DMR and dPMR

dPMR and DMR Overview

dPMR and DMR are two new digital technologies for low cost voice radios. Both technologies have been standardised by ETSI. The DMR system is a two-slot TDMA system offering a range of features and applications (ETSI Standards TS 102 361 and EN 300 113). dPMR is a FDMA system offering lowest cost digital voice solution with the same voice quality as DMR (ETSI Standards TS 102 490 & EN 301 166).

Both standards use 4-FSK modulation variants, DMR using 9600bps in 12.5kHz channels and dPMR 4800bps in 6.25kHz channels. Both use voice digitally coded at 3.6kbit/s.

DMR supports Tier I, Tier II and Tier III operation. Today dPMR is designed as a peer-to-peer solution although ETSI is currently working on a standard for Tier II facilities for dPMR which will be published as document TS 102 658. Both DMR and dPMR can be used in the 446.1MHz license exempt band which has been designated by CEPT ECC (ECC/DEC/(05)12). The nature of dPMR however makes it inherently suitable for very low cost terminal designs, along the lines of the current analogue PMR446 units in the adjacent frequency band (ERC/DEC/(98) 25).

More information on dPMR is available in our article published in Land Mobile magazine in March 2008.

Applied Technology is involved in the development of these technologies and attends the ETSI working group that has developed the standards. In association with our parent company we are also active members of the dPMR MoU group.

Applied Technology can offer a range of product design services including:

• Design of RF solutions compatible with the CMX7141 for dPMR
• RF Demonstrator for the dPMR – ATB010
• Design solutions for DMR radio
• Product design consultancy
• Consultancy on standardisation and inter-operability
• 4FSK Modems based on CMX7031/7041  and CMX7143.

The CMX7141 solution offers a very low cost solution for dPMR and dual mode analogue FM / dPMR designs with excellent performance.

 To find out more contact us at enquires@app-tech.co.uk.

 

RF Demonstrator for dPMR

Applied Technology is pleased announce a demonstrator unit for dPMR technology. The ATB010 PCB is a small, low cost, RF technology demonstrator aimed at speeding manufacturers' design and development of dPMR / PMR446 transceiver products. The board is designed to plug in to the CML Microcircuits DE6181 demonstration kit for the CMX7141 integrated circuit.  Along with a PE0002 host controller, (also available from CML Microcircuits) a full RF transceiver can be assembled with a variety of voice and data options configurable via Function Image™ and control scripts. 

All the necessary RF circuits are provided on the ATB010 PCB: receive and transmitter VCOs, a 500mW RF power amplifier, harmonic filter, antenna switching, LNA, RF to IF mixer and limiter discriminator IF processing. The RF performance is designed to be compliant with EN 301 166 (6.25kHz dPMR) and EN 300 296 (12.5kHz PMR446). The DE6181 demonstration kit is a flexible platform that can provide both digital (dPMR) and analogue (PMR446) functionality. 

The design is production engineered for low bill of materials cost, with a minimum number of component types and values and uses only low-cost off-the-shelf components. The design uses a single 3.6V supply e.g. 3 AAA cells or a Li-ion battery.

Full design information is available for download! – free of charge! To get access all you have to do is register. Information includes: manual, schematics, PCB layout, DE6181/PE0002 scripts, etc. Also available is the product brief including information on how to order ATB010 PCBs.

Typical Results

 All results for 6.25kHz digital mode unless otherwise stated. 

   

dPMR Modulation Spectrum using CMX7141 (DE6181) and ATB010

 

What Can I do with my ATB010?

ATB010 together with a DE6181 + PE0002 and PC controller can be used to demonstrate dPMR / PMR446 technology. The test system is capable of: 

·        Analogue FM (12.5kHz) PMR446 transmission or reception

·        Digital dPMR (6.25kHz) transmission or reception

·        Operation 446.0MHz to 446.2MHz (frequency resolution = 3.125kHz)

·        Send / receive status messages with other dPMR equipment.

·        Make voice calls to dPMR equipment using a RALCWI vocoder.

·        With two ATB010 / DE6181 / PE0002 systems digital mode voice calls can be made using the CMX618 Vocoder IC provided on the DE6181.  

Note: ATB010 itself is a demonstration PCB and has not been approved to any product standards. The user is advised not to radiate signals using the ATB010 without complying with the local regulatory requirements, for example obtaining a test and development licence from the appropriate national body.

  Click here and register for full design information, available for download! – free of charge!

 

Glossary

ATB010                  Demonstration PCB for dPMR radio

4FSK                       Four-Level Frequency Shift Keying

direct mode           Mode of operation where units may communicate outside the control of a network (i.e. mobile to mobile)

CSF                         Configured Services and Facilities

DE6181                  Demonstration PCB for CMX7141 and CMX6x8 Integrated circuits

dPMR                      digital Private Mobile Radio

DMR                        Digital Mobile Radio

ECC/DEC/(05)12  ECC Decision of 28 October 2005 on harmonised frequencies, technical characteristics, exemption from individual licensing and free carriage and use  of digital PMR 446 applications operating in the frequency band 446.1- 446.2 MHz

ERC/DEC/(98) 25 ERC Decision of 23 November 1998 on the harmonised frequency band to be designated for PMR 446

EN 300 113            ETSI Standard covering radio parameters for DMR

EN 301 166            ETSI Standard covering radio parameters for dPMR

IFS                           Initial Services and Facilities

FRS                         Family Radio Service (US licence exempt radio system)

RALCWI                 Robust 2400bit/s Vocoder

TS 102 361            Technical Requirements for Digital Mobile Radio (DMR)

TS 102 490            Peer-to-Peer Digital Private Mobile Radio using FDMA with a channel spacing of 6,25 kHz with e.r.p. of up to 500 mW

 

TS 102 658            dPMR Tier II Standard

PMR446                 License exempt PMR System in the 446MHz band in Europe.