Oscillator; Frequency Conversion; Frequency Of Local Oscillator - Furuno FS-1503 Service Manual

2.3 Oscillator

Taking J3E as an example, the outline of the frequency conversion is shown in Figure 2-6
and the relation between the transmitting and receiving frequencies and local frequencies
is shown in Table 2-6.
The frequency conversion circuit and the local oscillator circuit are included in TX/RX
board.
Outline of frequency conversion on J3E
T/RX
(Fo + 1.5 kHz)
Mode 1st Local oscillator (1Lo)
USB F + 54.455 MHz + 1.5 kHz
LSB F + 54.455 MHz - 1.5 kHz
TX
H3E
RX
F + 54.455 MHz ± 0 kHz
TLX
F + 54.455 MHz ± 0 kHz
FAX
54.455 MHz
1Lo
(F + 54.455 MHz + 1.5 kHz)
DDS
Ref. OSC
36MHz 1/2
Figure 2-6 Frequency Conversion
Table 2-5 Frequency of Local oscillator
F + 54.455 MHz + 1.5 kHz
F + 54.455 MHz ± 0 kHz
455 kHz
2Lo 3Lo
(54 MHz) (456.5 kHz)
Ref.
PLL 1
1/100
PLL 3
2nd Local oscillator
(2Lo)
54 MHz
54 MHz
54 MHz
54 MHz
54 MHz
54 MHz
2-13
AF
(1.5 kHz)
1 Lo
2 Lo
3 Lo
3rd Local oscillator
(3Lo)
456.5 kHz
453.5 kHz
TX 456.5 kHz
RX 455 kHz
456.7 kHz
456.7 kHz