Receiver If Circuit, Rx Part Of Crfrt; Last If Filter - Nokia 9000i Service Manual

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Technical Documentation

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.
Parameter
Supply voltage
Current consumption
Input frequency range
Local frequency range of
mixer
2nd IF range
Voltage gain (max. gain) of
AGC amplifier
Noise figure
AGC gain control slope
Mixer output 1dB compres-
sion point
Max output level after last IF
buffer

Last IF filter

The last IF is a ceramic filter, which makes the part of the channel
selectivity of the receiver.
Amendment 1 04/97
Table 9. CRFRT RX part Specifications
Minimum Typical /
Nominal
4.27 4.5
32.0
41 (–1 dB)
170
2
47
40 84
1.0
1.6
RAE/RAK–1N
Maximum Unit / Notes
4.73 V
44.0 mA
87 (–3 dB) MHz
400 MHz
17 MHz
dB
16 Max gain
100 dB/V
Vpp
Vpp
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RF