[hpsdr] Is DRM the only free Digital AM waveform?

[kd5nwa]

There is also WinDRM a offshoot of DRM, it's open also, you can send 
voice and digital data at the same time.

At 10:50 PM 4/6/2007, Tony Langdon wrote:
>***** High Performance Software Defined Radio Discussion List *****
>
>At 01:18 PM 4/7/2007, you wrote:
> >***** High Performance Software Defined Radio Discussion List *****
> >
> >
> >A couple of us were discussing receiving and probably even
> >transmitting Digital AM signals with HPSDR or equivalent.  We are
> >looking for a good quality open source/free digital AM protocol that
> >we could implement.  However, the other person mentioned that he
> >wasn't sure if any of the waveforms/protocols were free.  He thought
> >that we'd have to license any that we wanted to use for transmitting.
> >
> >I found the following that appears to be free, however, I'm curious
> >if anyone else in the list has researched this area and/or has any
> >opinion on this topic:
> ><http://en.wikipedia.org/wiki/Digital_Radio_Mondiale>http://en.wiki 
> pedia.org/wiki/Digital_Radio_Mondiale
>
>The DRM encoding is free.  There are now 3 variants that I know of -
>shortwave DRM, standard ham DRM (narrow bandwidth)and DRMDV which is
>a more robust ham version that has just been released.  However, some
>of the CODECs in use on the ham bands, namely MELP (2400bps) and
>MELP-1400bps have IP issues that may make it difficult for us to
>implement (especially since HPSDR would be delivering ready to run
>binary implementations).  It appears that Texas Instruments holds the
>IP rights on these CODECs, looking at the snippets of source I've seen.
>
>I am just getting setup on DRM (ham variant using WinDRM) and DRMDV,
>so will be able to report more as time goes by.  There is also the SW
>broadcasting version, for which there is a free implementation in the
>form of Dream.  The shortwave version uses higher data rates, wider
>bandwidth (9-10 kHz as opposed to 2.5 kHz) and different CODECs to
>the ham variant.  It would be nice to have these modes built into
>HPSDR, this would certainly be an asset - just flip the mode switch
>and away you go - the versatility of SDR.
>
>I look forward to the day when I can take a SDR (without needing the
>PC for processing) out into the field, with all the modes I need, and
>use a PC to update the radio as new modes, filters and other code
>become available.
>
>73 de VK3JED
>http://vkradio.com
>
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Cecil
KD5NWA
www.qrpradio.com www.hpsdr.com

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