RF Central RFX-RMR, Руководство оператора

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RFX-RMR Issue 1.0 page 18 of
41
7.2 “3 in 1” Multi Down-converter
This board is mounted onto the motherboard as shown in the picture in section 4
The first part of the “3 in 1” multi down-converter accepts 630MHz at its input and converts this to
70MHz. The second part amplifies the 70MHz, applies AGC (automatic gain control), and passes this
signal to the final part which down-converts the signal to 4.57MHz.
A balanced form of the 4.57MHz IF is then passed to the COFDM demodulator board as detailed in
section 7.3
The module contains a 20MHz reference oscillator to lock the two mixer local oscillators.
There are no user serviceable parts on this module. Please contact RF Central Service Department
for maintenance of this unit
RMR RX
3 in 1 Multi down-converter Down-converter
780MHz
PLL/LO
Mixer BP filter
4.57MHz balanced
baseband to
demodulator
65.43MHz
PLL/LO
REF
OSC.
AGC
detector
70MHz
70MHz
BP filter
BP filter
630MHz from
1
st
downconverter
To analog RX
and IF monitor