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Radio revolution: the DRM way
With clear, near-FM quality sound, excellent reception
and dramatic improvement over analogue, Digital Radio Mondiale (DRM) will revitalize radio in markets worldwide. Traditional AM can travel great lengths along the curvature of the earth, but it is notoriously prone to disturbances. The same holds true for short wave, which can reach the other side of the planet by bouncing a signal off the ionosphere. But its reception is prone interference from solar conditions, the time of day and year as well as the distance between the transmitter and the target receiver. There is a global trend towards the adoption of digital technology in radio and communications, especially for distribution and transmission. Digitalization offers many substantial advantages to national/international broadcasters and info casters. We are seeing the introduction of high quality delivery systems in homes. FM sound broadcasting is gradually moving to a DAB standard. But coverage on FM 88-108 MHz (VHF) is limited. For many national and international broadcasters, the advantage of a complementary digital broadcast system below 30 MHz is gradually emerging. However, the limited fidelity of existing AM services is causing listeners to search for other alternatives. Implementation of digital radio in today's AM bands (i.e. long, medium and short wave) will enable operators to provide services that should be successful with both existing and future high-quality services operating on other parts of the dial. Digital broadcasting on short wave, medium wave, or long wave (AM) is highly advantageous when compared to the conventional analogue system that is now in use. Digital Radio Mondiale (DRM) is a fast emerging domain that combines the benefits of FM and AM. This has FM like sound quality with lesser multi-path interference and the reach of AM. Some DRM receivers and equipment are already available to broadcasters and consumers, with more expected throughout 2004. Besides providing near - FM quality audio, the DRM system has the capacity to integrate data and text. This additional content can be displayed on DRM receiver to enhance the listening experience. Unlike digital systems that require a new frequency allocation, DRM uses existing AM broadcast frequency bands. The DRM signal is designed to fit in with the existing AM broadcasting AM broadcast band plan, based on signals of 9 kHz or 10 kHz bandwidth. It has modes requiring as little as 4.5 kHz or 5 kHz bandwidth, plus modes that can take advantage of wider bandwidth, such as 18 or 20 kHz. Simulcast testing is underway. Many existing AM transmitters can be easily modified to carry DRM signals. The DRM technology works by encoding the signal using MPEG 4 compression to make it fit the existing AM bandwidth. While minimizing interface, the digital technology has only two modes: reception and no reception. Hardcore short wave fans who appreciate the challenge of deciphering short wave broadcasts unperturbed by the notorious fading may lament this. But near FM digital quality makes short wave interesting for an audience that has never touched a world band receiver before. Another advantage is that DRM requires only 10% of the power needed for traditional short wave transmission and therefore, for broadcasters, new transmission equipment pays for itself. Furthermore, DRM allows for dual transmission mode, broadcasting analogue as well as digital. DRM applications include fixed and portable radios, car receivers, software receivers and PDAs. Depending on broadcasters preferences, the DRM system can use three types of audio coding. MPEG4 AAC audio coding augmented by SBR bandwidth extension is used as a general-purpose audio coder and provides the highest quality. MPEG4 CELP speech coding is used for high quality speech coding where there is no musical content. HVXC speech coding can be used to provide a very low bit-rate speech coder. Today, DRM is the world's only non-proprietary, digital system for short, medium and long wave with the ability to use existing frequencies and bandwidth across the globe. It is the only digital radio system recommended by the international telecommunication union (ITU) for all the three radio bands below 30MHz short wave, medium wave, and long wave. In January 2003 the DRM consortium took the first hurdle in standardizing audio broadcasts on the AM bands when the International Electro-technical Committee (IEC) granted the DRM transmission technology an international standard. Since DRM's inaugural broadcast on June 16, 2003, more than 60 broadcasters have started transmitting their daily, weekly or periodic DRM programs. Thereafter, an increasing number of broadcasters started their DRM transmissions. In August 2003, DRM and the World DAB Forum announced their cooperation, paving the way for DRM and DAB capable receivers. Sony has committed to help expand the markets for digital radio in Europe, pledging its active support in the commercial sectors of both DRM and World DAB Forum. India remains oblivious to the benefits of such a platform; leave aside launching this technology. While speaking to India's only radio network in this context, few were even aware that radio was on the threshold of going digital! (Recently published in AV MAX, an audio-visual monthly publication via Mukesh Kumar GRDXC) |
#2
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RivaScoot wrote: On 13 Dec 2004 03:16:31 GMT, "Mike Terry" wrote: With clear, near-FM quality sound, excellent reception and dramatic improvement over analogue, Digital Radio Mondiale (DRM) will revitalize radio in markets worldwide. [snip] Well, DRM won't be standard for quite some time. Anyway, I find such digital broadcasts just a wee bit TOO perfect. There's nothing like listening to the snap, crackle and pop of a shortwave signal bouncing from halfway around the world. Digital just makes things TOO easy. RivaScoot I'm not expert, but my understanding is that DRM is an improvement over analogue only under optimal circumstances (i.e., when there's adequate signal strength). If the signal strength dips below a magical threshold, the signal because completely inaudible on DRM--which makes it inferior to analogue in many, if not most, real world listening conditions. Steve |
#3
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On 13 Dec 2004 03:16:31 GMT, "Mike Terry"
wrote: With clear, near-FM quality sound, excellent reception and dramatic improvement over analogue, Digital Radio Mondiale (DRM) will revitalize radio in markets worldwide. Hmm. I guess the US isn't part of "worldwide." Last I heard, IBOC was the mistake of choice in the US. So far as I know only IBOC and Kahn's CAM-D are the only systems in contention here, with CAM-D to roll out soon with several stations on board and receivers coming soon. Are you lumping DRM and IBOC together? Today, DRM is the world's only non-proprietary, digital system for short, medium and long wave with the ability to use existing frequencies and bandwidth across the globe. CAM-D is compatible with all of the above. By "non-proprietary" do you mean to say that the patent holders of DRM are giving it away with no manufacturer's licensing fees? I speak with a lot of stations. Not one has mentioned DRM as something they're considering. Rich |
#4
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I agree, and thus my interest also in amateur astornomy - hunting down
and experiencing the difficult target is a good deal of the fun - but - The people who broadcast don't feel this way. They want to be HEARD, loud and clear. every person who doesn't get all the info they broadcast is waste of their time and money. For the big guys, anyway, DRM may be closer than we like. Bruce Jensen |
#5
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bpnjensen wrote: I agree, and thus my interest also in amateur astornomy - hunting down and experiencing the difficult target is a good deal of the fun - but - The people who broadcast don't feel this way. They want to be HEARD, loud and clear. every person who doesn't get all the info they broadcast is waste of their time and money. For the big guys, anyway, DRM may be closer than we like. Bruce Jensen I don't know about DRM, but IBOC achieves its goals at the expense of the upper and lower adjacent channels. WTMJ Milwaukee, 620kHz, which is located 50 miles away from my location, wipes out both 610 and 630kHz. When I contacted the IBOC folks and advised them about this, they hawked about the benefits of this system. When I asked them how their system would handle the effects of selective fading, they didn't have an answer. When I told them that I had developed MW receiver with Sync detection that would help with these reception problems, and that nobody would have to pay a licensing fee to enjoy those benefits, they didn't have an answer for this one either. I never heard from them again. Pete |
#6
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Rich Wood wrote:
On 13 Dec 2004 03:16:31 GMT, "Mike Terry" wrote: With clear, near-FM quality sound, excellent reception and dramatic improvement over analogue, Digital Radio Mondiale (DRM) will revitalize radio in markets worldwide. Hmm. I guess the US isn't part of "worldwide." Last I heard, IBOC was the mistake of choice in the US. So far as I know only IBOC and Kahn's CAM-D are the only systems in contention here, with CAM-D to roll out soon with several stations on board and receivers coming soon. Are you lumping DRM and IBOC together? No, DRM signals are already audible all over the US. It's not legal to transmit the stuff, but it's certainly legal to receive it, and there is plenty of DRM shortwave stuff coming over the horizon. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#7
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bpnjensen wrote: I agree, and thus my interest also in amateur astornomy - hunting down and experiencing the difficult target is a good deal of the fun - but - The people who broadcast don't feel this way. They want to be HEARD, loud and clear. every person who doesn't get all the info they broadcast is waste of their time and money. For the big guys, anyway, DRM may be closer than we like. Bruce Jensen I really don't believe that DRM will result in larger audiences for the shortwave broadcasters. If the broadcasters think that DRM will lure even one percent of the people listening to mainstream AM and FM over to shortwave, they're living in a dream world. That's just never, ever going to happen. Ten years from now, someone will post to rec.radio.shortwave inquiring about what DRM was. Steve |
#8
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wrote in message ups.com... bpnjensen wrote: I agree, and thus my interest also in amateur astornomy - hunting down and experiencing the difficult target is a good deal of the fun - but - The people who broadcast don't feel this way. They want to be HEARD, loud and clear. every person who doesn't get all the info they broadcast is waste of their time and money. For the big guys, anyway, DRM may be closer than we like. Bruce Jensen I really don't believe that DRM will result in larger audiences for the shortwave broadcasters. If the broadcasters think that DRM will lure even one percent of the people listening to mainstream AM and FM over to shortwave, they're living in a dream world. That's just never, ever going to happen. Ten years from now, someone will post to rec.radio.shortwave inquiring about what DRM was. I figure they'll lose at least 80% of the listeners they already have, because the poor folk in most countries that listen to SW won't be able to afford to upgrade to a DRM radio. |
#9
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Maybe not.
Perhaps what we will see is a 2 tier system. Broadcasts focussed at rich countries will use DRM while broadcasts for poor countries (perhaps the majority) will remain AM. Over time the price of DRm radios should drop allowing more and more people to use DRM. cheers Peter "Brenda Ann" wrote in message ... wrote in message ups.com... bpnjensen wrote: I agree, and thus my interest also in amateur astornomy - hunting down and experiencing the difficult target is a good deal of the fun - but - The people who broadcast don't feel this way. They want to be HEARD, loud and clear. every person who doesn't get all the info they broadcast is waste of their time and money. For the big guys, anyway, DRM may be closer than we like. Bruce Jensen I really don't believe that DRM will result in larger audiences for the shortwave broadcasters. If the broadcasters think that DRM will lure even one percent of the people listening to mainstream AM and FM over to shortwave, they're living in a dream world. That's just never, ever going to happen. Ten years from now, someone will post to rec.radio.shortwave inquiring about what DRM was. I figure they'll lose at least 80% of the listeners they already have, because the poor folk in most countries that listen to SW won't be able to afford to upgrade to a DRM radio. |
#10
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I am a poor folk,,, well,let me put it this way,, not exactly poor but I
think I almost fall in that bracket range or whatever.I am looking for meself a rich old widow woman.If y'all see one,,, send here over to me,Please. cuhulin |
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