during transmit.
LOOP
LD
The VHF marine synthesizer in Figure 4 depicts a single
10.24 MHz
LOCAL OSC SIGNAL
RECEIVER 1ST
VCO
MIXER
16.270 – 16.710 MHz
BUFFER
26.965 – 27.405 MHz
26.510 – 26.950 MHz
(TRANSMIT)
MOTOROLA
(RECEIVE)