Motorola Mth500 Basic 6802963c65 Manual

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MTH500 Portable Radio Basic Service Manual- OVERVIEW
CHAPTER 1
OVERVIEW
To achieve a high spectrum efficiency, the MTH500 uses digital modulation tech-
nology and sophisticated voice-compression algorithm. The voice of the person 
speaking into the microphone is converted into a digital bit stream consisting of 
zeros (0) and ones (1). This stream is then modulated into a radio-frequency (RF) 
signal, which is transmitted over the air to another radio. The process is called dig-
ital modulation.
Digital Modulation Technology
The MTH500 is a portable radio that has two models operating in two different 
frequency ranges: R1: 380-400 MHz and R2: 410-430 MHz. These radios can 
operate in dispatch and phone mode. Also, these radios can operate in TMO 
(Trunked Mode Operation)  and DMO (Direct Mode Operation) modes. It uses 
two digital technologies:  

DQPSK and Time Division Multiple Access 
(TDMA).

 DQPSK is a modulation technique that transmits information by altering the 
phase of the radio frequency (RF) signal. Data is converted into complex symbols, 
which alter the RF signal and transmit the information. When the signal is 
received, the change in phase is converted back into symbols and then into the 
original data.
The system can accommodate 4-voice channels in the standard 25 kHz channel as 
used in the two-way radio.
Time Division Multiple Access (TDMA) is used to allocate portions of the RF 
signal by dividing time into four slots, one for each unit.
Time allocation enables each unit to transmit its voice information without inter-
ference from other transmitting units. Transmission from a unit or base station is 
accommodated in time-slot lengths of 15 milliseconds and frame lengths of 60 
milliseconds. The TDMA technique requires sophisticated algorithms and a dig-
ital signal processor (DSP) to perform voice compressions/decompressions and 
RF modulation/demodulation. 
						

							OVERVIEW:  Voice Compression Technology
2
Voice Compression Technology
Voice is converted into a digital bit stream by sampling the voice at a high rate 
and converting the samples into numbers, which are represented by bits.
Voice compression reduces the number of bits per second while maintaining the 
voice at an acceptable quality level. The MTH500 uses a coding technique called 
ACELP (Algebraic Code Excited Linear Prediction). The compressed voice-data 
bits modulate the RF signal.
 Description
Transceiver Description
All the radio circuitry is contained in the Digital/RF Board and the keypad board. The Digital/RF board is divided
into the following sections: digital, frequency generating, transmitter, and receiver.
Digital Section Description
The digital section includes the Redcap 2 that consists of the Mcore risk machine and the Digital Signal Processor
(DSP).
The Mcore is the controller of the Digital/RF Board. It controls the operation of the transmitter, receiver, audio,
and synthesizer integrated circuits located in the RF section. It communicates with the keypad and display.
The Digital Signal Processor (DSP) performs modulation and de-modulation functions for the radio. It also per-
forms Forward Error Correction and other correction algorithms for overcoming channel errors and ACELP
speech coding. It carries out linear 16-bit analog to digital conversions, audio filtering, and level amplification for
the microphone audio input and the received audio output.
The power and audio section is based on the GCAP III and includes power supplies, 13-bit CODEC, audio routing,
microphone and ear piece amplifiers. A audio power amplifier is used for the loud speaker. 
						

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MTH500 Portable Radio Basic Service Manual- OVERVIEW
Transmitter Path Description
The transmitter circuitry includes a linear class AB Power Amplifier (PA) for the linear modulation of the
MTH500. It also includes a novel cartesian feedback loop to enhance its transmitter linearity and reduced splat-
tering power into adjacent channels. 
The transmitter path consists of a novel cartesian feedback loop that contains the forward and loop feedback paths.
The forward path includes the low noise ODCT (Offset Direct Conversion Transmitter), Balun, Attenuator, and
Power Amplifier. The loop feedback path includes the directional coupler, attenuator, and LNODCT (Low Noise
Offset Direct Conversion Transmitter) ASIC.
The cartesian Feedback output power passes to the antenna through the Isolator, Antenna Switch, and Harmonic
Filter.
Receiver Path Description
The receiver path includes the Antenna Switch, SAW, LNA, ceramic filter, mixer, Crystal Filter, and WPIC
(World Phone IC). The first IF consists of the Crystal Filter and WPIC ASIC.
Frequency Generating Section Description
The frequency generating section provides description of the following main components: Fractional-N Synthe-
sizer, REF. oscillator, Main VCO, WPIC ASIC Synthesizers, LNODCT ASIC Synthesizer, External Offset and
second LO Synthesizer, DSP PLL, and Host PLL. 
						

							OVERVIEW:  Description
4
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MTH500 Portable Radio Basic Service Manual - TEST SETUP & TESTING
CHAPTER 2
TEST SETUP & TESTING
Any level 3 repairs can deeply affect the performance of 
the MTH500 radio and may cause a new tuning proce-
dure. This tuning procedure can be applied by certain 
authorised Motorola depots where the appropriate 
TEST & TUNE EQUIPMENT is available.The appropri-
ate TEST & TUNE EQUIPMENT is a special automated 
test equipment which is only available at some Motorola 
factories and Motorola repair centers. 
Before Testing
Carry out the following instructions before testing:
•Check that you have a fully charged battery (Not required when using Battery 
Eliminator WALN4097).
•Connect an RF cable to the N-type RF Connector of the IFR
•Connect the other side of the RF cable to the antenna adapter assembly 
(Motorola Part Number FLN9659). Connect the RF cable to the other side of 
the antenna assembly connector.
!!
WARNING 
						

							TEST SETUP & TESTING:  Typical Test Setup
6
Typical Test Setup
Figure 1.  Typical Test Setup
      
IFR 2968
MTH500
Battery
Eliminator
(WALN4097)
Power
Supply Antenna Adapter
Assembly
(FLN9659)
RF CableN-Type RF
Connector
3.8 V 
						

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MTH500 Portable Radio Basic Service Manual - TEST SETUP & TESTING
Test Check List:
The following table summarises the required test setups.
No.Test 
NameTest SetupRadio SetupTest ConditionsLimits
1. Base Sta-
tion Regis-
tration
Traffic             
Channel390.125 MHz
422.0125 MHz 3605
880TETRA 380+OMS for R1
TETRA 410MS for R2
Control            
Channel390.125 MHz
422.0125 MHz3605
880TETRA 380+OMS for R1
TETRA 410MS for R2
Time Slot 3
Country Code 753
Network Code 2361
Base Color 1
Location Area 22
Min Rx Level -110dBm
Max Tx Level 30dBm
Access Param-
eter-53dBm
Mobile Power 30dBm
Burst Type Normal
2. Receiver 
RSSIRF Gen Level -80dBm
3. Transmitter 
Burst Power
RF Gen Level 
Burst Power-90dBm 28-32dBm
Timing Error 
						

							TEST SETUP & TESTING:  Typical Test Setup
8
Receiver Tests
1.  Simulate Base Station (registration) 
2.  RSSI
Transmitter Tests
1. Power Burst (Control Range)
2. Power Profiles
3. Tx Burst Timing Error
4. Vector Error RMS and Peak
5. Tx Frequency Error
Call Processing Tests
1. Talk Back
2. Call to Mobile
1KHz Test 
Signal
Group Mode-50dBm
5. Call 
Processing 
Call to Mo-
bile
Private 4 digit random 
number & “Send”28-32dBm
RF Gen Level 
Burst Power-90dBm 28-32dBm
Timing Error 
						

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MTH500 Portable Radio Basic Service Manual - TEST SETUP & TESTING
Duplex Test
1. Digital Duplex Test (Tx)
 
Measurement Capabilities: 
Bar charts (Tx Power, Freq. Err, Vector Rms.), Spectrum Analyser, Power Ana-
lyser, Vector Analyser, Vector Diagrams
How to Configure the IFR 2968 Setup
Perform the following steps to configure the IFR 2968 with the radio set:
1. Turn ON the IFR.
2. Press “Systems” Mode Key (wait until the digital system is initialised).
3. Press the “Tetra Mobile” soft key.
4. Press the “Setup” soft key and enter the System Parameters Screen.                   
5. Press the “Channel Plan” soft key.
6. Press “Tetra 380+OMS” soft key for R1 or “Tetra 410MS” soft key for R2. 
The “Control Channel” automatically changes to “3600” for R1 or “800” for 
R2; and “Traffic Channel” automatically changes to “3700”for R1 or 900 for 
R2.
7. Press twice the “Traffic Channel” soft key and check that the marker goes to 
Timeslot. Press Data key “3” followed by the “Traffic Channel” soft key, to 
change to Timeslot “3”.
8. Press “Country Code” soft key. Enter “753” and “Country Code” soft key.
9. Press “Network Code” soft key. Thereafter, enter “2361” and press “Network 
Code” soft key. 
10. Press “Base Color” soft key. Thereafter, enter “1” and press “Base Color” soft 
key.
11. Press “More” soft key.
12. Press “Location Area” soft key. Thereafter, enter “22” and press “Location 
Area” soft key. 
						

							TEST SETUP & TESTING:  Typical Test Setup
10
13. Press “Min Rx Level” soft key. Thereafter, enter “-110dBm” and press “Min 
Rx Level” soft key.
14. Press “Max Tx Level” soft key. Thereafter, enter “30dBm” and press “Max 
Tx Level” soft key.
15. Press “Access Parameter” soft key. Thereafter, enter “-53dBm” and press 
“Access Parameter” soft key.
16. Press “Test Mode” soft key. Press “Enable” soft key.
17. Press “Base Service” soft key and “Supported” soft key.
Note: You are entering base services setup.
The displayed values are factory defaults and should not be changed.
Power On Registration: required
Power Off Deregistration: required
Priority Cell: yes
Minimum Mode Service: may be used
Migration: supported
System Wide Services: normal mode
18. Press “More” soft key.
TETRA Voice Services: supported
Circuit Mode Data Service: supported
(Reserved): available
SNDCD Service: available
Air Interface Encryption: not available
Advanced Link: not supported
19. Press the “Return” soft key.
20. Press the “Neighbr Cell” soft key.
21. Verify that the following NEIGHBOUR CELL INFO values are displayed: