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Motorola Cm Radio Vhf2 Information Manual

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    							Commercial SeriesCM Radios
    VHF2 (146-174MHz)
    Service Information
    Issu e:  December  2 003 
    						
    							ii
    Computer Software Copyrights
    The Motorola products described in this manual may include copyrighted Motorola computer programs stored 
    in semiconductor memories or other media. Laws in the United States and other countries preserve for 
    Motorola certain exclusive rights for copyrighted computer programs, including the exclusive right to copy or 
    reproduce in any form, the copyrighted computer program. Accordingly, any copyrighted Motorola computer 
    programs contained in the Motorola products described in this manual may not be copied or reproduced in 
    any manner without the express written permission of Motorola. Furthermore, the purchase of Motorola 
    products shall not be deemed to grant, either directly or by implication, estoppel or otherwise, any license 
    under the copyrights, patents or patent applications of Motorola, except for the normal non-exclusive royalty-
    free license to use that arises by operation of law in the sale of a product. 
    						
    							iii
    Table of Contents
    Chapter 1 MODEL CHART AND TECHNICAL SPECIFICATIONS
    1.0 CM140/CM340/CM160/CM360 Model Chart ....................................................... 1-1
    2.0 Technical Specifications ...................................................................................... 1-2
    Chapter 2 THEORY OF OPERATION
    1.0 Introduction .......................................................................................................... 2-1
    2.0 VHF (146-174MHz)  Receiver.............................................................................. 2-1
    2.1 Receiver Front-End  ....................................................................................... 2-1
    2.2 Receiver Back-End ......................................................................................... 2-2
    3.0 VHF (146-174MHz) Transmitter Power Amplifier
     ............................................... 2-2
    3.1 First Power Controller Stage........................................................................... 2-2
    3.2 Power Controlled Driver Stage ....................................................................... 2-3
    3.3 Final Stage...................................................................................................... 2-3
    3.4 Directional Coupler......................................................................................... 2-3
    3.5 Antenna Switch............................................................................................... 2-3
    3.6 Harmonic Filter ............................................................................................... 2-4
    3.7 Power Control ................................................................................................. 2-4
    4.0 VHF (146-174MHz)  Frequency Synthesis .......................................................... 2-4
    4.1 Reference Oscillator ....................................................................................... 2-4
    4.2 Fractional-N Synthesizer ................................................................................ 2-5
    4.3 Voltage Controlled Oscillator (VCO) ............................................................... 2-6
    4.4 Synthesizer Operation .................................................................................... 2-7
    5.0 Controller Theory of Operation ............................................................................ 2-8
    5.1 Radio Power Distribution ................................................................................ 2-8
    5.2 Protection Devices........................................................................................ 2-10
    5.3 Automatic On/Off .......................................................................................... 2-10
    5.4 Microprocessor Clock Synthesiser ............................................................... 2-11
    5.5 Serial Peripheral Interface (SPI) ................................................................... 2-12
    5.6 SBEP Serial Interface ................................................................................... 2-12
    5.7 General Purpose I/O..................................................................................... 2-12
    5.8 Normal Microprocessor Operation................................................................ 2-13
    5.9 Static Random Access Memory.................................................................... 2-14
    6.0 Control Board Audio and Signalling Circuits ...................................................... 2-14
    6.1 Audio Signalling Filter IC and Compander (ASFIC CMP) ............................ 2-14
    7.0 Transmit Audio Circuits ...................................................................................... 2-15
    7.1 Microphone Input Path ................................................................................. 2-15
    7.2 PTT Sensing and TX Audio Processing ....................................................... 2-16 
    						
    							iv
    8.0 Transmit Signalling Circuits ............................................................................... 2-17
    8.1 Sub-Audio Data (PL/DPL) ............................................................................ 2-17
    8.2 High Speed Data .......................................................................................... 2-18
    8.3 Dual Tone Multiple Frequency (DTMF) Data ............................................... 2-18
    9.0 Receive Audio Circuits....................................................................................... 2-19
    9.1 Squelch Detect ............................................................................................. 2-19
    9.2 Audio Processing and Digital Volume Control.............................................. 2-20
    9.3 Audio Amplification Speaker (+) Speaker (-) ................................................ 2-20
    9.4 Handset Audio .............................................................................................. 2-21
    9.5 Filtered Audio and Flat Audio ....................................................................... 2-21
    10.0 Receive Audio Circuits ..................................................................................... 2-21
    10.1 Sub-Audio Data (PL/DPL) and High Speed Data Decoder .......................... 2-21
    10.2 Alert Tone Circuits ........................................................................................ 2-22
    Chapter 3 TROUBLESHOOTING CHARTS
    1.0 Troubleshooting Flow Chart for Receiver RF (Sheet 1 of 2)................................ 3-2
    1.1 Troubleshooting Flow Chart for Receiver (Sheet 2 of 2) ................................ 3-3
    2.0 Troubleshooting Flow Chart for 25W Transmitter  (Sheet 1 of 3) ........................ 3-4
    2.1 Troubleshooting Flow Chart for 25W Transmitter  (Sheet 2 of 3)................... 3-5
    2.2 Troubleshooting Flow Chart for 25W Transmitter  (Sheet 3 of 3)................... 3-6
    3.0 Troubleshooting Flow Chart for Synthesizer ....................................................... 3-7
    4.0 Troubleshooting Flow Chart for VCO ................................................................... 3-8
    5.0 Troubleshooting Flow Chart for DC Supply (Sheet 1 of 2) .................................. 3-9
    5.1 Troubleshooting Flow Chart for DC Supply (Sheet 2 of 2) ........................... 3-10
    Chapter 4  VHF PCB/SCHEMATICS/PARTS LISTS
    1.0 Allocation of Schematics and Circuit Boards ....................................................... 4-1
    1.1 VHF2 and Controller Circuits.......................................................................... 4-1
    2.0 VHF2 1-25W PCB 8488977U01 (Rev. C) / Schematics ...................................... 4-3
    2.1 VHF2 1-25W PCB 8488977U01 (Rev. C) Parts List .................................... 4-19 
    						
    							Chapter 1
    MODEL CHART AND TECHNICAL SPECIFICATIONS
    1.0 CM140/CM340/CM160/CM360 Model Chart
    CM Series VHF2 146-174MHz
    Model Description
    MDM50KNC9AA2_NCM140 146-174 MHz 1-25W 8-Ch
    MDM50KNC9AN2_N CM340 146-174 MHz 1-25W 10-Ch
    MDM50KNF9AA2_NCM160 146-174 MHz 1-25W 64-Ch
    MDM50KNF9AN2_N CM360 146-174 MHz 1-25W 100-Ch 
    Item Description
    X FUD1183_ S. Tanapa VHF2 25W 8 Ch BNC
    XPMUD1879_S. Tanapa VHF2 25W 10 Ch BNC
    X PMUD1874_ S. Tanapa VHF2 25W 64 Ch BNC
    XPMUD1881_S. Tanapa VHF2 25W 100 Ch BNC
    X X FCN6288_ Control Head
    XXFCN5523_Control Head
    XXXX HKN4137_ Battery Power Cable
    X
    X
    X
    X
    RMN50188_
    HMN3596_Mag One Microphone
    Compact Microphone
    XXXX GLN7324_ Low Profile Trunnion
    XXXX6866546D02_RTTE Leaflet
    XXXX 6866537D37_ Safety Leaflet
    XFLD1934ASServicing Kit CM140
    X PMUD1889AS Servicing Kit CM340
    XPMUD1883ASServicing Kit CM160
    X PMUD1891AS Servicing Kit CM360
    X = Indicates one of each is required 
    						
    							1-2 MODEL CHART AND TECHNICAL SPECIFICATIONS
    2.0 Technical Specifications
    Data is specified for +25°C unless otherwise stated.
    General
    Specification VHF2
    Frequency Range:146-174 MHz
    Frequency Stability
    (-30°C to +60°C, 25°C Ref.)±2 PPM
    Channel Capacity:CM140 - 8
    CM340 - 10
    CM160 - 64
    CM360 - 100
    Channel Spacing: 12.5/20/25 kHz
    Power Output:1-25W
    Power Supply: 13.2Vdc (10.8 - 15.6 Vdc) negative vehicle ground
    Dimensions  (L X W X H)118mm X 169mm X 44mm 
    Weight:
       Low power (1-25W) 1.02 Kg 
    Operating Temperature-30 to 60 o C
    Storage temperature -40 to 80
    o C
    Shock and VibrationMeets MIL-STD 810-C,D&E and TIA/EIA 603
    Dust Meets MIL-STD 810-C,D&E and TIA/EIA 603
    HumidityMeets MIL-STD 810-C,D&E and TIA/EIA 603 
    						
    							Technical Specifications1-3
    *Availability subject to the laws and regulations of individual countries.Tr a n s m i t t e r
    Specification VHF2
    Frequency Stability: +/- 2.5ppm
    Modulation Limiting:±2.5 kHz @ 12.5 kHz
    ±4.0 kHz @ 20 kHz
    ±5.0 kHz @ 20/25 kHz
    Current Drain Transmit: 7A (25W)
    FM Hum and Noise:-40 [email protected] kHz
    -45 dB@ 20/25 kHz
    Conducted/Radiated 
    Emissions:-36 dBm < 1 GHz 
    -30 dBm > 1 GHz
    Adjacent Channel Power-60dB @12.5,
    -70dB @ 20/25kHz
    Audio Response:
    ( 300 to 3000Hz)+1, -3dB
    Audio Distortion:
    @ 1000 Hz, 60%
    Rated Maximum Deviation:3% Typical
    Receiver
    Specification VHF2
    Sensitivity (12dBSINAD): (ETS) 0.35µV (12.5kHz) 0.30µV (25kHz) Typical
    Intermodulation : (ETS)>65dB
    Adjacent Channel 
    Selectivity: (ETS)75 dB @ 25 kHz 
    65 dB @ 12.5 kHz
    Spurious Rejection: (ETS)75 dB
    Rated Audio: (ETS) (Extended audio with 4 Ohm 
    speaker)4W Internal , 13W External
    Audio Distortion @ Rated Audio:3% Typical
    Hum and Noise: -40 dB @ 12.5 kHz
    -45 dB @ 20/25 kHz
    Audio Response:
    ( 300 to 3000Hz)+1, -3dB
    Conducted Spurious 
    Emission per FCC Part 15:-57 dBm 1 GHz 
    						
    							1-4 MODEL CHART AND TECHNICAL SPECIFICATIONS 
    						
    							Chapter 2
    THEORY OF OPERATION
    1.0 Introduction
    This Chapter provides a detailed theory of operation for the VHF circuits in the radio. Details of the 
    theory of operation and trouble shooting for the the associated Controller circuits are included in this 
    Section of the manual.
    2.0 VHF (146-174MHz) Receiver
    2.1 Receiver Front-End
    The received signal is applied to the radio’s antenna input connector and routed through the 
    harmonic filter and antenna switch. The insertion loss of the harmonic filter/antenna switch is less 
    than 1 dB. The signal is routed to the first filter (4-pole), which has an insertion loss of 2 dB typically. 
    The output of the filter is matched to the base of the LNA (Q303) that provides a 16 dB gain and a 
    noise figure of better than 2 dB. Current source Q301 is used to maintain the collector current of 
    Q303. Diode CR301 protects Q303 by clamping excessive input signals. Q303 output is applied to 
    the second filter (3-pole) which has an insertion loss of 1.5 dB. In Distance mode, Q304 turns on and 
    causes D305 to conduct, thus bypassing C322 and R337. In Local mode, the signal is routed 
    through C322 and R337, thus inserting 7 dB attenuation. Since the attenuator is located after the RF 
    amplifier, the receiver sensitivity is reduced only by 6 dB, while the overall third order input intercept 
    is raised. 
    The first mixer is a passive, double-balanced type, consisting of T300, T301 and U302. This mixer 
    provides all of the necessary rejection of the half-IF spurious response. High-side injection at +15 
    dBm is delivered to the first mixer. The mixer output is then connected to a duplex network which 
    matches its output to the XTAL filter input (FL300) at the IF frequency of 44.85 MHz. The duplex 
    network terminates into a 50 ohm resistor (R340) at all other frequencies.
    Figure 2-1VHF Receiver Block Diagram
    Mixer
    Xtal Filter
    Controller Front Filter Antenna
    First LO
    2nd LO Xtal Osc25kHzFilter
     IF AmpSecond Filter4- Pole
    25kHzFilter 12.5kHzFilter
    Phase Shift 
    Element IFIC LNA 
    						
    							2-2THEORY OF OPERATION
    2.2 Receiver Back End
    The IF signal from the crystal filter enters the IF amplifier which provides 20 dB of gain and feeds 
    the IF IC at pin 1. The first IF signal at 44.85 MHz mixes with the second local oscillator (LO) at 
    44.395 MHz to produce the second IF at 455 kHz. The second LO uses the external crystal Y301. 
    The second IF signal is amplified and filtered by two external ceramic filters (FL303/FL302 for 
    12.5KHz channel spacing and FL304/FL301 for 25KHz channel spacing). The IF IC demodulates 
    the signal by means of a quadrature detector and feeds the detected audio (via pin 7) to the audio 
    processing circuits. At IF IC pin 5, an RSSI signal is available with a dynamic range of 70 dB.
    3.0 VHF Transmitter Power Amplifier (146-174 MHz)
    The radio’s 25W PA is a three-stage amplifier used to amplify the output from the TX_INJ to the 
    antenna port. All three stages utilize LDMOS technology. The gain of the first stage (U101)and the 
    second stage (Q105) is adjustable and is controlled by pin 7 of U103-2 via U103-3 and U102-1. It is 
    followed by an LDMOS final stage Q100.
    Figure 2-2VHF Transmitter Block Diagram
    Devices U101, Q105 and Q100 are surface mounted. A metal clip ensures good thermal contact 
    between both the driver and final stage, and the chassis.
    3.1 First Power Controller Stage
    The first stage (U101) is a 20dB gain integrated circuit containing two LDMOS FET amplifier stages. 
    It amplifies the RF signal from the VCO (TX_INJ). The output power of stage U101 is controlled by a 
    DC voltage applied to pin 1 from the op-amp U103-3, pin 8. The control voltage simultaneously 
    varies the bias of two FET stages within U101. This biasing point determines the overall gain of 
    U101 and therefore its output drive level to Q105, which in turn controls the output power of the PA.
    Loop
    Pin Diode 
    Antenna 
    Switch
    RF JackAntenna
    Harmonic 
    Filter
    CouplerPA - F i n a lStag e
    From VCO (TX_INJ)
    ControlledStage
    Bias 
    Temperature
    Sense SPI BUSASFIC_CMP
    PA
    PWR
    SET
    PA
    Driver
    Controller
    U103-2Forward  
    						
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