QUANZHOUBAOJIE ELECTRONICS CO.,LTD. Model:BJ-9900
Version:BJ-9900-0812-V1 Page 7 of 75
Sub-band
when there is not receivable carrier signal in sub-band , the output nosies for the IC1047
detector will be amplified while the band pass will be filtered by the IC1047''s noises
amplified part. The generated direct voltage will be transferred to of Main CPU IC1107
pin28 which will compare the squelch standard level with the settable squelch level in
the front panel which can setted through SQL key.
Transmitter signal channel
Audio signal
The audio signal which arrive at loud-speaker are transferred to the audio amplifier
U3001 of PANEL-SUB UNIT through the Mic Plug J3004.The amplified audio signal
via the front panel separated plug J3002 and J1005 transmit to TX-RX unit where the
audio signal is transferred to the audio processor IC IC1042 and related circuit.
430 MHz
signal
The audio signal which arrives at l IC1042 are transferred to variable resistance diode
through transistor exchanger Q1114 and Q1115.Where the frequency modulates
composed and emission voltage controlled oscillator which compose of UHF-VCO/B
Q1116 and D1081.
Adjusted transmitting signal through a buffer amplifier Q1117, Q1118, Q1119 and diode
switch D1099, D1101 sent to the preamplifier Q1132.
