Table of Contents
Advertisement
4-7. AVR circuit
The power supply voltage supplied from the Power unit
(X45-387 C/4) is distributed from the Receiver unit (X55-312)
CN44 to IC807 (9V), IC808 (5V), IC809 (8V).
The output of IC807 is supplied to the 1st and 2nd VCO
circuits.
The output of IC808 is supplied to the LNA, down con-
verter, and the 1st local amplifi ers.
The output of IC809 is distributed to IC801 (5V), IC802
(5V), IC803 (5V) and IC804 (5V).
CN44
External DC
power supply
4-8. Other circuits
Other circuits include the EEPROM (IC813), the tem-
perature sensor IC (IC806), the DAC (IC805) and the ADC
(IC811).
IC813 saves various adjustment values of the Receiver
unit.
IC806 is built-in for detecting changes in temperature.
The IC805 pin 1 voltage adjusts the RSSI voltage from
the analog FM system IC, IC207 pin 12. The IC805 pin 2
voltage adjusts the 1st VCO's control voltage. The IC805 pin
3 voltage adjusts the RF AGC operation point.
IC811 monitors the 1st-VCO control voltage (pin 16),
the LNA current detection value (pin 15), the temperature
detected by the temperature sensor IC (IC806 pin 14), the
RSSI voltage detected by the analog IF system IC (IC207
pin 12), the squelch voltage detected by the IF system IC
(IC207 pin 9) and the control voltage of the 2nd-VCO (pin
10). IC811 sends each input port state(s) in serial data ports
pin 1, 2, 3 and 18 from CN42 to the Control unit (X53-413).
The signal is processed by the MPU.
CIRCUIT DESCRIPTION
IC807
IC808
IC809
IC804
IC802
IC803
IC801
Fig. 19 AVR circuit
The output of IC801 is supplied to the PLL IC's charge-
pump, buffer amplifi ers, IC4 (3.3V), IC605 (3.3V) and IC606
(3.3V). The output of IC606 is supplied to PLL serial data
driver IC602 and IC604. The output of IC4 and IC605 are
supplied to the PLL ICs logic part.
The output of IC802 is supplied to the DAC, ADC and
RSSI buffer OP amp ICs.
The output of IC803 is supplied to 1st IF amplifi ers and
analog FM system IC.
The output of IC804 is supplied to the digital mode IF
system IC.
VCOs, Active LPF
LNA, 1st mixer, Lo AMP, Lo doubler, RF AGC
5V digital mode IF system
IC503
3.3V 2nd IF AMP
5V common
5V analog mode IF system
5V PLL
IC605
3.3V PLL IC
IC606
3.3V PLL IC
IC4
3.3V PLL IC
IC812
1
A/2
IC805
1st
2
VCO_A
1st
3
VCO_B
IC601
10
2nd CV
IC207
11
ASQL
IC814
12
RSSI
IC811
IC806
14
TEMP.
IC201
15
LNA
IC1
16
1st CV
Fig. 20 Other circuits
NXR-901
11
6
9
7
8
8
22
18
IC813
EEPROM
5
32
30
6
CN42
17
Advertisement
Table of Contents
