Yet another step closer to HD Radio
Sep 1, 2005 12:00 PM, Chriss Scherer, editor
The window to submit reply comments on NRSC-5 has closed, and with it came a chance for me to sit down to read many of the filings. The replies covered many topics, including some items that were not part of the original FCC request for comments on the NRSC-5 standard. With my relevance filter in place, I sorted through the pieces.
It's not surprising that the reply comments were clearly divided between full support and total opposition. It's refreshing to know that the topic of digital radio itself is so digital. While the positive comments present their own merits about NRSC-5, the negative comments present the more interesting � and sometimes entertaining � perspectives.
NRSC-5 does not specify a codec for the IBOC system. This is because the codec used in the Ibiquity system is covered under patents. Many comments made quick points to identify this as the fatal flaw. While the codec exclusion is not ideal, and the NRSC admitted that, it is not a reason to reject the standard. Codec technology continues to advance. While HDC, the codec used in HD Radio, sounds good at the low bit-rates for which it was designed, I'll take the sure bet that a better codec will be developed before any hybrid operation transition phase is complete. A good example is that Eureka-147 is locked to Layer II, and most people agree that subsequent codecs are better. It is early enough in the IBOC transition that this can be defined later. I said this in my Viewpoint in the July issue.
There were many comments about AM interference for IBOC at night. In addition, some commented on general interference to second-adjacent channels at all times on both bands. It's no secret that there are some challenges to overcome with AM IBOC at night. NRSC-5 doesn't say that the existing system is perfect; it sets the foundation for the system to be a defined standard for the FCC.
Some of the points made relating to interference cite the threat to homeland security. I'm all for being safe, but this is pushing it. If AM radio is the sole connection to public safety in a crisis, we have a bigger problem to solve.
One commenter, David Hershberger, called NRSC-5 archaic. Hershberger says that NRSC-5 approaches the problem from the wrong angle. Instead of defining the transmission standard, the FCC should define a receiver standard. He also suggests that the receiver should not be defined with hardware, but with software. The idea of defining the receiver to be software-defined holds promise.
Compare this concept to the media player on your PC. It can play any kind of file. When it encounters a file encoded with a format it does not know, it finds the codec, installs it and plays the file. Consumer radios can be the same way. We do not yet have the technology available to do this in a simple fashion, but look at one feature of the Radiosophy Multistream receiver. It has a USB port to load software updates into the radio. While it's not practical to plug a car stereo into an Ethernet port, the update could be delivered through a wireless means.
Besides, the radio of the future will not be a dedicated radio. It will be part of a cell phone/PDA/wireless Internet device. For that matter, digital radio will be an IP stream that does not rely on single-channel transmitters.
Several reply comments state that the NRSC is controlled by Ibiquity, large owners and other biased interests. It's true that many participants of the NRSC work for large owners, but their actions are not necessarily dictated by these groups. Besides, the individuals and small companies that complain about the intermingling and conflicts can easily rectify the situation: join the NRSC and participate in the process. It's easy to file comments and complain about the group's actions. But I have said this many times before: if you don't like how something is done, don't complain about; take an active part and change it.
Is NRSC-5 the perfect solution to IBOC? No. There are some parts to be defined yet. It sets a foundation to build upon.
In the meantime, there are other IBOC systems being tested and created, and the door is not closed to them.