D-STAR

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D-Star stands for Digital Smart Technology for Amateur Radio. D-Star uses the [http://www.jarl.or.jp/English/ JARL protocol.

D-Star allows digital voice and digital data using the technical specs described this (D-Star protocol pdf) documentation.

D-Star purpose is to allow HAM Radio operators to speak further and clearer using digital voice while sending data from 1200 BPS on up at the same time.

D-Star information

D-STAR is an open protocol although it is published by JARL, it is available to be implemented by anyone. While Icom is the only company to date that manufactures D-STAR-compatible radios, any equipment or software that supports the D-STAR protocol will work with a D-STAR system. D-STAR systems can be built using both commercial and homebrew equipment and software. In a D-STAR system, the air link portion of the protocol applies to signals travelling between radios or between a radio and a repeater. D-STAR radios can talk directly to each other without any intermediate equipment or through a repeater using D-STAR voice or data transceivers. The gateway portion of the protocol applies to the digital interface between D-STAR repeaters (see figure 1). D-STAR also specifies how a voice signal is converted to and from streams of digital data, a function called a codec. The D-STAR codec is known as AMBE® (Advanced Multi-Band Excitation) and the voice signal is transmitted in the D-STAR system at 3600 bits/second (3.6 kbit/s). http://www.icomamerica.com/amateur/dstar/dstar2.asp June 15, 2006

D-Star allows you to connect your laptop to your D-Star compliant radio and talk to other D-Star complaint radios with a program like telnet. One of the D-Star compliant radios will need to act as a server for this to work.

Specific D-Star features

"It’s only natural that D-Star’s digital voice capabilities will be linked up with the most popular repeater sharing applications, EchoLink® and IRLP. Since your voice is already digitized within the D-STAR system, third party bridges and converters to and from other digital voice systems an obvious and expected future addition." http://www.icomamerica.com/amateur/dstar/dstar5.asp

D-Star history

D-STAR, a standard published in 2001, is the result of three years of research funded by the Japanese government and administered by the JARL to investigate digital technologies for amateur radio. The research involved Japanese radio manufacturers and other observers. Icom provided the equipment used for development and testing. D-STAR radios and repeaters have been tested extensively and are now ready for public use. http://www.icomamerica.com/amateur/dstar/dstar2.asp June 15, 2006

D-Star technical information

introduction

Digital Voice System’s AMBE-2020™ Vocoder Chip is an extremely flexible, high -performance half-duplex voice compression solution that provides exceptional voice quality at rates as low as 2000 bps. The AMBE-2020™ Vocoder Chip is a low cost, DSP-based voice codec for half-duplex real and non-real time voice compression applications.

The AMBE-2020™ Vocoder Chip implements DVSI’s patented AMBE® Voice Compression Algorithm. The field-proven success of this technology has resulted in its recognition as the standard for voice quality in communication systems around the globe. Satellite systems such as Iridium, ICO, Inmarsat, Thuraya, ACeS, Optus and AMSC/TMI use this technology because of its superior voice quality at low bit rates.

DVSI has packaged this advanced vocoder technology onto a proprietary chip from the world’s leading DSP manufacturer. This single-chip solution achieves a level of performance and reliability typically associated only with customized ASICs but without the risks and high-development costs.

DVSI developed the AMBE-2020™ Vocoder Chip to offer the latest AMBE® Voice Compression Technology with no licensing fees, royalties or the engineering expense typically associated with custom DSP software implementation. With small quantity off-the-shelf availability, this DSP provides low-risk cost-effective voice compression.

Quote from: http://www.dvsinc.com/products/a2020.htm on June 14, 2006 9:00PM PST

Voice samples Original After (This is what D-Star may sound like) What does this mean to the end user? D-Star is a voice over data protocol being targeted for Amateur radio service - the idea being to digitize the voice, vocode it to a low data rate signal, then transmit that over 2 meter FM to a second radio, where it is decoded and played back. The supposed advantages of this are: Longer range - the voice signal does not degrade as it does with narrowband FM as the signal gets weaker. Narrower bandwidth - the D-Star modulation fits within a 12.5 kHz channel spacing. Simultaneous voice and data - the system has a 1200 bps data channel in addition to the voice signal. High data rate (128kBit/sec) on the 1.2GHz band. No distortion of the voice as it goes over a repeater - you don't get the "cascaded c-weight filters" you can get in some repeater systems. http://technocrat.net/d/2006/4/5/2084 wowbagger Wed, 05 Apr 2006 09:35:13 PDT Taken at July 14, 2006 at 9:12PM from we6jbo.