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QUANZHOUBAOJIE ELECTRONICS CO.,LTD. Model:BJ-9900 CIRCUIT DESCRIPTION Receiver signal channel Main band 430MHZ Signal 430MHz signal transmits to Antenna through a high pass filter network, and a low pass filter network switching diode D1029,D1030{}and }D1001, then transmit to Main band RF amplifier Q1001 through another low pass filter network.
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QUANZHOUBAOJIE ELECTRONICS CO.,LTD. Model:BJ-9900 38.55MHz main band first IF signal is sent to the crystal filter FL1001 and FL1002. The crystal filter to remove those unwanted mixer products, and then sent to the IF amplifier Q1027 IF IC IC1044. Meanwhile the 13MHz Crystal part X1002 export the triple frequency via Q1042 to generate 39MHz second local oscillator signal and transimit to IF IC1044 where 39MHz second LO and 38.55MHz Main band first LO mixed to be 450KHz Main band...
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QUANZHOUBAOJIE ELECTRONICS CO.,LTD. Model:BJ-9900 RF amplifier Q1002 through another low pass filiter network. Amplified 430MHz signal transmits to Tuned vibration variable resistance filter network through the switch D1009,which include D1011.D1012 ,D1013 and related circuit. and then it transmits to the first mixer Q1005.Meanwhile UHF local oscillator signal which comes from UHF-VCO/AQ1123 transmit to the first mixer Q1003 and generate first IF of 49.95MHz Sub-band...
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QUANZHOUBAOJIE ELECTRONICS CO.,LTD. Model:BJ-9900 other signal except the useful and then transmit to ceramic discriminator CD1001 via the IF amplifier in IC1047.The ceramic discriminator will remove any Variance in Amplitude in 450KHz IF signal before voice detecting .The ceramic discriminator will remove any Variance in Amplitude in 450KHz IF signal before voice detecting .
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QUANZHOUBAOJIE ELECTRONICS CO.,LTD. Model:BJ-9900 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.
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QUANZHOUBAOJIE ELECTRONICS CO.,LTD. Model:BJ-9900 Amplified transmitting signal reaching Q1132 transmit to diode switch D1107 through the diode switch D1106 and drive amplifier, and finally be amplified by power amplifier Q1135 to generate more than 35W output power .These three steps are controlled by auto power control circuit.
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QUANZHOUBAOJIE ELECTRONICS CO.,LTD. Model:BJ-9900 430 MHz signal Part of the output of the power amplifier corrected by the D1121 and D1122,Then sent to the APC Automatic Power Control IC1129.As a DC voltage, APC Automatic Power Control of the power amplifier output level is proportional to.
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QUANZHOUBAOJIE ELECTRONICS CO.,LTD. Model:BJ-9900 then launch "PTT" command to the main CPU IC1104. When the "PTT" command is received, the main CPU IC1104 pin 45 to the "high" position, then activates the UHF transmitter switch Q1096. When the Q1096's UHF transmitter switch is activated, it controls the antenna switching diode D1118, D1119, D1120, modulation switching diode Q1114, Q1115, diode switch D1099, D1101, D1106, D1107, and APC automatic power switch Q1130, Q1131.
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QUANZHOUBAOJIE ELECTRONICS CO.,LTD. Model:BJ-9900 phase comparator. Come to the VHF-VCO / B Q1120 part of the output buffer amplifier Q1121 and through diode switch D1087, sent to the PLL IC1109 programmable divider. Here it is according to the main CPU IC1104 related to the frequency division data is divided and sent to the phase comparator.
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QUANZHOUBAOJIE ELECTRONICS CO.,LTD. Model:BJ-9900 in the reference divider is separated to form 5 kHz or 6.25 kHz reference frequency compared these baseline frequency will be utilized by the phase comparator. . IC1112 phase comparator circuit of the voltage controlled oscillator and the oscillation frequency of the frequency of the phase comparison between the frequency comparison.
QUANZHOUBAOJIE ELECTRONICS CO.,LTD. Model:BJ-9900 BLOCK DIAGRAM TX-RX UNIT FN0001 NOIZE-B SM-B CTR-B FL1001 IF AMP FAN CNTL RF AMP RF AMP RADIO IC FL1002 Q1027 SIGIN Q1076 Radio AF D1004 D1005 Q1003 IF IC PMR D/A IC IC1041 D1008 D1035...
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QUANZHOUBAOJIE ELECTRONICS CO.,LTD. Model:BJ-9900 CR2001 Crystal 14.7456MHz D2001 LCD BACKLIT D2002 White D2003 Diode HZM27WA D2004 Diode HZM27WA D2005 White D2006 White D2007 White D2008 White D2009 White D2010 White D2011 White D2012 White D2013 White D2014 White D2015 White...
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