After Sales
Technical Documentation
RAE/RAK–1N
RF
Page 3– 17
Amendment 1 04/97
Receiver IF circuit, RX part of CRFRT
The receiver part of CRFRT consists of an AGC amplifier of 57 dB gain, a
mixer and a buffer amplifier for the last IF. The mixer of the circuit down
converts the received signal to the last IF frequency. After external filtering
the signal is amplified and fed to baseband circuitry. The supply current
can be switched OFF by an internal switch, when the RX is OFF.
Table 9. CRFRT RX part Specifications
Parameter Minimum Typical /
Nominal
Maximum Unit / Notes
Supply voltage 4.27 4.5 4.73 V
Current consumption 32.0 44.0 mA
Input frequency range 41 (–1 dB) 87 (–3 dB) MHz
Local frequency range of
mixer
170 400 MHz
2nd IF range 2 17 MHz
Voltage gain (max. gain) of
AGC amplifier
47 dB
Noise figure 16 Max gain
AGC gain control slope 40 84 100 dB/V
Mixer output 1dB compres-
sion point
1.0 Vpp
Max output level after last IF
buffer
1.6 Vpp
Last IF filter
The last IF is a ceramic filter, which makes the part of the channel
selectivity of the receiver.
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