QUANZHOU WOUXUN ELECTRONICS CO., LTD Model: KG-689
Version: KG-689-0801-V1 Page 9 of 35
5C
T337
T355
T350
T375
T370
D352
D353
D346
D345
D348
MOD
TX/RX
PLL DATA
10
11
12
13
3
5
20
5C
66
65
64
63
CPU
U811
5C
CR311
19.2MHz
PLL
U311
图
6
Circuit Description
5. PLL Circuit
(1) PLL
19.25MHz reference oscillator output through PLL IC(U311) reference frequency then bring 5KHz and 6.5
KHz reference frequency.
VCO output signal blew up by T337, then bring compare frequency by U311 dispart frequency. Use different
dispart frequency ratio by CR311, and get different inspect posture consult frequency. According referenced
frequency and comparable frequency value, then bring 5, 6.25, 10, 12.5 and 25KHz for step frequency
value of PLL synthesizer. According referenced frequency and comparable frequency discrepancy value,
the output correspond pulse voltage from the fifth feet of U311, change it to direct current signal direct
current signal by filter after through Charge Pump, then bring lock voltage.
(2) VCO
Goal frequency is make up of FETT355 and T350 directly produced by Rapids oscillator. Lock controllable
voltage and then modify oscillator frequency by D353, D352, D346 and D345.
(3) Lose lock detection circuit
When PLL is on lose lock, one pulse will be plastic by R312 D312 C312 and R313, then add to LD side of
PLL (tenth LD side), and the voltage of LD side will be rose, CPU will control transmitting and receiving by
detecting the voltage of LD side.
(4) Digital control circuit
Conformation of Keyboard circuit: Directly input the signal come From the keyboard to CPU (U811).
Chart 6
5C
T337
T355
T350
T375
T370
D352
D353
D346
D345
D348
MOD
TX/RX
PLL DATA
10
11
12
13
3
5
20
5C
66
65
64
63
CPU
U811
5C
CR311
19.2MHz
PLL
U311
图
6
Chart 6
wouxun
wouxun
wouxun
wouxun
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