Something that actually WORKS on AM

[ContinuousWave]

I'm not sure what the sample rate for IBOC/HD-AM encoders are, as that isn't published by Ibquity. That being said, I believe what you're mistaking for sampling rate artifacts, are probably CODEC artifacts. Even more with AM-HD at the lower 40kbps bitrate, the effects of running music or spots that were recorded or transcoded and played as Mp3 or AC3 files, don't sound very good (swishy). I've heard AM-HD stations play .wav file at 44.1 that sounded really good. If WLW or WCBS plays a spot that was encoded as an Mp3 for file size or whatever, it is noticeably more swishy. FM-HD requires a 44.1 encoder input for the best quality, even then the station can limit the audio low pass to 15kHz to conserve bits. The Orban dual analog/digital audio processor for HD stations runs a sample rate of around 512kHz, because of look-ahead limiting of peaks rather than traditional clipping. Clipping audio waveforms doesn't work well with HD encoding, since there is a limited number of bits available to spare because of clipping byproducts.



I've got two HD-capable radios in vehicles, and neither will decode AM stereo. Not sure where you heard that. Since AM stereo has been dead and gone for over 25 years now, I couldn't imagine why any receiver manufacturer would bother.

I have heard some HD decode CQUAM...it is NOT most as stated...

As for AM stereo, Delta still sells an exciter and Motorola still makes and sells the ICs needed for reception..so someone is using them

 

[rbrucecarter5]

I'm not sure what the sample rate for IBOC/HD-AM encoders are, as that isn't published by Ibquity. That being said, I believe what you're mistaking for sampling rate artifacts, are probably CODEC artifacts. Even more with AM-HD at the lower 40kbps bitrate, the effects of running music or spots that were recorded or transcoded and played as Mp3 or AC3 files, don't sound very good (swishy). I've heard AM-HD stations play .wav file at 44.1 that sounded really good. If WLW or WCBS plays a spot that was encoded as an Mp3 for file size or whatever, it is noticeably more swishy. FM-HD requires a 44.1 encoder input for the best quality, even then the station can limit the audio low pass to 15kHz to conserve bits. The Orban dual analog/digital audio processor for HD stations runs a sample rate of around 512kHz, because of look-ahead limiting of peaks rather than traditional clipping. Clipping audio waveforms doesn't work well with HD encoding, since there is a limited number of bits available to spare because of clipping byproducts.



I've got two HD-capable radios in vehicles, and neither will decode AM stereo. Not sure where you heard that. Since AM stereo has been dead and gone for over 25 years now, I couldn't imagine why any receiver manufacturer would bother.

I checked mine on WLS a while back at night:
--- Pioneer car radio - stereo indicator lit, but I didn't hear stereo separation on musical bed. Maybe it wasn't a stereo musical bed. I should try again.
--- Sony component tuner - no stereo indicator.
--- Sangean component tuner - stereo indicator and obvious separation on musical beds.

I am about 1000 miles from WLS. Some some HD radios decode C-Quam, others don't. It probably is a firmware algorithm. WLS was seriously degraded with a lot of interference from Mexican stations. But stereo decoded properly. That is something that never happened at night on HD AM even on nearby HD stations like WOAI. So C-Quam is obviously more robust. Regular mono sounds really good on the HD radios, as expected because of the product detector.

 

[TheRover]

WRR was probably a coverage issue. While they were doing HD, I had trouble as close in as Jacksboro, which is pretty pathetic. But now that they have dropped it, they dominate the frequency in the northern part of Austin. And make no mistake, that also means they penetrate buildings a lot better, too.

The only reason I love HD radio is for the HD-2 offerings, formats you don't hear anywhere else. But they will go away if HD ever catches on with consumers. No doubt for rubbish like Kardashian radio, all hip-hop BUTT songs all the time, or other popular drivel. Hopefully satellite and streaming will still be offering more pleasant selections.

WRR is back to HD broadcasting.... but just one HD channel, and, still no musical piece ID information displayed...

WRR Classical 101.1 FM Dallas / Fort Worth
Broadcasting in all-digital HD Radio

 

[Kelly A]

I checked mine on WLS a while back at night:
--- Pioneer car radio - stereo indicator lit, but I didn't hear stereo separation on musical bed. Maybe it wasn't a stereo musical bed. I should try again.
--- Sony component tuner - no stereo indicator.
--- Sangean component tuner - stereo indicator and obvious separation on musical beds.

I am about 1000 miles from WLS. Some some HD radios decode C-Quam, others don't.

But wait, didn't you say most HD radios receive AM stereo? Yes, I believe you did. Even by your questionable test, one out of three radios may, or probably don't. Yet another flip-flop Bruce? Let's go to the tape:

As for stereo - it has been pointed out that many, if not most HD radios decode C-Quam, which is why it would be a viable alternative for music stations. At the very least, it appears that HD radios have to use product detection for HD AM, which is much superior to envelope detection.

It probably is a firmware algorithm.

Wait, so you actually believe a CQUAM decoder is nothing more than firmware? Really?

 

[tomservo]

Wait, so you actually believe a CQUAM decoder is nothing more than firmware? Really?

Why couldn't it be? There are software defined radios that decode all kinds of formats, so why not C-Quam?

I just wish I could hear WLS occasionally but where I live it's — at best — a choppy mix of WLS and whatever Cuban or Mexican station is co-channel. Usually the Spanish stuff wins out, so I never get to hear stereo on my little Walkman unless it's severely degraded, at which point the C-Quam decoder is putting crap all over the place and giving me a headache.

 

[boombox4]

I did a search on HD radio chips and C-Quam and so far I'm getting a few pages (including Wikipedia) that mention that a chip common in many HD capable radios also decodes C-Quam but it wasn't advertised to do such.... Haven't found any specific chip info, though.

I also found several pages with info on relatively new SiLabs (and other makers) chips that decode FM, AM, HD, RDS, DAB, & DAB+ -- All on one chip (But no mention of C-Quam...).

I don't see why an earlier version of such a chip couldn't also have included AM stereo capability if a newer version can do all that.

My guess is that what Mr. Carter says is true -- there are a lot of HD capable radios out there that also have an AM stereo capability. But that capability wasn't advertised.

 

[Kelly A]

I did a search on HD radio chips and C-Quam and so far I'm getting a few pages (including Wikipedia) that mention that a chip common in many HD capable radios also decodes C-Quam but it wasn't advertised to do such.... Haven't found any specific chip info, though.

I also found several pages with info on relatively new SiLabs (and other makers) chips that decode FM, AM, HD, RDS, DAB, & DAB+ -- All on one chip (But no mention of C-Quam...).

I don't see why an earlier version of such a chip couldn't also have included AM stereo capability if a newer version can do all that.

My guess is that what Mr. Carter says is true -- there are a lot of HD capable radios out there that also have an AM stereo capability. But that capability wasn't advertised.

I can't speak to older mid-80's or 90's vintage, or specialty-DX radios from Sangean and such, but just for grins I E-mailed a couple engineering contacts that I've had past vehicle radio dealings-with at Visteon (Chrysler) and Delphi (Ford), to get clarification on this whole stupid AM stereo equipped radio topic. My contact at Visteon responded that they haven't done anything with CQUAM stereo since 1995-2000, when their premium radios came with AM stereo tuners. He claims that like HD radio, there is indeed a separate tuner chip for each of the receiver types, not just some firmware or software that can be turned on. He did say there is firmware built in which interfaces with the controls of the front panel as it relates to the function of the radio, but that's about it. The European-spec radios are completely different boards which contain circuitry for DRM or EUREKA per EBU R138 recommendations, and are manufactured overseas accordingly.

I'm waiting to hear back from my contact at Delphi.

 

[tomservo]

I was told the radio in most early 2000s Volkswagens like mine was a software defined radio and that it could do the different tuning steps, frequencies and AM stereo depending on how it's configured, but I never got confirmation of that from anyone associated with VW.

 

[rbrucecarter5]

Given the amount of time HD was off, HD is obviously not a priority to them. They probably got very few complaints.

 

[Kelly A]

Got an E-mail from my Delphi contact. He isn't able to tell me exactly how their radios are made, but he did indicate that over the past five years, their radios have moved more to SDR architecture which hasn't included AM stereo demodulation. The most common SDR chip for digital-mode radios, including HD Radio, DAB, DAB+, T-DMB and DRM, come from NXP: http://www.nxp.com/products/automotive/multi_standard_digital_radio/

 

[Wimmmex]

Given the amount of time HD was off, HD is obviously not a priority to them.

HD is not a priority to anyone. It's just an added feature that gives more functionality to your radio. It's not the end of the world.

 

[boombox4]

Got an E-mail from my Delphi contact. He isn't able to tell me exactly how their radios are made, but he did indicate that over the past five years, their radios have moved more to SDR architecture which hasn't included AM stereo demodulation. The most common SDR chip for digital-mode radios, including HD Radio, DAB, DAB+, T-DMB and DRM, come from NXP: http://www.nxp.com/products/automotive/multi_standard_digital_radio/

It's interesting in that one of the two chips featured on that page has AM and FM analog interfaces. It's sort of like a do-it-all radio system.

 

[rbrucecarter5]

HD is not a priority to anyone. It's just an added feature that gives more functionality to your radio. It's not the end of the world.

Making my point. So much for "the stations between the stations". They aren't stations to broadcasters, who don't take them seriously. Since this is about the only advantage of HD, and it is being sacrificed by short sighted station management. HD acceptance would have taken dedication to reliability on the part of broadcasters, that obviously never happened. I put it in the past tense, because it looks like another AM stereo. Nice to have, but consumer apathy killed it. It is a zombie technology surviving by sucking money out of gullible station owners, afraid of being left behind in the supposed digital revolution.

 

[rbrucecarter5]

It's interesting in that one of the two chips featured on that page has AM and FM analog interfaces. It's sort of like a do-it-all radio system.

It doesn't surprise me that the NXP chips don't include it. Soon HD will follow AM stereo into the annals of tech history like the Cue Cat, PC Jr, Microsoft Bob, Apple Newton, etc.

 

[semoochie]

Making my point. So much for "the stations between the stations". They aren't stations to broadcasters, who don't take them seriously. Since this is about the only advantage of HD, and it is being sacrificed by short sighted station management. HD acceptance would have taken dedication to reliability on the part of broadcasters, that obviously never happened. I put it in the past tense, because it looks like another AM stereo. Nice to have, but consumer apathy killed it. It is a zombie technology surviving by sucking money out of gullible station owners, afraid of being left behind in the supposed digital revolution.

It sounds better and is free of interference. That's enough for me. I know it isn't, for the average consumer.

 

[tomservo]

It doesn't surprise me that the NXP chips don't include it. Soon HD will follow AM stereo into the annals of tech history like the Cue Cat, PC Jr, Microsoft Bob, Apple Newton, etc.

Not as long as it can be used to feed translators that operate as mini-stations. I think there are more HD subchannels feeding translators in my state now than AMs feeding translators.

 

[Kelly A]

It doesn't surprise me that the NXP chips don't include it. Soon HD will follow AM stereo into the annals of tech history like the Cue Cat, PC Jr, Microsoft Bob, Apple Newton, etc.

Are you again confusing AM-HD with FM-HD? Because they are different, you know. I suspect FM-HD, or some digital modulation form for FM will be around for a very long time, whether individually as popular as analog FM or not.

 

[boombox4]

SCA survived a long time. I think HD still has a chance.

 

[diymedia]

In my mind the problem was related to lack of substantive marketing that was appealing. Most of the large original station groups that invested in HD/IBOC, were under the impression that promoting HD on the station that carried HD was a good idea. Well, I suppose it was from an expense standpoint, but not in a way that interested consumers. Marketing of HD was cryptic and obtuse, assuming somehow that listeners to their stations would be intrigued, running out to purchase a new aftermarket radio or insist that their new car was equipped with HD reception capability. Clearly that didn't happen. I think that had the original station group investors and Ibquity put together a serious war chest of wide ranging marketing campaign dollars outside of their owned stations, interest in HD may have at least gotten off the ground by now.

Agreed, HD's rollout has multiple dimensions to it. But I think that the overarching desire to control the system, and the conditions under which it was rolled out, also cross at multiple places. I remember when the HD Digital Radio Alliance was first created, and in addition to marketing ("Are You Def Yet?") it was also supposed to coordinate the assignment of FM-HD multicast channels. Right there, you're pretty much killing any drive to innovate or take risks. Concerns over the appearance of collusion were dismissed with a rationale like, "well, HD is so new that there's no competition in this market anyway." So why divvy up a nonexistent pie?

 

[Wimmmex]

But I think that the overarching desire to control the system, and the conditions under which it was rolled out, also cross at multiple places.

Considering how well the "AM Stereo" marketplace approach went...and what a great help to the band "extending AM to 1700" did....it was probably not a bad thought that they wanted to control the system. This is why we don't have competing digital radios in different brands of cars (like we did with the AM stereo systems.)

I remember when the HD Digital Radio Alliance was first created...it was also supposed to coordinate the assignment of FM-HD multicast channels. Right there, you're pretty much killing any drive to innovate or take risks.

Actually the "coordination" helped bring about the best variety of formats to HD without any overlapping. There weren't 3 urbans...or 2 jazz formats...and no oldies, etc. The coordination was a benefit to users because it brought them the best variety of "stations between the stations" possible.

And the coordination actually helped innovation and risk...as broadcasters were more willing to take risks if they knew that the formats were not going to be picked willy-nilly with a lot of repeating formats. Boston decided to try an "Irish format...as well as Contemporary Christian format.