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Old December 25th 03, 03:15 PM
AL KA5JGV
 
Posts: n/a
Default DRM Reception Changes

There have been changes to software requirements for DRM reception. Mail
received from DRM states the following:

MORE INFORMATION ABOUT THE CHANGES
These upgrades will be submitted to the standards body ETSI.
The upgrades are mainly related to the audio source coding part of the
standard.
They will increase the audio quality of the DRM system, and will align it
with existing, open, audio codec standards.

Specifically, the DRM system upgrades will:

- Change the SBR implementation to the MPEG-4 format
- Replace the low complexity stereo tool with the parametric stereo tool
- Introduce the combination of HVXC and CELP speech coders with SBR
- Implement the MPEG-4 scalable syntax for the audio source coding

As a consequence of these changes, the new format will no longer
be compatible with the current format. Therefore an upgrade of all
transmitters and receivers in use is currently underway.

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Yesterday, Radio Vlaanderen (Belgium) had a simultaneous transmission on
15.530MHz in DRM mode and on 11.730MHz in standard AM mode. Switching back
and forth between the two clearly showed the advantages of DRM. Absolutely
no static or similar noise (the background is completely silent), no fading,
and the audio quality, especially in music, was something you wanted to
listen to. However DRM does have drops (total audio blackout) and when this
happens it is very difficult to tolerate.

At present the choices of DRM stations are very few but I'm sure more will
come into play with time.

I use a modified Ten-Tec RX-350 receiver for DRM reception. If anyone needs
information for the modification see my website at:

http://home.satx.rr.com/ka5jgv/

Al KA5JGV
San Antonio, Tx.