TKR851.pdf

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1、 2004-5 PRINTED IN JAPAN B51-8684-00 (N) 987 UHF FM REPEATER TKR-851 SERVICE MANUAL UHF FM REPEATER TKR-851 Front panel (A62-0934-03) Knob (DC source) (K29-9106-04) Key top (K29-5460-02) Knob (Volume) (K29-5389-03) Modular jack (E08-0877-05) Antenna cable (N) (E30-7528-05) Antenna cable (BNC) (E30-3

2、418-05) TEST/SPKR connector assy (E37-0913-05) D-sub cable assy (E37-0904-05) DC backup terminal (E70-0402-05) DC cord (Ext DC in) (E30-3414-05) Fuse (Blade, 10A/32V) (F06-1032-05) x 2 GENERAL . 2 SYSTEM SET-UP . 2 OPERATING FEATURES . 3 REALIGNMENT. 4 INSTALLATION. 5 MODIFICATION . 8 DISASSEMBLY FO

3、R REPAIR . 10 CIRCUIT DESCRIPTION. 11 SEMICONDUCTOR DATA. 18 COMPONENTS DESCRIPTION. 20 PARTS LIST. 22 EXPLODED VIEW . 34 PACKING. 36 ADJUSTMENT. 37 CONTENTS TERMINAL FUNCTION . 46 INTERCONNECTION DIAGRAM. 50 PC BOARD FINAL UNIT (X45-3742-71). 52 DISPLAY UNIT (X54-3330-21) . 56 TX-RX UNIT (X57-6962-

4、70) (A/2). 60 TX-RX UNIT (X57-6962-70) (B/2). 64 RX VCO UNIT (X58-4800-10) . 68 TX VCO UNIT (X58-4810-10). 69 SCHEMATIC DIAGRAM . 70 BLOCK DIAGRAM. 83 KES-5 (EXTERNAL SPEAKER). 86 SPECIFICATIONS. 87 TKR-851 2 GENERAL / SYSTEM SET-UP INTRODUCTION SCOPE OF THIS MANUAL This manual is intended for use b

5、y experienced techni- cians familiar with similar types of commercial grade commu- nications equipment. It contains all required service informa- tion for the equipment and is current as of this publication date. Changes which may occur after publication are covered by either Service Bulletins or Ma

6、nual Revisions, which are issued as required. ORDERING REPLACEMENT PARTS When ordering replacement parts or equipment informa- tion, the full part identification number should be included. This applies to all parts : components, kits, and chassis. If the part number is not known, include the chassis

7、 or kit number of which it is a part and a sufficient description of the required component, for proper identification. PERSONAL SAFETY The following precautions are recommended for personal safety : DO NOT transmit until all RF connectors are secure and any open connectors are properly terminated.

8、SHUT OFF this equipment when near electrical blasting caps or while in an explosive atmosphere. This equipment should be serviced by only qualified tech- nicians. SERVICE This radio is designed for easy servicing. Refer to the schematic diagrams, printed circuit board views, and align- ment procedur

9、es contained in this manual. Merchandise received Choose the type of transceiver Installation in the optional space Frequency range (MHz) TX/RX 440470 TX/RX 450480 RF power 25W 25W Type E K See page 4. A personal computer (IBM PC or compatible), programming interface (KPG-46), and programming softwa

10、re (KPG-91D) are required for programming. See page 40. The RX RF BPF (L2,L4,L5 on TX-RX unit A/2) must be aligned to obtain the maximum sensitivity at a programmed frequency. YES NO DC power supply or duplexer? KES-4 or KES-5 installation YES NO External speaker? Repeater programming Wide, XF1; Nar

11、- row) to further remove spurious signals. W/N SQL DET TX-RX unit (X57 A/2): TX-RX SW SW W/NW/N MCF (Narrow) XF1 MCF (Wide) XF2 RSSI QUD W/N SW DET VCO A VCO B RX VCO A3 (X58-480) RX ANT BPF L2 RF AMP Q1 BPF L4,L5 1st MIX DBM A1 IF AMP Q8 IF AMP Q9 IF AMP Q10 LPF IF AMP Q2 44.85MHz D1 D2 IF AMP Q3 F

12、M SYSTEM IC IC9 SWSW NOISE DET D5 NOISE AMP Q7 D3 D4 X1 44.395MHz CF1 (Wide) CF2 (Narrow) Q4 fRX44.85MHz DEI DEO RD CODEC RA RXI RXO DAC AMP IC608 AMP IC619 (B/2) LPF IC619 (A/2) AINRAOUTR CPU IC614 IC604 IC615 SW IC622 MUTE Q606 AM SPM AF AMP INT SP IC629 RSSI ASQ TX-RX unit (X57 B/2): Control 455k

13、Hz 44.850MHz IC621 Q605INV Fig. 1Receiver circuit CIRCUIT DESCRIPTION TKR-851 12 2-3. IF Amplifier The first IF signal is amplified by Q2 and Q3, and then en- ters IC9 (FM system IC). The signal is heterodyned again with a second local oscillator signal (44.395MHz) with in IC9 to become a 455kHz sec

14、ond IF signal. The second IF signal is fed through a 455kHz ceramic filter, CF1 (Wide), CF2 (Nar- row) to further eliminate unwanted signal, and the quadrature detection circuit FM-detects the signal to produce a base- band signal and output it from pin 11. 2-4. Audio Amplifier The audio amplifier c

15、ircuit is located in control section of TX-RX unit (X57-696 B/2). The recovered audio signal ob- tained from IC9 is amplified by IC608, input to the AINR ter- minal of CODEC IC (IC614), and audio processed by DSP (IC618). The processed audio signal from AOUTR terminal of IC614 is amplified by IC619

16、(B/2) to a sufficient level, anti- aliasing filtered by IC619 (A/2). The audio signal goes to an electronic volume (IC615) V3/V4, to the input of multiplexer IC (IC622), and is amplified to drive a loudspeaker by an audio power amplifier (IC629). The 4W audio output can be pro- vided to external 4 o

17、hms speaker through the 15-pin test con- nector “SPO, SPG” on the rear panel. 2-5. Squelch Circuit The output signal from IC9 enters FM IC again, then passed through a band-pass filter. The noise component output from IC9 is amplified by Q7 and rectified by D5 to produce a DC Voltage corresponding t

18、o the noise level. The DC voltage is sent to the analog port of the CPU (IC604). IC9 outputs a DC voltage (RSSI) corresponding to the in- put of the IF amplifier. 3. Transmitter Circuit The transmitter circuit consists of the following circuits : 3- 1 microphone circuit, 3-2 modulation level adjustm

19、ent circuit, 3-3 driver and final power amplifier circuit, 3-4 automatic power control circuit, 3-5 RF power down detect, and 3-6 fan action control circuit. 3-1. Microphone Circuit The signal from the microphone is passed through AGC circuit located in display unit (X54-333), so that it does not sa

20、turate. This circuit consists of IC501, D501, D502, Q501, and Q502. The AGC is operated by controlling the + and side levels of amplitude using the current obtained by posi- tive and negative detection of the amplified audio signal. The audio signal goes to control section of TX-RX unit (X57-696 B/

21、2) from display unit (X54-333). The transmit audio signal goes to the input of the multi- plexer IC (IC605) for microphone muting. The audio signal is amplified by IC610, input to the AINL terminal of CODEC IC (IC614), and audio processed by DSP (IC618). The processed audio signal from the AOUTL ter

22、minal of IC614 is amplified by IC616 (A/2) to a sufficient level, anti-aliasing filtered by IC616 (B/2), and amplified by the summing amplifier IC611 (A/2). 3-2. Modulation Level Adjustment Circuit The output of the summing amplifier IC611 (A/2) is passed to an electronic volume (IC615) for maximum

23、deviation ad- justment before being applied to a varactor diode in the volt- age controlled oscillator (VCO) A2 located in TX-RX unit (X57- 696 A/2). TXRX unit (X57 B/2): CONTROL MIC CODEC ICMOSW MIS TA TXO TXI MB D-SUB TD DAC SW TDS TAS AINLAOUTL SW MIC JACK J601 Display unit (X54 B/2) AMPATT DET M

24、IC Display unit (X54 A/2) IC501(A/2)Q501,502 D501,502 VR501 IC605 (A/2)IC610IC614 IC616 (B/2) IC616 (A/2) IC605 (B/2) IC615 AMPAMP IC611 (A/2) AMPLPF Fig. 2Microphone circuit CIRCUIT DESCRIPTION TKR-851 13 3-3. Driver and Final Power Amplifier Circuit The transmit signal is generated by the TX VCO (

25、A2), am- plified by Q11, and sent to final unit (X45-374). This amplified signal is amplified by Q1, Q2, Q3 and Q4, and is passed to the FINAL stage. The RF power amplifier consists of MOS FET. TEMP Final unit (X45-374 A/2) PC POWER ADJ Vcont TX ANT ATT TCXO FCT X3 16.8MHz BUFF IC1 MB MO TX-RX unit

26、(X57-696 A/2) CM COUPLER REF AMP DC AMP VR1 SW STT Q11 Q1 Drive AMP Q4 Drive AMP Q3 Drive AMP Q5 Final AMP IC3 IC3 Q8 D4D5 Q2 Drive AMP TX VCO A2 (X58-481) FWD DET REV DET PDT (to IC604 CPU) Fig. 3Driver and final power amplifier circuit 3-4. Automatic Power Control, Circuit and Transmitter The auto

27、matic power control (APC) circuit stabilizes the transmitter output power at a pre-determined level, and con- sists of forward/reverse power detector circuits, and switch- ing transistor Q8. The forward/reverse power detector cir- cuits detects forward RF power and reverse RF power to DC voltage, an

28、d consists of a CM coupling type detection circuit formed by a strip line, RF detector D4/D5, and DC amplifier IC3 (A/2). The voltage comparator (IC3 B/2) compares the above de- tected voltage with a reference voltage, set using the micro- processor and IC6 located in the TX-RX unit. An APC voltage

29、proportional to the difference between the sensed voltage and the reference voltage appears at the output of IC3. This output voltage controls the gate voltage for the drive amplifi- ers Q3 and Q4 and final amplifier Q5, which keeps the trans- mitter output power constant. 3-5. RF Power Down Detect

30、When the transmitter output power has dropped to or be- low the preset values (High Power : 10 W, Low Power : 0.4 W) in “RF Power Down Detect” adjustment, IC604 (CPU : X57-696) detects the drop in power and outputs a Low-level (default) signal to the AUX out port. 3-6. Fan Action Control Circuit If

31、fan action is set to “Temperature”, the cooling fan is turned ON or OFF according to temperature. If the ambient temperature of the final unit exceeds approx. 35C, the output from the temperature detection IC1 changes from H to L. This signal is sent to the CPU (IC604) by Q602 in the TX-RX unit B/2

32、(control section), and the out- put from pin 13 (FAS) of IC7 in the TX-RX unit A/2 controlled by the CPU goes H. FAG FAB CN4 Q9 TMP FAS IC1 13 Q6 IC7 CK, DT, STB CPU IC604 TMP 17 Q602 +B X45 A/2X57 A/2X57 B/2 FAN OFF ON +20C+30C+35C +40C+50C This signal turns Q9 in the final unit ON to run the cooli

33、ng fan. It has a hysteresis of approx. 2C by IC1. If fan action is set to “Continuous”, the fan operates continuously, but Q9 stays ON. Fan operation Fig. 4Fan action control circuit CIRCUIT DESCRIPTION TKR-851 14 4. PLL Frequency Synthesizer The PLL frequency synthesizer circuit consists of the fol

34、- lowing circuits : 4-1 receiver PLL circuit, 4-2 transmitter PLL circuit, and 4-3 unlocked detector circuit. 4-1. Receiver PLL The receiver PLL circuit is located in VCO unit A3 (X58- 480) on TX-RX unit (X57-696 A/2), and consists of VCXO X2, VCOs (Q350 and Q351), a single-chip PLL IC IC300, buffer

35、 amplifier Q355, and high-frequency amplifier Q302. The VCXO generates 16.8MHz. The frequency stability is within 1.5ppm (Temperature range of 30 to +60C). The frequency tuning of the VCXO is done to apply a voltage to pin 1 of the VCXO. The output of the VCXO is applied to pin 8 of the PLL IC throu

36、gh the pin 7 of the VCO. The first local oscillator is a lower heterodyne local oscilla- tor, and the VCO oscillator frequency is 405.15 to 435.15MHz (K), 395.15 to 425.15MHz (E). The oscillator frequency is controlled by applying the VCO control voltage, obtained from the phase comparator to the va

37、ractor diodes. 4-2. Transmitter PLL The transmitter PLL circuit is located in VCO unit A2 (X58- 481) on TX-RX unit (X57-696 A/2), and consists of VCXO X3, VCOs (Q350), a single-chip PLL IC IC300, buffer amplifier Q355, and high-frequency amplifier Q302. The VCXO generates 16.8MHz. The frequency stab

38、ility is within 1.5ppm (Temperature range of 30 to +60C). The frequency tuning and modulation of the VCXO are done to apply a voltage to pin 1 of the VCXO. The output of the VCXO is applied to pin 8 of the PLL IC through the pin 7 of the VCO. The VCO oscillator frequency is 450.00 to 480.00MHz (K),

39、440.00 to 470.00MHz (E). The oscillator frequency is controlled by applying the VCO control voltage, obtained from the phase comparator to the varactor diodes. 4-3. Unlock Detector Circuit If a pulse signal appears at the LD pin of IC300, an unlock condition occurs, causing the voltage applied to th

40、e pin of the microprocessor to go low. The names of this pin are LDT for TX PLL and LDR for RX PLL. When the microprocessor de- tects this condition, the transmitter is disabled. Q351 VCO unit (X58-480) SRR VCO A IC300 VCO B Q355Q350 Q354 Q352 Q353 Q300Q302 VCXO X2 TX-RX unit IC604 SW SW SW AMP AMPL

41、PFPLL-IC -com CP,DP EPR,LDR VCO unit (X58-481) VCO A IC300 Q355Q350 Q300Q302 VCXO X3 TX-RX unit IC604 AMP AMPLPFPLL-IC -com CP,DP EPT,LDT MO MOMO Fig. 5Receiver PLLFig. 6Transmitter PLL VCO A : 450480 (K) 440470 (E) Top view TX VCO (X58-481) VCO A : 440460 VCO B : 460480 RX VCO (X58-480) (MHz) 44.85

42、0 44.850 Fig. 7VCO oscillation frequency CIRCUIT DESCRIPTION TKR-851 15 5. Control Circuit The control circuit mainly located in the control section of TX-RX unit (X57-696 B/2) consists of the following : 5-1 CPU, 5-2 memory circuit, 5-3 CPU clock shift, 5-4 shift register cir- cuit, 5-5 display cir

43、cuit, 5-6 DSP circuit, 5-7 base-band circuit, 5-8 RS-232C circuit, 5-9 power supply circuit, and 5-10 5-tone decode circuit. 5-1. CPU The CPU (IC604) is a 16bit single-chip microcomputer con- taining a 32k ROM and 3k RAM. This CPU controls the flash ROM, the DSP, the receiver circuit, the transmitte

44、r circuit, the control circuit, and the display circuit and transfers data to or from an external device. 5-2. Memory Circuit IC609 has a flash ROM with a capacity of 2M bits that contains the control program for the CPU, the signal process- ing program for DSP and data such as channels and operatin

45、g features. This program can be easily written from an external de- vice. Data such as the operating status are programmed into the EEPROM (IC600). 5-3. CPU Clock Shift There are the 14.754MHz clock for the CPU (IC604) and the 16.515MHz clock for the DSP (IC618) at the control sec- tion of TX-RX uni

46、t (X57-696). When these clocks are multi- plexed with the reception frequency, they become an inter- nal beat signal. To prevent this, by tuning Q600 and Q604 on the clock frequency is shifted. (Shift on/off can be set through programming.) 5-4. Shift Register Circuit Serial data is sent to the shift register (IC502 to IC505 lo- cated in display unit, IC602, IC623, IC7 located in TX-RX unit) from the CPU (IC604) to control