American digital radio a half a##ed system: John Anderson at #CBAA13

[diymedia]

But the key thing, as far as I'm concerned, is that it's a commercial failure. Some would also call it a scientific failure. So why so much time and interest about a flop? Like mounting an investigation into the Edsel.

Yep. So it's a failure. Are broadcasters resigned to failure? Yes, I know: the internet! But broadcasting ≠ the internet in many important ways. So, since "we" still have this spectrum, how about thinking of ways to more effectively utilize it? This does not necessarily mean an alternative digital audio broadcast technology, though it is one of the "options."

 

[TheBigA]

This does not necessarily mean an alternative digital audio broadcast technology, though it is one of the "options."

Look, broadcasters have EVERY REASON to find a way to turn their expensive analog frequencies to digital. You see how excited they got when someone at the FCC suggested giving AM owners FM translators. It was like throwing a huge steak at a lion. It wouldn't surprise me if somewhere deep in the bowels of CBS or Clear Channel there are scientists trying to build a better HD Radio. And they don't need access to patents to know how the iBiquity system works. I'm sure a lot of them had access to the "secrets" before they signed on to the "Alliance."

But as I said when you first asked, all of this is in the hands of either politicians or scientists. Those are the two groups who can affect change. Because whatever the alternate system, it first needs to be invented, and then it needs to be approved. Lots of scientists have already been proposing lots of ways to more effectively use the spectrum, and it's all fallen on deaf ears. Unless you are a pied piper who can somehow magically transform a bunch of self-involved politicians to see beyond their own selfish agendas, it seems like a huge waste of time. The way iBiquity did it was to get ten major broadcasters to agree. I'd suggest even that would be hard to do today unless they have a financial stake in it.

 

[jhardis]

at one point, all the major engineering-executives for the broadcasters backing HD cosigned a letter to the FCC that said, in effect, "he's just wrong."

The thing that people have to keep in mind is that the Comment / Reply Comment process is not an opinion poll. It's an information gathering exercise, so that the regulatory agency can be made aware of things that will lead them to the best decision. It's the strength and the reliability of the information that matters, not the number of times it is said or who it is that might say it.

By its own terms, rule 73.317 states by how much the carrier power must be "attenuated" as you move away from the carrier frequency, into adjacent channels. A reading of the rule that purportedly allows the authorized carrier power to be "amplified" (by 20%) rather than "attenuated" in the adjacent channels is wrong on its face -- as I pointed out both before and after that "Engineering Statement" was filed. So, it matters not how experienced and well known the signatories of the Engineering Statement might have been. An opinion that is not backed by a proper engineering analysis, and which reaches an absurd result, isn't worth very much.

- Jonathan

 

[TheBigA]

The thing that people have to keep in mind is that the Comment / Reply Comment process is not an opinion poll. It's an information gathering exercise, so that the regulatory agency can be made aware of things that will lead them to the best decision.

Assuming they read it. I'm at a point where I think the FCC treats the comment process as an obligation, and then just does whatever they want. In a democracy, everyone has a right to state their opinion. But that doesn't mean anyone else has to listen. That's exactly how the FCC treated the ownership rules dog and pony show they did when Michael Copps was there. They sat in a room, listened to everyone yell about Clear Channel, and then ignored it.

 

[Tom Wells]

The thing that people have to keep in mind is that the Comment / Reply Comment process is not an opinion poll. It's an information gathering exercise, so that the regulatory agency can be made aware of things that will lead them to the best decision. It's the strength and the reliability of the information that matters, not the number of times it is said or who it is that might say it.

By its own terms, rule 73.317 states by how much the carrier power must be "attenuated" as you move away from the carrier frequency, into adjacent channels. A reading of the rule that purportedly allows the authorized carrier power to be "amplified" (by 20%) rather than "attenuated" in the adjacent channels is wrong on its face -- as I pointed out both before and after that "Engineering Statement" was filed. So, it matters not how experienced and well known the signatories of the Engineering Statement might have been. An opinion that is not backed by a proper engineering analysis, and which reaches an absurd result, isn't worth very much.

- Jonathan

This is one good reason why I didn't take the trouble to file objections, but rather dedicate my effort into helping more people, mainly via this forum,
to understand better relationships between RF analog behavior and ( alternatively) digital (DC) square wave behavior.

Trade secrets are not bad necessarily. It is merely excellent and confident marketing of a perceived, trusted, protected product or process.

I have 2 patents which received high regards from developemental (ahem) companies, yet found no success amidst severe economic times.
I'm an inventor, not a marketer, promoter, or salesperson. I can't find fault with either patent rights or trade secret rights.

It is correct that in order to receive a patent, the patent document must >fully< teach every secret of the invention, process, etc such that
anyone trained in the "art" would fully understand and be apply to apply the method, etc.

If it is not apparent that that every aspect such as needed as to fully *teach* the method, etc, the patent application is not supposed to be be acceptable.
"Child" patents can often make it VERY difficult to perceive an entire method, and this is perhaps the most troubling part of a picture such as this.

This also is where the USPTO may be sufering from a lack of fully educated examiners.
I was dismayed by a lack of common sense ability in distinction between AC and DC currents, critical to my patentability.
I did learn that hiring a patent attorney to write a few more claims and argue your case a 3rd time did help quite a bit.
Ibiquity certainly has access to some full time patent-ese type people who could write snowballs around most USPTO agents, based on what
I encountered patentling an elementary DC voltmeter. ( Where's the eye-roll smiley?)

 

[jhardis]

...to understand better relationships between RF analog behavior and ( alternatively) digital (DC) square wave behavior. ...

The IBOC system does not modulate square waves. That's not how it works.

The IBOC signal in the time domain is a complicated mess that's designed to be simple in the frequency domain. In the frequency domain, for the FM system, it looks like 382 to 534 (depending on the operating mode) separate carriers spaced 363.4 Hz apart. These carriers all have the same amplitude, but are phase modulated. Most of the carriers are allowed to have one of four different phases: 45 degrees, 135 degrees, 225 degrees (-135 degrees), or 315 degrees (-45 degrees). This is where the digitization happens. Four different phases correspond to two digital bits per carrier. The receiver interprets the carrier as received to the closest allowed phase. For example, if it receives the carrier at 25 degrees, it interprets it as 45 degrees, and uses those corresponding two bits.

At a rate of 344.5 Hz, that is, every 2.902 ms, the carriers change their phase. This is how the bit stream is communicated.

Now, because the carriers have phases that change over time that means that they will occupy a corresponding bandwidth. The faster they change, the more the bandwidth must be. However, because they change at a rate of only 344.5 Hz, the bandwidth required isn't very much. Indeed, it's somewhat less than 363.4 Hz -- which is why the carriers are spaced 363.4 Hz apart. That's just enough separation to make them distinct and resolvable.

It also means that the whole group of carriers has well defined boundaries in the frequency domain. At 300 Hz on either side, the power spectral density is way down.

By the way, this scheme is called Quadrature Phase Shift Keying (QPSK).

- Jonathan

 

[stewie]

How is HD Radio "doing well in the car?" I rent a lot of cars, and none of them have HD. Most have Sirius.

I rent a lot of cars as well and it's normally one of the first things I check for. 10% of the cars I've rented in the last 6 months have HD radio while 80% had Sirius/XM.

 

[landtuna]

I rent a lot of cars as well and it's normally one of the first things I check for. 10% of the cars I've rented in the last 6 months have HD radio while 80% had Sirius/XM.

I am not an apologist for HD radio not am I necessarily a proponent. As I have stated before, there is one HD2 signal in my market that has content I like and that is why I listen and for no other reason.

The discussion as to the popularity of XM/Sirius vs HD seems to indicate that sat radio has an advantage over HD in rental fleets - and that is probably true. Assuming that most rentals are outside the driver's home market it is also logical to assume he/she would not be as familiar with the rental market as with their home market. Also assume that HD radio is slightly more difficult to tune in an unfamiliar vehicle than is sat radio and you have your answer as to why there are more sat radio installs in rental fleets. Also, it seems that HD radio is incorporated into more high end in-dash entertainment systems than run-of-the-mill audio. Since far fewer high end vehicles make it into rental fleets it is a natural omission.

 

[Tom Wells]

Yes, I understand phase quadrature operation, but can't hope to express it to those without technical experience.
I remember once trying to explain how the old TV chroma 3.58 mhz phase angle made colors in the NTSC system.
Average folks can't seem to understand "phase".

I was less concerned with the FM method than the issues with the AM method, where a similar constellation of carriers
causes the wideband jamming sound consuming 50 khz of bandwidth and effectively degrades the host signal with hiss
and a deliberate loss of upper end audio.

 

[stewie]

The IBOC system does not modulate square waves. That's not how it works.

The IBOC signal in the time domain is a complicated mess that's designed to be simple in the frequency domain. In the frequency domain, for the FM system, it looks like 382 to 534 (depending on the operating mode) separate carriers spaced 363.4 Hz apart. These carriers all have the same amplitude, but are phase modulated. Most of the carriers are allowed to have one of four different phases: 45 degrees, 135 degrees, 225 degrees (-135 degrees), or 315 degrees (-45 degrees). This is where the digitization happens. Four different phases correspond to two digital bits per carrier. The receiver interprets the carrier as received to the closest allowed phase. For example, if it receives the carrier at 25 degrees, it interprets it as 45 degrees, and uses those corresponding two bits.

At a rate of 344.5 Hz, that is, every 2.902 ms, the carriers change their phase. This is how the bit stream is communicated.

Now, because the carriers have phases that change over time that means that they will occupy a corresponding bandwidth. The faster they change, the more the bandwidth must be. However, because they change at a rate of only 344.5 Hz, the bandwidth required isn't very much. Indeed, it's somewhat less than 363.4 Hz -- which is why the carriers are spaced 363.4 Hz apart. That's just enough separation to make them distinct and resolvable.

It also means that the whole group of carriers has well defined boundaries in the frequency domain. At 300 Hz on either side, the power spectral density is way down.

By the way, this scheme is called Quadrature Phase Shift Keying (QPSK).

- Jonathan

My head hurts after reading this.

 

[stewie]

I am not an apologist for HD radio not am I necessarily a proponent. As I have stated before, there is one HD2 signal in my market that has content I like and that is why I listen and for no other reason.

The discussion as to the popularity of XM/Sirius vs HD seems to indicate that sat radio has an advantage over HD in rental fleets - and that is probably true. Assuming that most rentals are outside the driver's home market it is also logical to assume he/she would not be as familiar with the rental market as with their home market. Also assume that HD radio is slightly more difficult to tune in an unfamiliar vehicle than is sat radio and you have your answer as to why there are more sat radio installs in rental fleets. Also, it seems that HD radio is incorporated into more high end in-dash entertainment systems than run-of-the-mill audio. Since far fewer high end vehicles make it into rental fleets it is a natural omission.

That's a very good point about most rentals being out of one's home DMA. It's nice to have the "comforts of home" if you have Sirius/XM in your daily driver. I too like discovering HD'2 whether home or in my travels. I wish broadcasters put as much time and attention into putting out a quality product on their HD2's and 3's. I suspect that vary's by market.

 

[diymedia]

The thing that people have to keep in mind is that the Comment / Reply Comment process is not an opinion poll. It's an information gathering exercise, so that the regulatory agency can be made aware of things that will lead them to the best decision. It's the strength and the reliability of the information that matters, not the number of times it is said or who it is that might say it.

I think TheBigA and Tom have pretty much nailed how the comment process actually works nowadays. It seems to me the FCC was only interested in the economic calculus of IBOC: if those who control the majority of industry revenue think the technology's the way to go—and supplemented by NPR to give it a semblance of "bipartisan" consensus and buy-in from the country's largest non-commercial broadcaster—then the science was pretty much secondary. In fact, I remember NPR writing several times that if the FCC were to reopen discussion of alternatives or do anything to interfere with the transition in any way, that had the potential to negate the money invested in the technology by all who adopted it...and THAT was against the "public interest."

This doesn't mean that I think writing comments or reply-comments is pointless (because it's not), but one does have to temper their expectations of engagement with the FCC through the process. Perhaps in other rulemakings it works differently, but in the case of IBOC it was more like an opinion poll or popularity contest than some rigorous or directed discussion toward a rational end-goal.

 

[jhardis]

I think TheBigA and Tom have pretty much nailed how the comment process actually works nowadays. It seems to me the FCC was only interested in the economic calculus of IBOC: if those who control the majority of industry revenue think the technology's the way to go—and supplemented by NPR to give it a semblance of "bipartisan" consensus and buy-in from the country's largest non-commercial broadcaster—then the science was pretty much secondary.

I had a brief discussion with an acquaintance who had been an FCC Commissioner, albeit years before the adoption of the IBOC standard. He commented that the Commission tends to view the NAB and the CEA as being in opposite camps. So when they agree on something, the Commission tends to view it favorably as well. My spin on this (not his) is that it is not the function of the FCC to save the broadcasting industry from itself.

That said, this has little to do with my remark that you quoted. We were talking about technical points raised in public comment about asymmetric sidebands. As Radio World adroitly pointed out, there was the entire industry on one side, and one lone dissenter on the other. Now, while it's a truism that agency inaction is not an action, it's also nonetheless the case that there's been no action after almost two years -- even though some observers counseled "don’t be surprised if the newly-proposed tweaks get adopted promptly." http://www.commlawblog.com/2011/11/...-set-for-comments-on-proposed-hd-radio-tweak/ I take this as evidence that the public comment process worked as it was intended.

- Jonathan

 

[diymedia]

Yep: on the constitutive decisions (i.e., redefinition of the spectral mask and questions of intellectual property), a spankdown occurred. On the minutae of allowing for asymmetric FM-HD sidebands, although the FCC hasn't officially blanket-authorized it, stations can apply for experimental authorization to do it and many have.

This is what is called "the creation of facts on the ground," and at a later date the FCC can come back and say, "so, we let this happen unofficially for several years and there were no problems, so go ahead and officially do it now." It's the same sort of thing that happened with the FM-HD power increase itself (and may be happening with all-digital AM).

For what it's worth, Mr. Hardis, I think the radio industry owes you both three cheers and an apology for fighting the good fights that you have.

 

[Tom Wells]

Even worse than being "nobody" in the comments process, I expected to be fully discounted for my transgressions of 1991.

I first read the digital radio usa white papers sometime in the late 90s in Livonia MI. A field service rep from anther company had printed out a hard copy for me.
Both AM and FM versions behave exactly as described, and as I read, I could already hear the hiss would sound like on the AM version, and indeed it does.

I could not tell that the FM version described would create flutters in analog decode.
It sounded like a reasonable way to encode data at 100 mhz...
And it works fairly well, unless you're hoping for analog decode in a moving car and there are always lots of low-level jetliners where you live.
Then it spits like a mad cat.