HD method of producing the IBOC signals?

[radiopilot]

I know this is probably a silly question and you radio engineerings guys should be able to quickly point it out... but what method is Ibiquity using to code the signal i.e., is it PFM, PDM, or PCM if it's doing that?

I don't mean how they input the signal on the analog sidebands IBOC, but the coding itself.

Radiopilot

 

[Mike Walker]

Here are a couple of places which may answer your question. I'm not a huge wikipedia fan, but I quickly scanned this, and saw no obvious errors

http://en.wikipedia.org/wiki/HD_Radio

The modulation method is called "COFDM". Here's a pdf file from the BBC which explains

http://www.bbc.co.uk/rd/pubs/papers/pdffiles/ptrev_278-stott.pdf

 

[radiopilot]

Here are a couple of places which may answer your question. I'm not a huge wikipedia fan, but I quickly scanned this, and saw no obvious errors

http://en.wikipedia.org/wiki/HD_Radio

The modulation method is called "COFDM". Here's a pdf file from the BBC which explains

http://www.bbc.co.uk/rd/pubs/papers/pdffiles/ptrev_278-stott.pdf

Actually I found a site and read it... funny but I think you all need to read the end of page 5 and beginning of page 6 on how it says:

"The listener is TRAINED to listen to lessor than CD quality" as they perform hearing tests... so it shows the quality is not CD but something lessor!

http://www.nrscstandards.org/DRB/USADR test data report/Appendixb.pdf

Accoring to this... "typical radio listeners will never listen to IBOC DAB under such pristine lab conditions with studio headsets (what 15hz - 22khz Sony or Koss/Sennheiser headphones not good enough?) and amplifiers (you mean like Marantz, Sansui, Sony, etc. aren't up to par?), 96 kbps AAC will be perceived by typical listeners as "virtually" the same as a CD"

Ha ha.... and YET they posted an Audiophile site of some guy's take on how well the audio coming out of the Sangean HDT-1 tuner... how can that be? It's not CD quality as the Ibiquity and the FCC claim it is on FM....

Sounds to me like false claims by Ibiquity and the FCC and the public needs to submit all sorts of anger at these people!

Radiopilot

 

[Mike Walker]

Dude, I listened to HD for four hours LAST NIGHT at 80 miles (WLYT Charlotte NC), to an HD2 stream...48kbps, and IT SOUNDED FANTASTIC. Then I listened to WDAV Davidson NC (about 60 miles)...with the full 96kbps. I am an audio professional, and doubt seriously I could tell the difference between a cd played directly, and over their HD stream.

When HD sounds different, it's not because of the codec...it's because the station has used too much audio processing (compression/limiting). THAT can squeeze the life out of analog OR digital.

 

[OKCRadioGuy]

True.. FM IBOC ISN'T anywhere close to CD quality. The thing I like about it though is how it handles (or DOESN'T) the high end due to not having to deal with pre-emphisis and HF peak limiting. It is a very glaring difference between analog and "HD", and quite an improvement in my humble opinion.

Once again we're dealing with an in-band technology. It's a wonder the stuff works at all. Don't blame iBiquity. Blame the FCC and the political thieves that run it. The thieves didn't want to give radio another chunk of spectrum to do digital right, so we've got what we got. The thieves want to only SELL spectrum. Let's do the best we can with what we have. HD is here folks. It's time to try to make it work as good as we can regardless of how poor of technology it is. (AM HD is worthless.. why bother)

 

[Mike Walker]

Amen brother. When the FCC ruled out the L band back in the 90s, and MANDATED an in-band, on-channel solution, the die was cast. The technological mountain to be climed was ENORMOUS! That it works at all is a astounding. That it works, AND sounds as good as it does is a miracle. I'd wager a week's pay that 96kbps can pass the cd comparison in double-blind testing nine out of ten times. 48kbps obviously doesn't sound as transparent, but I believe it is STILL better than the vast majority of today's analog fm (which is admittedly a low bar!). Even 48kbps, when used engineered properly, is an improvement for most people, under most circumstances.

 

[PocketRadio]

Let's do the best we can with what we have. HD is here folks. It's time to try to make it work as good as we can regardless of how poor of technology it is. (AM HD is worthless.. why bother)

Yes it is here, but its fate is still up to the marketplace - with little consumer interest, this charade cannot go on forever.

 

[Mike Walker]

Name an FCC standard for broadcasting (not specialized communications, but BROADCASTING) that's EVER gone away (analog tv may be the first...time will tell). Not AM stereo (C-Quam is still THE OFFICIAL STANDARD, and no other method may be used.) Not analog am. The only one that KIND OF comes to mind is the RCA color tv system, but that really never got out of the starting gate.

 

[PocketRadio]

Name an FCC standard for broadcasting (not specialized communications, but BROADCASTING) that's EVER gone away (analog tv may be the first...time will tell). Not AM stereo (C-Quam is still THE OFFICIAL STANDARD, and no other method may be used.) Not analog am. The only one that KIND OF comes to mind is the RCA color tv system, but that really never got out of the starting gate.

Same difference - AM Stereo and FMeXtra both stalled, as will HD Radio. So, HD/IBOC stays on-air, and especially on AM, will just accelerate the demise of terrestrial radio. Good, let the HD Radio Alliance "have their cake and eat it too" ! After talking with the engineers at WTWP (WTOP) for 1/2 hour, they know HD/IBOC is flawed technology that is doomed-from-the-start - they said that "the suits" have ignored their warnings. Kind of amusing - we had a good laugh.

 

[Mike Walker]

AM stereo "stalled" by DIGITAL RADIO! THAT is the only reason there are fewer AM stereo stations than a year ago. It is "stalled" with an installed base of MILLIONS of radios, and new ones ON THE MARKET NOW! Just about all HD radios can tune AM stereo, giving listeners in areas served by analog AM stereo a reason to buy them. That's why WNMB in North Myrtle Beach SC is promoting the radios strictly as AM stereo units.

Again..name a technology that's gone away? A BROADCASTING standard. Tick, tick, tick.

 

[PocketRadio]

AM stereo "stalled" by DIGITAL RADIO! THAT is the only reason there are fewer AM stereo stations than a year ago. It is "stalled" with an installed base of MILLIONS of radios, and new ones ON THE MARKET NOW! Just about all HD radios can tune AM stereo, giving listeners in areas served by analog AM stereo a reason to buy them. That's why WNMB in North Myrtle Beach SC is promoting the radios strictly as AM stereo units.

Again..name a technology that's gone away? A BROADCASTING standard. Tick, tick, tick.

"Broadcast Dialogue"

"That is, if digital radio ever gets off the ground at all. After all, the U.S. isn’t moving very quickly toward its IBOC digital radio system either. Arnish noted that while Canadian broadcasters had already spent huge amounts on transmitters, and digital upgrades, no one is listening. He sees a close parallel to what happened with AM Stereo, which was, more or less, a failure. AM stereo was supposed to be the saviour of AM radio. I think if the manufacturers had got on board, AM radio may still be profitable today,” he said, “But the manufacturers didn’t get on board to start bringing out AM/FM stereo radios. Unless the manufacturing industry is willing to do a similar type of thing where they have FM/Eureka or FM/IBOC, whatever it may be, I don’t think it’s going to happen in Canada,” he said. “We don’t have any listeners talking to us saying, ‘I wish you guys had digital radio’. I just don’t see it being a big deal with listeners at this point in time." Indeed, listeners have a lot more to choose from these days, with the proliferation of iPods, MP3 players, satellite radio and the Internet, and it’s getting harder and harder to wow them with the idea of digital radio."

http://www.broadcastdialogue.com/article_view.asp?action=view&idnumber=667

No one cares about digital radio !

 

[PocketRadio]

AM stereo "stalled" by DIGITAL RADIO! THAT is the only reason there are fewer AM stereo stations than a year ago. It is "stalled" with an installed base of MILLIONS of radios, and new ones ON THE MARKET NOW! Just about all HD radios can tune AM stereo, giving listeners in areas served by analog AM stereo a reason to buy them. That's why WNMB in North Myrtle Beach SC is promoting the radios strictly as AM stereo units.

Again..name a technology that's gone away? A BROADCASTING standard. Tick, tick, tick.

"AM Stereo"

"1982 - After another series of lawsuits and accusations, the FCC decides that the marketplace should decide and revokes the Magnavox certification as the AM stereo standard for political reasons. The marketplace continues fighting it out, and this becomes a death blow to the possibility of AM stereo becoming commonplace across the board."

http://en.wikipedia.org/wiki/AM_stereo

Just as with HD/IBOC, the FCC has left it up to the marketplace to determine the fate of AM Stereo - there is one huge difference, in that AM Stereo does not trash the AM band with adjacent-channel interference, driving listeners away.

 

[Mike Walker]

Great research. Except that's not the whole story. Not even the first chapter. In the early 90s the FCC decided that the marketplace HAD decided, and declared C-Quam THE STANDARD, requiring all other systems to leave the air. In fact, expanded band stations (those above 1600khz) were REQUIRED to be AM STEREO! REQUIRED!

The FCC didn't repeat the "marketplace decision" mistake this time, and is unlikely to again. They CHOSE A STANDARD. In 1982 they REFUSED to choose a standard. This time they didn't refuse, didn't even hesitate. They've acted. That's all she wrote. Not only can't the marketplace decide, it is ILLEGAL to use other systems, and they have said that they will summarily discard ANY application for ANY NEW SYSTEM! So much for your theory that the "marketplace will decide". They are REFUSING to allow other systems to be considered at this point, because THE DECISION HAS BEEN MADE! All that remains is nighttime authority for AMs. For better or worse, that's coming too.

 

[PocketRadio]

AM Stereo and FMeXtra are still allowed - the FCC is just not accepting new technologies. HD Radio is A standard, not THE standard. Nighttime AM-HD will eventually chase listeners away, and will hasten its death.

"The AM STEREO Page"

http://users.hfx.eastlink.ca/~amstereo/amstereo.htm

See, AM Stereo even has its own Web site.

 

[awj223]

Great research. Except that's not the whole story. Not even the first chapter. In the early 90s the FCC decided that the marketplace HAD decided, and declared C-Quam THE STANDARD, requiring all other systems to leave the air. In fact, expanded band stations (those above 1600khz) were REQUIRED to be AM STEREO! REQUIRED!

The FCC didn't repeat the "marketplace decision" mistake this time, and is unlikely to again. They CHOSE A STANDARD. In 1982 they REFUSED to choose a standard. This time they didn't refuse, didn't even hesitate. They've acted. That's all she wrote. Not only can't the marketplace decide, it is ILLEGAL to use other systems, and they have said that they will summarily discard ANY application for ANY NEW SYSTEM! So much for your theory that the "marketplace will decide". They are REFUSING to allow other systems to be considered at this point, because THE DECISION HAS BEEN MADE! All that remains is nighttime authority for AMs. For better or worse, that's coming too.

Wrong. Approving HD was not equivalent to choosing a standard. REQUIRING HD and setting a date for an analog sunset, after which HD must operate in full digital, would have been setting a standard. There is a big difference between required and allowed. All that we have now is an FCC-approved standards war between analog, HD, and any other systems that are allowed to operate like Cam-D and FM eXtra. However unlike most standards wars, one system begins with a 99.9% market share.

I can answer your question about broadcasting standards that have disappeared in a couple more years: NTSC. The reason is that the FCC did choose a TV standard. It has made the same mistake with HD/Cam-D/eXtra that it made with AM stereo however. No standard mandated, no analog sunset, and the same old "the marketplace will decide" talk. You never heard anyone say that the marketplace would decide whether the NTSC to DTV transition happens, did you?

 

[R.F. Burns]

Great research. Except that's not the whole story. Not even the first chapter. In the early 90s the FCC decided that the marketplace HAD decided, and declared C-Quam THE STANDARD, requiring all other systems to leave the air. In fact, expanded band stations (those above 1600khz) were REQUIRED to be AM STEREO! REQUIRED!

The FCC didn't repeat the "marketplace decision" mistake this time, and is unlikely to again. They CHOSE A STANDARD. In 1982 they REFUSED to choose a standard. This time they didn't refuse, didn't even hesitate. They've acted. That's all she wrote. Not only can't the marketplace decide, it is ILLEGAL to use other systems, and they have said that they will summarily discard ANY application for ANY NEW SYSTEM! So much for your theory that the "marketplace will decide". They are REFUSING to allow other systems to be considered at this point, because THE DECISION HAS BEEN MADE! All that remains is nighttime authority for AMs. For better or worse, that's coming too.

Wrong. Approving HD was not equivalent to choosing a standard. REQUIRING HD and setting a date for an analog sunset, after which HD must operate in full digital, would have been setting a standard. There is a big difference between required and allowed. All that we have now is an FCC-approved standards war between analog, HD, and any other systems that are allowed to operate like Cam-D and FM eXtra. However unlike most standards wars, one system begins with a 99.9% market share.

I can answer your question about broadcasting standards that have disappeared in a couple more years: NTSC. The reason is that the FCC did choose a TV standard. It has made the same mistake with HD/Cam-D/eXtra that it made with AM stereo however. No standard mandated, no analog sunset, and the same old "the marketplace will decide" talk. You never heard anyone say that the marketplace would decide whether the NTSC to DTV transition happens, did you?

C'mon, Cam-D is done. Say goodnight. I don't care if it is allowed or not. No one other than a few small operators are using Cam D. There are no receivers and no manufacturer is going to produce radios for this system. FMeXtra has the sme problem. Those systems are not going to exist in a few years. Canada will end up doing what the US does, most likely. It makes sense populationwise. the US is by far the largest consumer of consumer electronics and it won't make sesne for Canada to operate using a different system. As to compatiablility with Europe, the US has never had compatible TV with Europe, and most of the world for that matter. Somehow we survived that for decades. We also use different power standards by the way. Digital Mondial does not work with analog. That is why the US didn't choose that system for digital broadcasting. AM stereo for all intense and puposes is dead, much as the AM stereo crowd wishes it was otherwise. It's gone the way of the old RCA needle in groove video disc. We used to have a handful of AM stereo stations in NYC. Today there are NONE. Am stero generators are being used as doorstops for many stations who still have the old exciters. No one is forcing anyone to turn on a IBOC generator. Of course they could try the Cam_d system on Am but if they want an audience to hear their digital signal it's Iboc, because there are no radios being sold for Cam-D. Talk about wasted electricity.