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ME1000 RF Circuit Design
Quick Start Guide - 20/23
Appendix B: ME1000 Receiver Unit
The Receiver Unit (RX) contains the basic blocks of a typical RF front-end system as follows:
•
RF Frequency Synthesizer.
•
Bandpass Filters.
•
Downconverter.
•
Low-Noise Amplifier.
•
Intermediate Frequency (IF) Amplifier.
The block diagram of the RX is shown below. The antenna on the RX accepts a modulated 868 MHz
RF signal with a maximum bandwidth of 1 MHz. This is amplified by the Low-Noise Amplifier and
subsequently downconverted to a 50 MHz IF signal by the Downconverter. The variable gain IF
Amplifier provides further amplification of the IF signal to a maximum of 3 mW (into a 50
Ω
load). The
RF and IF Bandpass Filters suppress unwanted frequency components. The Low-Noise Amplifier,
Downconverter, Frequency Synthesizer, and IF Amplifier, being active circuits, are controlled by the
Control Unit. The Control Unit receives commands from the personal computer (PC) via the universal
serial bus (USB) port. Applications running on the PC intercept the user’s instructions and send
appropriate commands to the Control Unit of the RX. The Control Unit in turn provides the necessary
power and control signals to the active circuits.
Antenna
Low-Noise
Amplifier
RF
Bandpass
Filter
Synthesizer
Control Unit
Downconverter
IF Bandpass
Filter
IF
Amplifier
Receiver Unit
mixer
in
mixer
out
mixer LO
in
synthesizer
out
filter
out
filter
in
amp
out
amp
in
filter
out
filter
in
USB
port
amp
out
amp
in
