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
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