Service_Manual_TTI_TCB-550_ENG.pdf

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1、SERVICE MANUAL MULTI CHANNEL AM/FM TRANSCEIVER TCB-550 TTI Tech Downloaded from www.cbradio.nl SECTION1SPECIFICATIONS SECTION2CIRCUIT DESCRIPTION 1GENERAL 2TECHNICAL DESCRIPTION 3SEMICONDUCTORS AND FUNCTION 4DESCRIPTION OF FREQUENCY DETERMINING AND STABILIZING CIRCUIT 5TEST EQUIPMENT SETUP AND ALIGN

2、MENT INSTRUCTIONS SECTION 5-3LED PCB 3PART LIST SECTION 5-1MAIN PCB 5-2 5-4VOLUME PCB 5-5MIC PCB FRONT PCB 4MECHANICAL DISASSEMBLY SECTION5BOARD LAYOUT SECTION6BLOCK DIAGRAM SECTION7SCHEMATIC TABLE OF CONTENTS SECTION1 SPECIFICATIONS Channel Frequency Range Operating mode Frequency Control Frequency

3、 Tolerance Operating Temperature Range Microphone Input Voltage Size Weight Antenna Connector Power Output Modulation Frequency Response Output Impedance Harmonic Suppression Current Drain Receiving System IF Frequencies Sensitivity Audio Output Power Audio Distortion Image Rejection Adjacent Channe

4、l Rejection Conducted Spurious Frequency Response Built-in Speaker Squelch * Specification is subject to change without prior notice. T R A N S M I T T E R R E C E I V E R G E N E R A L 40 (See the frequency band chart) 26.56 MHz 28.00 MHz F3E (FM), A3E (AM) PLL Synthersizer 0.002% -10 to + 55 C Plu

5、g-in Type 13.2V DC 15% 124 (W) x 135 (L) x 37 (H) 655 g Antenna Connector Duty cycle 10% 4 Watts 13.2V DC AM:from 85% to 95% FM:1.8KHz 0.2KHz 300Hz to 3000Hz 50ohms, Unbalanced More than -36dBm AM Full Mod. 1.6A Max. Dual conversion superheterodyne Double Conversion 1st 10.695MHz/2nd 455KHz 0.7 V fo

6、r 10dB(S+N)/N in AM Mode 0.5 V for 20dB SINAD in FM Mode 2.0W 8 Ohm Less then 8% 1KHz 60 dB 60 dB More than 60 dB 300 to 2500Hz 8 Ohms, round Adjustable; Threshold less than 1 microvolt - Contents - 1 General 1-1. Receiver 1.2. Transmitter 2. Technical Description 2-1. General 2-2. Type of emission

7、2-3. Frequency Table 2-4. RF Power Output 2-5. DC input Voltage and Current with 13.2V DC Input to Power AMP 2-6. Receiver IF and Local Oscillator Frequencies 3. Semiconductors and Function 4. Description of Frequency Determining and Stabilizing Circuit 4-1. Introduction 4-2. Basic Synthesis Scheme

8、4-3. Descriptions of Each Block 4-3-1. Introduction 4-3-2. Reference Frequency 4-3-3. VCO 4-3-4. Programmable Divider and its Control 4-3-5 Phase Detector and VCO Control 4-3-6. Transmitter / Receiver Buffer AMP 4-3-7. Transmitter Doublers 4-3-8. Switching of Turning Capacitor in VCO 4-3-9. Receiver

9、 Local Oscillator Outputs 4-4. Frequency Stability 4-5. Description of other Circuits 4-5-1. Transmitter 4-5-2. Receiver 5. Test Equipm VCO Section Transmitter Section Receiver Section Test Data Schematic Diagram Block Diagram PCB Map PARTS LIST ent Setup and Alignment Instructions 5-1. 5-2. 5-3. 6.

10、 7. 8. 9. 10. SECTION2 CIRCUIT DESCRIPTION 1. General 1-1. Receiver Display : 40 Channels and other functions indication Frequency Range : 26.965 to 27.405 MHz Frequency Response : 300 to 2,500 Hz Power Source : 13.2 V DC Audio Output Load : 8 OHM Resistive Audio Output : 4.0 W (or More) Squelch : A

11、djustable from 0.2uV to 1 mV Sensitivity : - FM : 20 dB SINAD under 1.0 uV or less - AM :10 dB S/N under 1.0 uV or less Intermediate Frequency : - 1st IF : 10.695 MHz - 2nd IF : 455 KHz 1-2. Transmitter Carrier Power(Conducted) : AM 1 W / FM 4.0 W Current Drain ( 13.2 V Supply Voltage) - No Modulati

12、on : 1,100 mA (No Modulation) - Max Modulation : 1,400 mA (Full Modulation) Modulation Capabilities - AM : +/- 90 % - FM : +/- 1.8 KHz/Dev Spurious Radiation : Less then -74 dBc Antenna Impedance : 50 OHM Frequency Tolerance : 0.002 % 2. Technical Description 2-1. General Model CB-550 is an mobile t

13、ype AM/FM radio transceiver for use of the Citizen Radio Service. Front Panel Controls LCD Display(Cannel ,RX,TX,AQ,SCAN,AM,FM,EMG Indicator). Receiver Audio Control (With Power ON/OFF Control) Volume Squelch Control Volume (S/W ON : TIGHT, S/W OFF : AUTO SQ) RF Gain Control Volume CHANNEL UP/DOWN T

14、ACT SWITCH. AM/FM TACT SWITCH EMG TACT SWITCH Accessable Connectors Antenna Jack External Speaker Jack External Power Cord Microphone Jack. Transmitter Power AMP - VOLTAGE 12.5 V Current 820mA Transmitter DRIVER AMP -VOLTAGE 12.5 V Current 130mA 2-2. Type of em 2-3. Frequency Range : 26.965 MHz (CH.

15、1) - 27.405 MHz (CH.40) 2-4. RF Power Output : AM/FM 4.0 Watts 2-5.DC Input Voltage and Current With 13.2V DC Input to Power AMP FIRST IF - 10.695 MHz SECOND IF - 455 KHz FIRST LOCAL OSCILLATOR- 10.965 MHz Below RECEIVING FREQUENCY SECOND LOCAL OSCILLATOR- 10.240 MHz 2-6.RECEIVER IF AND LOCAL OSCILL

16、ATOR FREQUENCIES. ission : AM(A3E) , FM(F3E) 2-3. SEMICONDUCTORS AND FUNCTION REF.NO * MANUFACTURER INFORMATION * * K.E.C - KOREA ELECTRONICS SEMICONDUCTOR CO.,LTD. * TOSHIBA - TOSHIBA SEMICONDUCTOR CO.,LTD. * SANYO - JAPAN SANYO SEMICONDUCTOR CO.,LTD. * SGS - SGS THOMSON SEMICONDUCTOR CO.,LTD. DESC

17、RIPTIONRXTXREMARK QR1 QR2 QR3 QR4 QR5 QR6 QR7 QQ1 QQ2 QQ4 QAS1 QAS2 QAS3 QAS4 QFS1 QFS2 QUS1 QRS1 QTS1 QG1 QG2 QG3 QG4 QG5 QHL1 QV1 QW1 QW2 QN1 QN2 QT2 QT3 QT4 Q1 Q2 Q3 IC1 IC2 IC3 IC4 IC5 IC6 IC7 KTC4080E KTC4080E KTC4080E KTC4075E KTC4080E KTC4080E KRA2014E KRC410E KTC4075E KRC402E KRC410E KRA305E

18、 KRC402E KRC410E KRC402E KRC410E KRC404E KTC4075E KTA2014E KTA1658 KTA2014E KRC401E KTC3875S KTC3875S KRC402E KTC4080E KTC4080E KTC4080E KRC401E KRA305E KTC4080 2SC2314 2SC2078 KRA226S KRC401E KRC404E DBL5019 KIA358F TDA2003 24WCO2J TMP86FM29UG LC7152 KIA358F RF AMP 1st MIXER 1st MIXER RF ATTENUATOR

19、 IF AMP IF AMP A.N.L. SQ MUTE RF ARRENUATOR AUTO SQ S/W FM MUTE AM B+ AM B+ CONTROL X X POP MUTE SQ CONTROL RX B+ X X X X MAIN REGULATOR CPU REGULATOR X VCO X X X X X X X LCD BACK LIT LCD BACK LIT CPU RESET FM 1F SQ CONTROL X EEPROM CPU PLL X X X X RF ATTENUATOR X X X X RF ATTENUATOR X X X X AM AUDI

20、O PATH FM AUDIO S/W X X X TX B+ TX POWER REGULATOR TX POWER REGULATOR TX POWER REGULATOR MAIN REGULATOR CPU REGULATOR POWER HI/LOW S/W VCO BUFFER DOUBLER TX ENABLE TX ENABLE B+ BUFFER DRIVER POWER AMP LCD BACK LIT LCD BACK LIT CPU RESET X X TX AM AUDIO AMP EEPROM CPU PLL TX FM AUDIO AMP KEC KEC KEC

21、KEC KEC KEC KEC KEC KEC KEC KEC KEC KEC KEC KEC KEC KEC KEC KEC KEC KEC KEC KEC KEC KEC KEC KEC KEC KEC KEC KEC SANYO SANYO KEC KEC KEC AUK KEC SGS HOLTEK TOSHIBA SANYO KEC 4. Description of Frequency Determining and Stabilizing Circuitry 4-1. Introduction The Frequencies for transmitter and receive

22、r first local frequencies are all derived from a signal 10.695MHz cry Phase lcoked loop. stal and second local frequencies are derived from 10.240 MHz crystal by means of a The first local oscillator frequencies are 16.270MHz(CH1) to 16.710MHz(CH40). The second local frequency is fixed at 10.240MHz

23、to generate second IF 455KHz. Transmit, the VCO of the PLL operates 13.4825MHz(CH1) to 13.7025MHz(40CH). The VCO frequency goes to the doublers circuit DW2, LT1, LT2 which doubles the frequency to generate 26.965MHz(CH1) to 27.405MHz(40CH). QV1 VCO QW1 Doublers 13.4825MHz(CH1) 13.7025MHz(CH40) 26.96

24、5MHz(CH1) 27.405MHz(CH40) To transmitter The VCO operating frequency for the receiver is 16.27MHz(CH1) to 16.710MHz(CH40) as the first local oscillator, injected through the buffer amplifier Q302 into the first FET balanced mixer QR2,3. 4-2. Basic Synthesis Scheme The crystal frequency(10.24MHz) is

25、divided by 4069times to make 2.5KHz which is fed to one side of the phase detector. The VCO output is divided by a programmable divider, and fed to other side of the phase detector Pin 22, 23 of IC6. The feedback loop is closed by passing the phase detector output through an active low pass filter a

26、nd using the output to control the VCO frequency through varicap diode DV1,2. Under locked conditions, both of phase detector input signal must be identical at 2.5KHz. The VCO frequency is then given by ; Receiver : Fvco / N = 0.0025 MHz OR Fvco = 0.0025 X N MHz Since “N” is an integer, the VCO freq

27、uency can be stepped up with 2.5 KHz increments. By suitable choice of “N” the desired output frequency can be obtained. Channel 1 Channel 40 N Fvco N Fvco Transmit 5393 3254 13.4825 16.2700 5481 3342 13.7025 16.7100Receiver See the Table 1for other Channels The VCO frequency goes to the doublers ci

28、rcuit, with doubles the incoming signals. VCO Output Frequency Doublers Output Frequency Transmit - - - Transmit CH 1 , 13.4825 MHz CH 40 , 13.7025 MHz 26.965 MHz 27.405 MHz Since all frequencies are obtained from the crystal controlled PLL oscillator, all outputs are coherent with the crystal oscil

29、lator frequency and matching the same percentage accuracy. Program Data & FrequencyTable 1 RX TX Channel Frequency MHz N Fvco N Fvco 1 26.965 3254 16.27 5393 13.4825 2 26.975 3256 16.28 5395 13.4875 3 26.985 3258 16.29 5397 13.4925 4 27.005 3262 16.31 5401 13.5025 5 27.015 3264 16.32 5403 13.5075 6

30、27.025 3266 16.33 5405 13.5125 7 27.035 3268 16.34 5407 13.5175 8 27.055 3272 16.36 5411 13.5275 9 27.065 3274 16.37 5413 13.5325 10 27.075 3276 16.38 5415 13.5375 11 27.085 3278 16.39 5417 13.5425 12 27.105 3282 16.41 5421 13.5525 13 27.115 3284 16.42 5423 13.5575 14 27.125 3286 16.43 5425 13.5625

31、15 27.135 3288 16.44 5427 13.5675 16 27.155 3292 16.46 5431 13.5775 17 27.165 3294 16.47 5433 13.5825 18 27.175 3296 16.48 5435 13.5875 19 27.185 3298 16.49 5437 13.5925 20 27.205 3302 16.51 5441 13.6025 21 27.215 3304 16.52 5443 13.6075 22 27.225 3306 16.53 5445 13.6125 23 27.255 3312 16.56 5451 13

32、.6275 24 27.235 3308 16.54 5447 13.6175 25 27.245 3310 16.55 5449 13.6225 26 27.265 3314 16.57 5453 13.6325 27 27.275 3316 16.58 5455 13.6375 28 27.285 3318 16.59 5457 13.6425 29 27.295 3320 16.60 5459 13.6475 30 27.305 3322 16.61 5461 13.6525 31 27.315 3324 16.62 5463 13.6575 32 27.325 3326 16.63 5

33、465 13.6625 33 27.335 3328 16.64 5467 13.6675 34 27.345 3330 16.65 5469 13.6725 35 27.355 3332 16.66 5471 13.6775 36 27.365 3334 16.67 5473 13.6825 37 27.375 3336 16.68 5475 13.6875 38 27.385 3338 16.69 5477 13.6925 39 27.395 3340 16.70 5479 13.6975 40 27.405 3342 16.71 5481 13.7025 4-3-1. Introduct

34、ion The synthesizer is implemented with the following companents : IC6 is a CMOS LSI that includes most of PLL block. The VCO with varicap diode DV1,2 as a part of the oscillator tank circuit. QV2 is a switching transistor to connect or disconnect the tunning capacitor in the VCO oscillator tank cir

35、cuit for transmitter or receiver. The crystal, X2(10.24MHz) and other components at PIN 1 and 24 of IC6 can make a reference frequency oscillator with internal amplifier. The oscillator output is internally fed to a divied by 4096 to produce A 2.5KHz swuare wave witch is the reference input to the p

36、hase detector. QV1 is connected as a hartley type oscillator with varicap diode as part of the tank circuit. With Appropriate control voltage on D601 the VCO can be oscillate over the required range of 13.4825MHz to 16.710 MHz. 4-3. Description Of Each Block 4-3-2. Reference frequency PLL IC (IC6) X

37、-TAL(X2) VARICAP DIODE(DV1,2) 4-3-3. VCO The programmable inputs for each channel are set by the PLL clock(PIN34), DATA(PIN35), Enable(PIN33) of IC5. Each input signal to control the PLL IC is done with the provided key input PIN 1215. For each key input, an internal code convert EEPROM provides the

38、 appropriate control to the programmable divider for that channel. Since the change transmit and receive, and additional BIT is required ar PIN 16 of IC5 to allow the ROM to recognize the status TX or RX. During transmit the push to talk switch grounds PIN 16 thru diode(DS1) which is the transmit st

39、atus. Thr programmable divider output is fed to the phase detector for comparison with the 2.5KHz reference. See TABLE 1 for actual input and divide ratio on all channels. The phase detector is a digital phase comparator which compares the phase of the reference woth programmable divider output squa

40、re waves and develops a series of pulses whose DC level depends on the phase error of each signal. The phase detector pulse output is fed to an active low pass filter and RC LPF ouput signal of IC6 is filtered and fed to varicap DV1,2 control the VCO frequency. 4-3-4. Programmable divider and its co

41、ntrol 4-3-5. Phase Detector and VCO control 4-3-6. Transmitter / Receiver Buffer AMP The VCO output is fed into buffer AMP QW1 from the capacitor of CW1. 4-3-7. Transmitter Doubler The output signal of QW1 goes to an amplifier tuning circuit(27MHz) QW2, LT1, LT2 which doubles incoming 13MHz signals.

42、 4-3-8. Switching of tuning capacitor in VCO. The VCO circuit must turn with a wide range of frequencies 13.4825MHz - 13.7025 MHz for transmitter and 16.27MHz - 16.710 MHz for receiver. The use of one tuning capacitor in common has adverse effects as a decrease in C in the tuning circuit and the occ

43、urrence of may spurious. To eliminate these effects, the tuning capacitance is switched for transmission or reception. The tank circuit consist of the primary of LV1, CV1, CV4, CV6, CV7 when receiving QV2 becomes off. So. the primary of LV1 and make tuning function. when transmitting, QW2 becomes on

44、. So, the primary if LV1 and the parable capacitance of CV11 make turning function. 4-3-9. Receiver Local Oscillator Outputs 4-4.Frequency Stability -First Mixer : The output of VCO is injected through buffer AMP QW1 and than The emitter follower output through the emitter of 1st mixer or 2,3. -Seco

45、nd Mixer : The output of 10.240 MHz oscillator circuit with X2 is injected into the if IC of IC1. Incoming if signal and 10.240 MHz signal are mixed inside the IF IC to 2nd IF signal 455MHz. FM audio signal are recovered with the way of quadrature detector. AM signlas are recovered with envelope det

46、ector. LET : Fo=Crystal Oscillator Frequency 4-5.Description of other circuits. 4-5-1. Transmitter 1. RF Amplification THEN : Fvco= N X Fr = N(Fo/1800) From which it can be seen, the percentage error in Ft is the percentage error in Fo. The stability of the crystal oscillator is determined primarily

47、 by the crystal itself and having lesser deviation by the active and passive components of the oscillator. The choice of crystal and components is such that the required frequency stability is maintained over the required voltage and tempertature range. Fr=Phase detector reference frequency Fvco=VCO

48、 frequency Ft=Transmit freqency THEN : Fr=Fo/1800 And under locked confitions : Fr =Fvco / N Where N is the programmable divider divide ratio. The output of doubler AMP QW2 is fed through double tuning(27MHz) LT1 and LT2 to the base of PRE AMP QT2. The output is then supplied through tuning circuit LT3 to RF driver AMP QT3. The QT3 output is capacitance divided by tuning c