MJ-327 VHF FM TRANSCEIVERS

Transcription

1 SERVICE MANUAL MJ- VHF FM TRANSCEIVERS

2 SPECIFICATIONS GENERAL Frequencyy Range Workingg Temperate --MHz -0 ~+ Operating Voltage DC.V Current Consumption.A(transmit W) Sensitivity Adjust Antenna impedance 0mV 0Ω TRANSMITTER Frequency Stability Output Power Maxx Frequency Deviation Audio Distortion Adjacent Channel Power Occupied Bandwidth RF Sensitivity : Audio Output ±ppm W(High),W(Low) KHz % -db KHz μv 0.W Audio Distortion 0% All stated specifications are subject to change without notice or obligation.

3 CIRCUIT DESCRIPTION. Frequency configuration The receiver utilizes double conversion. The first IF is.mhz and the second IF is 0kHz. The first local oscillator signal is supplied from the PLL circuit. The PLL circuit in the transmitter generates the ecessary frequencies. Fig. shows the frequencies.. Receiver The freauency configuration of the receiver is shown in Fig.. ) Front - end RF amplifier An incoming signal from the antenna is applied to an RF amplifier (T) after passing through a transmit/receive switch circuit (D,D,D) and a -pole LC filter(l,c).after the signal is amplified (T), the signal is filtered by a band pass filter (a -pole LC filter) (L0,C0,L,L) to eliminate unwanted signals before it is passed to the first mixer. The voltage of these diodes are controlled by to track the MPU(U) center frequency of the band pass filter. (See Fig. )

4 ) First Mixer The signal from the RF amplifier is heterodyned with the first local oscillator signal from the PLL frequency synthesizer circuit at the first mixer (T) to create a.mhz first intermediate frequency (st IF) signal. The first IF signal is then fed through crystal filters (FL,FL) to further remove spurious signals. ) IF amplifier The first IF signal is amplified by T, and then enters U (FM processing IC). The signal is heterodyned again with a second local oscillator signal within U to create a 0kHz second IF signal. The second IF signal is then fed through a 0kHz ceramic filter (FL) to further eliminate unwanted signals before it is amplified and FM detected in FL0. ) AF amplifier The recovered AF signal obtained from U goes to the microprocessor(u). The processed AF signal passes through an AF volume control and is amplified to a sufficient level to drive a loud speaker by an AF power amplifier (U). ) Squelch Part of the AF signal from the IC enters the FM IC again,and the noise component is amplified and rectified by a filter and an amplifier to produce a DC voltage corresponding to the noise level. The DC signal from the FM IC goes to the analog port of the microprocessor (U). U determines whether to output sounds from the speaker by checking whether the input voltage is higher or lower than the preset value.to output sounds from the speaker, U sends a high signal to the AF Power Iines and turns U on through T,T. ) Receive signaling QT/DQT The output signal from FM IC (U) enters the microprocessor(u).u determines whether the QT or DQT matches the preset value, and controls the AF Power and the speaker output sounds according to the squelch results. PLL frequency synthesizer The PLL circuit generates the first local oscillator signal for reception and the RF signal for transmission. ) PLL The frequency step of the PLL circuit is and.khz and so on. A 9.MHz reference oscillator signal is divided at U by a fixed counter to produce the or.khz reference frequency. The voltage controlled oscillator (VCO) output signal is buffer amplified by T0, then divided in U by a programmable counter. The divided signal is compared in phase with the or.khz reference signal in the phase comparator in U. The output signal from the phase comparator is filtrered through a low-pass filter and passed to the VCO to control the oscillator frequency. ) VCO The operating frequency is generated by T0 in transmit mode and T in receive mode. The oscillator frequency is controlled by applying the VCO control voltage, obtained from the phase comparator, to the varactor diodes (D0 and D in transmit mode and D0 and D in receive mode). The TC/RC pin is set low in receive mode causing T off, and turn T on. The TC/RC pin is set hight in transmit mode causing T off,and T9,T9 on.

5 ) UNLOCK DETECTOR FB If a pulse signal appears at the LD pin of U, an unlock condition occurs, and the DC voltage obtained from D09, and C causes the voltage applied to the PLL-LD pin of the microprocessor to go low. When the microprocessor detects this condition, the transmitter is disabled, ignoring the push-totalk switch input signal. ( See Fig.). Transmitter )Microphone Amplifier The signal from the microphone passes through U.The signal passes through the Audio processor(u) for the maximum deviation adjustment,and goes to the VCO modulation input. )Drive and Final Amplifier The signal from the T/R switch(d and D) is amplified by the pre-drive(t.t0) and drive amplifier(t) to 0mW.The output of the drive amplifier is amplified by the RF power amplifier(t) to.0w(w when the power is low).the RF power amplifier consists of two MOS FET stages.the output of the RF power amplifier consists of two MOS FET stages.the output of the RF power amplifier is then passed through the harmonic filter (LPF) and antenna switch (D,D)and applied to the antenna terminal.. Power supply There are four V power supplies for the microprocessor: M,C,R,and T,M for microprocessor is always output while the power is on.m for microprocessor is always output while the power is on.m is always output,but turns off when the power is turned off to prevent malfunction of the microprocessor. C is a common V and is output when SAVE is not set to OFF. R is V for reception and output during reception. T is V for transmission and output during transmission..control Circuit The control circuit consists of a microprocessor (U) and its peripheral circuits.it controls the T-R unit.u mainly performs the following: () Switching between transmission and reception by the PTT signal input. () Reading system,group,frequency,and program data from the memory circuit. () Sending frequency program data to the PLL. () Controlling squelch on/off by the DC voltage from the squelch circuit. () Controlling the audio mute circuit by the decode data input. () Transmitting tone and encode data.

6 )Memory Circuit Memory circuit consists of the CPU (U) and an EEPROM(U).An EEPROM has a capacity of K bits that contains the transceiver control program for the CPU and data such as Transceiver channels and operation features )Low Battery Warning The battery voltage is checked using by the microprocessor. () The red LED blinks when the battery voltage falls below.v. () A Warning tone generates when the red LED blinking. ( See Fig.)

7 ADJUSTMENT Required Test Equipment The following items are required to adjust radio parameters:. Regulated power supply Supply voltage: -V DC Current: A or more. Digital multimeter Voltage range: FS = Approx. 0V Current: 0A or more Input resistance: High impedance. Oscilloscope Measurable frequency: Audio frequency. Audio dummy load Impedance: ohm Dissipation: W or more Jack:.mm. SSG Output frequency: 00MHz or more Output level: -0dBu/0.uV -0dBu/V Modulation: FM. Spectrum Analyzer Measuring range: Up to GHz or more. Power meter Measurable frequency: Up to 00MHz Impedance: 0, unbalanced Measuring range: 0.W -0W. Audio volmeter Measurable frequency: Up to 00KHz Sensitivity: mv to 0V 9. Audio generator Output frequency: Hz to 0KHz

8 Output impedance: 00, unbalanced 0.Distortion meter/sinad meter Measurable frequency: khz Input level: Up to 0dB Distortion: % - 00%.Frequency counter Measurable frequency: Up to 00MHz Measurable stability: Approx. +/-0.ppm.Linear detector Measurable frequency: Up to 00MHz Characteristics: Flat CN: 0dB or more Note Standard modulation: khz +/-.khz/dev Reference sensitivity: db SINAD Specified audio output leve: 00mW at

9 00P 0P 0P 0P 0P 0P 0P 0P 0P P P P P P P P P 0P 0P 9P 0P 00K 0 0K 0K K 0KD 0K K K K K 00 Capacitance C9. C. C. C. C. C. C. C. C9. C0. C 00 Capacitance C. C0. C. C9. C0. C. C0. C90 C0. C. C0. C. C. C9. 00 Capacitance C9. C. C9. C. C. C. C. C. C9. C9 00 Capacitance C. C0. C. C. C. C. C0. C. C0. C. C 00 Capacitance C. C 00 Capacitance C 00 Capacitance C. C9 00 Capacitance C 00 Capacitance C. C. C 00 Capacitance C0. C. C9 00 Capacitance C. C 00 Capacitance C. C. C 00 Capacitance C 00 Capacitance C. C9. C. C0. C. C0. C. C. C. C. C. C9 00 Capacitance C. C. C 00 Capacitance C0. C 00 Capacitance C 00 Capacitance C 00 Capacitance C 00 Capacitance C 00 Capacitance C 00 Capacitance C 00 Resistor R 00 Resistor R0. R. R0. R. R 00 Resistor R. R0. R. R. R. R 00 Resistor R. R. R. R9. R. R. R. R. R0. R. R909. R90 00 Resistor R0 00 Resistor R. R9 00 Resistor R 00 Resistor R9. R9. R9. R9. R9. R9 00 Resistor R 00 Resistor R0 00 Resistor R. R. R9. R. R9. R900. R90 00 Resistor R. R 00 Resistor R

10 M M 00K 0K K K K K 0K K K 90K 9K K K9 K K K K 0K K K 9 K UF UF UF 0UF 0UF 0T GREEN RED SS DAN SK DTAEE DTCEE MRF9 SB C CHORD LM 00 Resistor R. R. R 00 Resistor R. R 00 Resistor R 00 Resistor R9 00 Resistor R0. R 00 Resistor R 00 Resistor R 00 Resistor R. R 00 Resistor R. R. R9. R 00 Resistor R. R. R. R. R. R 00 Resistor R. R 00 Resistor R 00 Resistor R. R 00 Resistor R. R. R 00 Resistor R 00 Resistor R 00 Resistor R0. R9. R. R. R 00 Resistor R0. R. R. R. R. R. R 00 Resistor R 00 Resistor R. R 00 Resistor R 00 Resistor R0 00 Resistor R 00 Resistor R. R 00 Resistor R 0 Resistor R. R. R 0 Resistor L 00 Pol-Cap E 00 Pol-Cap E 00 Pol-Cap E. E. E. C9 A Pol-Cap E. E9 B Pol-Cap E9 00 Ind L0. L 00 G-LED D 00 R-LED D USM Diode D USM Diode D ESM Transistor T. T ESM Transistor T0 ESM Transistor T USM Transistor T TSM Transistor T0 SO IC U SO IC U SO IC U

11 LM LM90V F A MHZ 0K MONI PTT SCR JP Bottom Comment 0P 00P 0P 0P 0P 0P 0P P P P P P 0P 0P P P P P P 0P P P SO IC U SSOP IC U SSOP IC U SOT9 IC U9 F-CS0 Oscillator CR Var-Res RV. RV Button SW Button SW Button SW Connectors JP Footprint Name Designators Quantity 00 Capacitance C. C. C C. C. C. C. C. C. Capacitance C. C C. C. C9. C0. C. C. Capacitance C. C. C. C. C. C. C C. C. C. C. C9. C. Capacitance C0. C. C. C. C0. C. C. C. C. C9. C. C. 0 C. C C0. C. C. C. C. C. Capacitance C. C. C. C. C9. C. C9. C. C. C0. C0. C. 00 C0. C. C. R 00 Capacitance C 00 Capacitance C. C. C. C9. R. VC C. C. C. C. C0. C. 00 Capacitance C 00 Capacitance C. C. C. C 00 Capacitance C 00 Capacitance C. C9 00 Capacitance C. VC0 00 Capacitance C. C 00 Capacitance C. C. C 00 Capacitance C 00 Capacitance C 00 Capacitance C. C. C9 00 Capacitance C 00 Capacitance C. C 00 Capacitance C. C 00 Capacitance C. C. C 00 Capacitance C. C. C

12 C0. C. C. C. C. C. C. C. C. C. C0. C. 00 Capacitance C. C. C. C0. C. C. 9 C. C. C. C9. C9. C9. C9. C. C0. C. C90 P 00 Capacitance C P 00 Capacitance C P 00 Capacitance C9. C0. C P 00 Capacitance C P 00 Capacitance C. C9 P 00 Capacitance C0 P 00 Capacitance C. C. C9. C9 P 00 Capacitance C 9P 00 Capacitance VC 0P 00 Capacitance L 0P 00 Capacitance C. C90 0P 00 Capacitance C. C P 00 Capacitance C 00 Capacitance C. L P 00 Capacitance C P 00 Capacitance C 0P 00 Capacitance C P 00 Capacitance C P 00 Capacitance C P 00 Capacitance C 00 Resistor R. R. R00. R 00K 00 Resistor R. R9. R0. R. R. R. R. R. R Resistor R. R. R9. R9. R 0K 00 Resistor R9. R. R. R. R0. R. R. R0. R. R90. R90 00 Resistor R. R9. C 0K 00 Resistor R. R. R. R9 0K 00 Resistor R. R 00 Resistor R. R K 00 Resistor R. R 0K 00 Resistor R. R K 00 Resistor R. R. R. R. R90. R90. R90. R90. R90 9 K 00 Resistor R K 00 Resistor R K 00 Resistor R0 M 00 Resistor R. R 00K 00 Resistor R. R0

13 0K K R 0K K 0K K R 9K K K9 0K K R K K K 0K R K 0UF UF UF UF UF 0UF 00NH 0NH 90NH 0NH 0NH 0NHD UH 0T 0T NH R0 R 00 Resistor R 00 Resistor R. R9. R. R. R9 00 Resistor R 00 Resistor R. R. R. R 00 Resistor R 00 Resistor R. R 00 Resistor R. R. R. C 00 Resistor R 00 Resistor R. C 00 Resistor R. R 00 Resistor R 00 Resistor R 00 Resistor R. R. R. R9. R9. R9. R99. R 00 Resistor R 00 Resistor R. R 00 Resistor R. R. R0. C 00 Resistor R0. R. R. R. R 00 Resistor R. R. R 00 Resistor R0. R. R. R 00 Resistor R 00 Resistor R 00 Resistor R9. R 00 Resistor R 00 Resistor L. R 00 Resistor R 00 Resistor L9. L 00 Resistor R. R. L 00 Pol-Cap E. E 00 Pol-Cap E9. E 00 Pol-Cap E 00 Pol-Cap E. E. E0 A Pol-Cap E A Pol-Cap E 00 Ind L. L. L. L0. L. L 00 Ind L. L. L. L9. L9 00 Ind L 00 Ind L. L 00 Ind L 00 Ind L 00 Ind L. L 00 Ind L. L 00 Ind L. L. L90 00 Ind L. L. L. L. L 00 Ind L. L 00 Ind L. L. L

14 R T T T T T T HSC MAS SS SV0 B9 MA SC SJ DTAEE DTCEE SC SC0(Y) KTC0 R UMC SB SK0NV RN SC9 SK SK0 SK SK0 MCU TAF TAF LM MHZ K 0K BAT 00 Ind L 0.*.mm Coil-Ind L 0.*.mm Coil-Ind L 0.*.mm Coil-Ind L. L 0.*.mm Coil-Ind L 0.*.mm Coil-Ind L 0.*.mm Coil-Ind L ESC Diode D. D. D. D ESC Diode D. D USC Diode D USC Diode D USC Diode D. D9. D. D USM Diode D ESM Transistor T ESM Transistor T ESM Transistor T. T0. T ESM Transistor T0. T9. T. T. T. T USM Transistor T. T USM Transistor T9 USM Transistor T. T USM Transistor T9 USV Transistor T TSM Transistor T0. T0 TSM Transistor T. T TSV Transistor T SOT9 Transistor T SOT9 Transistor T SOT9 Transistor T SOT Transistor T. T HWSON- Transistor T QFP IC U SSOP0 IC U SSOP IC U SSOP0 IC U Oscillator CR Oscillator CR Filters FL Battery BAT

15 EPLODED VIEW A 0 B A B B B C C C C C C C C

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20 K K K 00P K 0P0P LCD C0 C 00P /RD /WR 00P DATA VSS OSCO OSCI VLCD VDD C C HVU ANT P P P P P P P 0P 0.*.*T T P 0NH( 叠 层 ) UH P 9 0.*.*T 0.*.*T 0.*.*T HSC HSC P NH( 绕 线 ) NH VHF P R( 绕 线 ) P 00K R NH( 绕 线 ) R 0P P SK(YK-) P NH( 绕 线 ) 0P 9P P NH( 绕 线 ) 9P 0P 0K P 0nH( 叠 层 ) TP 0P 0 R( 绕 线 ) SK(YK-) P R( 绕 线 ) 0P 0P M0 9P M0 0P 0 0K R 0 K SC(QY) 0UF P SC(QY) 0P 0K TAFN 0P P 00P 0P 0K K 0C DTAEE 0P P TP 0NH R 0P P 0 0NH 0K 0P P 0K 0P 0 0K K9 0K P K TP K K K P P 0P 0μF 0K SQ P N/W RI VCC SW-VOL P 0P VCC 0P 0P K SB 0UF 9 0K 0K 0P 0 9 TAF K DTCEE() 00P P SK(NG) 0UF 0P DTCEE() BAT VCC BATT 0UF 0P 0P K SP JACK K SP 00P C P P P P M P K N.U. 0P K 0P 0K P K 0P K 0P 00K 0P 00K K K 9P M FUSE PB 00NH( 磁 珠 ) UF SR-00 0P 0P P P P P P VCC P C 0T( 磁 珠 ) R K SC(BR) UF DC SW MAS UMC 00K K C RVCO SJ HSC HSC K TVCO K K P 0nH( 叠 层 ) R 0 C K K P 0 P R 0nH( 叠 层 ) R 0 0K 00P 0P 0nH( 叠 层 ) 0P 0P 0P 0P R0( 绕 线 ) P K 0P K R( 绕 线 ) P SV0 0P P R_VCO P K P R0( 绕 线 ) T_VCO P R( 绕 线 ) 0P P 00K 0P B9 B9 B9 B9 0 μh( 磁 珠 ) 0P K μh( 磁 珠 ) 00P 00nH C 0K K K μf 0μF K 0μF TP M 0P P 0P K 0K 0P AUR F/M 00K 00K 00K K 0P 0P 0K 00K 0P K K 0P 0P 0P 0K 0P 0 9 P SK(B) P TONE 0P 0P K V 90K CHORD K 00K DATA CLK R-ANI 0P VR 00K 0P 0P K9 0K LM K K 0K 0K LM K 0P 0K VR 0K P K 0P AUR 0.*.*T P K(B) 0K(B) 0K(B) VCC 0T( 磁 珠 ) 0T 0K(B) RQA000 0K(B) LM90() VCC P K 0K(B) 0P 0P NH( 叠 层 ) R 00P T DTCEE 9K 0K 0P P K 0K 0P 0P K P 0P SK0(UW) M 0K 0UF 0P R0J( 绕 线 ) 0T( 磁 珠 ) R K 0P LM90() 0P 0K DTCEE K R 0K 0P 0P 0P SC(RF) P APC PB PB PB 90NH( 磁 珠 ) V T 00NH( 叠 层 ) R 0P K9 K P 9 /CS 0 /IRQ S0 R 00NH( 叠 层 ) SC(R) S0 BI S K 0K S /BI S S LCD Driver C0 C C 0P C C 0NH( 叠 层 ) 00K S 0P S S S0 S S9 0P 9 S9 R 0 S0 U S P P S S S S S S S S K 0 CLK PB P0 K DTCEE() OUT DATA PB K IN STB P9 LED 00P Fin 三 色 背 光 灯 PC0 GND LM 00P Fin GDN 00P LED BACK_LIGHT DTCEE() CP CP 0P VP VP 9 00P VCC VCC 0 N N LED(R) VCC 0P LED LED VCC R 00nH( 叠 层 ) DTCEE() UF LED LED LED(G) DTCEE() 0P 0P C 键 盘 灯 LED FOUT VCC 0P PC 9M 0P LED BACK_LIGHT GND VT 0K P 9K K K QT/DQT P P P P P P0 PC0 PC PC TONE UF K K K PC MICO MICI VSS V 0P 0P 9 0 VDD K P P P P P 0T T-ANI P P L L C TONE K K K P 0 0P O U T P 0P 9 P P MCU IN TP K K P P 9 P P A V S S AUR 0K /R E S E T P P A V D D 0 M P P K C 0P R 00K R 00K D N.U. MAS 0 9 0T P9 P9 P9 P9 P9 P9 P9 P90 PB PB PB RI 0P RO K 0P 0K V 0P SC(BR) RNC-TR-FA out Gnd in T C K K K K P90 P9 P9 P9 P9 0K V T M 0P V 0P K P C 0P K K K P K PB SC(BR) 0K N N N N N 0K 0K P M 0P ALARM MONI 9 D V T 0P K P DTCEE() K O < 0P K K 0 N/W * 0 # K 0P T () K > A B C 0K K 0P T UF VCC K P 0K 0K 0K P T 0UF 0P 0P SB(BV) V 0P VCC MA 0P () K 0P Vin μf P 0K SC A GND K 0P 0P 0P Vout R 0UF P K SS(N9) V P K μf V 0K 0P K V DTAYE 00K SB(BV) 0P 0P UF VO K 0P SC(L) V K 0T( 磁 珠 ) 0P 0UF V K K K K C 0UF V K 00K 0P SB(BV) 0P 0 0P 0P K 0 0 V MIC MIC JACK 0 PTT K 0K V SW-CH 0P P P P P P9 P9 P