I posted this at rec.audio. I'll crosspost it here, as my response is
still the same:

HD RADIO is no worse than DAB or DRM radio


I hear a LOT of people complaining about Hybrid Digital Radio, but
from what I've heard from European listeners, HDR is no worse than DAB
(poor quality audio;worse than FM), or DRB (both poor quality &
interference w/ existing AM stations).

Thoughts?

Opinions?

Frankly I'm a bit surprised at the reaction. There's currently a
transition from analog to digital broadcasting (both in American and
the European Union), and there will be some growing pains, but it's
only temporary. In the LONG TERM, the digital radio will provide
better sound than the current analog (like upgrading FM Stereo to 300
kbps Surround).

Wouldn't it be cool to have 5.1 surround from your radio?

Or have your FM station suddenly multiply from 1 station to 4
stations (offering, for example, 2000s-era music on the main channel)
(and 90s, 80s, 70s on the 3 sub-channels). Or maybe a Jazz station
dividing itself into Modern Jazz, Mid-Century Jazz, and Classic Big
Band-era Jazz. FM could effectively triple its number of channels.

Well the IDEA is sound, even if the analog-to-digital (HD, DAB, DRM)
transition has some growing pains to overcome.

On Sat, 29 Sep 2007 13:09:45 -0700, SFTV_troy
wrote:

Frankly I'm a bit surprised at the reaction. There's currently a
transition from analog to digital broadcasting (both in American and
the European Union), and there will be some growing pains, but it's
only temporary. In the LONG TERM, the digital radio will provide
better sound than the current analog (like upgrading FM Stereo to 300
kbps Surround).

What is the reason for your optimism? Every other advance in radio has
been better by design, and demonstrated its improvement from day 1.
Digital radio hasn't done that - it has been poor from day one, and to
be better than its predecessor it will need to get a whole heap better
then it is now.

What do you believe will be the basis of that improvement?

d

--
Pearce Consulting
http://www.pearce.uk.com

On Sep 29, 4:22 pm, (Don Pearce) wrote:
On Sat, 29 Sep 2007 13:09:45 -0700, SFTV_troy
wrote:

Frankly I'm a bit surprised at the reaction. There's currently a
transition from analog to digital broadcasting (both in American and
the European Union), and there will be some growing pains, but it's
only temporary. In the LONG TERM, the digital radio will provide
better sound than the current analog (like upgrading FM Stereo to 300
kbps Surround).

What is the reason for your optimism? Every other advance in radio has
been better by design, and demonstrated its improvement from day 1.
Digital radio hasn't done that - it has been poor from day one, and to
be better than its predecessor it will need to get a whole heap better
then it is now.

What do you believe will be the basis of that improvement?

d

--
Pearce Consultinghttp://www.pearce.uk.com

HDradio is worse than DAB insofar as the so-called IBOC implementation
guarantees interference to both the analog main channel and to
adjacent channel stations. DAB has been implemented on exclusive
spectrum, or, at least, spectrum that is not already used for consumer
applications. As to the quality, yes, a DAB multiplex can be exploited
to provide 1990's pioneer streaming audio quality for many program
streams channels or a few streams at 1980's near-CD quality. HDradio
benefits from a decade of codec and silicon development needed for it
to have marginally acceptable quality in a much more restrictive
bandwidth. So, too, does DRM benefit from said development, making it
possible to provide a digital carrier within LW,MW and SW channeling
plans. Thast said, I find it much less fatiguing to listen to a
program on an analog AM carrier than to the same program over DRM.

Adverse reaction to HDradio is stronger than what it probably was to
DAB because of the perceived negative effects on analog reception and
the lack of new program offerings. DAB takeup has succeeded as well as
it has in the UK because of new program services, not because of audio
quality, and because of a concerted government, broadcaster and
manufacturing industry push, the likes of which we have not seen in
other countries. A stronger parallel can be drawn to the sizable
takeup of XMRadio and Sirius satellite services in the US and Canada -
the quality stinks but the program choice and wide ranging coverage
are unique.

DRM is still an open question - my dabbling with it persuaded me that
it is not really viable where sky-wave propagation is involved, either
as the main path or as an interferer to the desired ground-wave path.
That said, it should do as well or better than HDradio for LW, MW,
26MHz, and VHF but is as disruptive to existing analog stations.

I've been more impressed by synchronous AM demodulation of AM signals
than by a digital equivalent. It's a pity we could not get mass
manufacturing of synch AM radios and ultimately convert all AM
stations to USB with reduced carrier for power savings and reduced
interference.

Tom

Tom wrote:

...So, too, does DRM benefit from said development, making it
possible to provide a digital carrier within LW,MW and SW channeling
plans. Thast said, I find it much less fatiguing to listen to a
program on an analog AM carrier than to the same program over DRM.

I've never heard DRM. How does it sound, and why is it "fatiguing" to
hear?



DAB...because of a concerted government, broadcaster and
manufacturing industry push, the likes of which we have not seen in
other countries. A stronger parallel can be drawn to the sizable
takeup of XMRadio and Sirius satellite services in the US and Canada -
the quality stinks but the program choice and wide ranging coverage
are unique.

The quality stinks? Really? I listen to XM streams via the internet,
and they sound just fine. Is there really that huge of a difference
between Internet and Mobile Receiver?



I've been more impressed by synchronous AM demodulation of AM signals
than by a digital equivalent. It's a pity we could not get mass
manufacturing of synch AM radios and ultimately convert all AM
stations to USB with reduced carrier for power savings and reduced
interference.


What's USB? What's synchronous AM demodulation? Thanks.

"SFTV_troy" wrote in message
ups.com...

Tom wrote:

...So, too, does DRM benefit from said development, making it
possible to provide a digital carrier within LW,MW and SW channeling
plans. Thast said, I find it much less fatiguing to listen to a
program on an analog AM carrier than to the same program over DRM.

I've never heard DRM. How does it sound, and why is it "fatiguing" to
hear?



DAB...because of a concerted government, broadcaster and
manufacturing industry push, the likes of which we have not seen in
other countries. A stronger parallel can be drawn to the sizable
takeup of XMRadio and Sirius satellite services in the US and Canada -
the quality stinks but the program choice and wide ranging coverage
are unique.

The quality stinks? Really? I listen to XM streams via the internet,
and they sound just fine. Is there really that huge of a difference
between Internet and Mobile Receiver?



I've been more impressed by synchronous AM demodulation of AM signals
than by a digital equivalent. It's a pity we could not get mass
manufacturing of synch AM radios and ultimately convert all AM
stations to USB with reduced carrier for power savings and reduced
interference.


What's USB? What's synchronous AM demodulation? Thanks.


Synchronous AM demodulation uses a locally regenerated carrier, fed along with the AM signal
(upper or lower set of sidebands) to a multiplier (modulator). The result is the audio. It
replaces the envelope (diode) detector usually used. You can think of it as another superhet
stage where the result, instead of another IF frequency, is the baseband audio. That's
because the local oscillator is the same frequency as the carrier of the (IF) signal, so the
difference is zero. The sidebands wind up translated to baseband audio instead of to
another IF frequency.

There are advantages. Since one set of sidebands or the other can be used, if there's a
distant station 10KHz away, causing that AM whistle, you just switch to the other set of
sidebands, whichever comes in the cleanest. Also, it doesn't depend on proper amplitude and
phase of both sets of sidebands to work properly, as does the regular envelope detector, so
it works better with impaired signals.
--
Regards from Virginia Beach,

Earl Kiosterud
www.smokeylake.com

Earl Kiosterud wrote:

Synchronous AM demodulation uses a locally regenerated carrier, fed along with the AM signal
(upper or lower set of sidebands) to a multiplier (modulator). The result is the audio. It
replaces the envelope (diode) detector usually used. You can think of it as another superhet
stage where the result, instead of another IF frequency, is the baseband audio. That's
because the local oscillator is the same frequency as the carrier of the (IF) signal, so the
difference is zero. The sidebands wind up translated to baseband audio instead of to
another IF frequency.

There are advantages. Since one set of sidebands or the other can be used, if there's a
distant station 10KHz away, causing that AM whistle, you just switch to the other set of
sidebands, whichever comes in the cleanest. Also, it doesn't depend on proper amplitude and
phase of both sets of sidebands to work properly, as does the regular envelope detector, so
it works better with impaired signals.



I only understood about 75% of what your wrote, but if I understand
your meaning, this new receiving technique would not improve the sound
(it would still be limited from 100-6000 hertz), but would only reduce
interference.

In article . com,
SFTV_troy wrote:

Tom wrote:


Snip

You should not be snipping the header of people you reply too. There is
more then one Tom around.

--
Telamon
Ventura, California

On Sep 29, 7:22 pm, SFTV_troy wrote:
Tom wrote:

...So, too, does DRM benefit from said development, making it
possible to provide a digital carrier within LW,MW and SW channeling
plans. Thast said, I find it much less fatiguing to listen to a
program on an analog AM carrier than to the same program over DRM.

I've never heard DRM. How does it sound, and why is it "fatiguing" to
hear?

DAB...because of a concerted government, broadcaster and
manufacturing industry push, the likes of which we have not seen in
other countries. A stronger parallel can be drawn to the sizable
takeup of XMRadio and Sirius satellite services in the US and Canada -
the quality stinks but the program choice and wide ranging coverage
are unique.

The quality stinks? Really? I listen to XM streams via the internet,
and they sound just fine. Is there really that huge of a difference
between Internet and Mobile Receiver?

I've been more impressed by synchronous AM demodulation of AM signals
than by a digital equivalent. It's a pity we could not get mass
manufacturing of synch AM radios and ultimately convert all AM
stations to USB with reduced carrier for power savings and reduced
interference.

What's USB? What's synchronous AM demodulation? Thanks.

Earl answered the last question really well.

DRM (and I imagine HDradio-IBOC-AM) are fatiguing (to some people)
because very low audio encoding bitrates must be employed in order to
fit within the allowed spectrum; typically 10kHz of RF spectrum
restricts the audio to perhaps 20kbps. Considering that a CD streams
at about 75 times this rate, losses in encoding at these very low bit
rates along with the consequent artefacts are pretty severe. Low
bitrate audio tends to have a gurgling, grainy, grungy effect - hard
to describe but after a while, I just have to turn it off. Admittedly,
ambient noise (e.g. road noise) can mask a lot of it but I'm not sure
that it's any less fatiguing.

I was too general in my comment about satellite radio. Both XM and
Sirius use a range of encoding standards, putting news/talk on the
lowest and music on the highest. My main channel on Sirius Canada is
CBC Radio One which was stupidly assigned a news/talk standard when it
actually comprises an eclectic mix of content - we're currently
listening to Randy Bachman (BTO) playing #2 hits from the 60's and
70's in his weekly 3-hour program from the local FM. The Sirius news/
talk encoding is not much higher than 20kbps - voice is bad enough but
music really stinks. The highest standards on XM and Sirius are
better, but like Eureka DAB, frozen in quality at that which could be
provided by the adopted codecs of the day (1990's). What you hear over
the Internet will be encoded differently, using codecs popular for
Internet streaming, not their proprietary ones for satellite delivery.
Both XM and Sirius favour offering more choice than higher quality,
so, like Eureka DAB, subdivide their digital channel capacity into
more, smaller chunks - maybe that's what sells subscriptions - ergo,
lower quality.

Tom

-----------------------------------------------------------------------
"SFTV_troy" wrote in message
ups.com...

Tom wrote:

...So, too, does DRM benefit from said development, making it
possible to provide a digital carrier within LW,MW and SW channeling
plans. Thast said, I find it much less fatiguing to listen to a
program on an analog AM carrier than to the same program over DRM.

I've never heard DRM. How does it sound, and why is it "fatiguing" to
hear?



DAB...because of a concerted government, broadcaster and
manufacturing industry push, the likes of which we have not seen in
other countries. A stronger parallel can be drawn to the sizable
takeup of XMRadio and Sirius satellite services in the US and Canada -
the quality stinks but the program choice and wide ranging coverage
are unique.

The quality stinks? Really? I listen to XM streams via the internet,
and they sound just fine. Is there really that huge of a difference
between Internet and Mobile Receiver?



I've been more impressed by synchronous AM demodulation of AM signals
than by a digital equivalent. It's a pity we could not get mass
manufacturing of synch AM radios and ultimately convert all AM
stations to USB with reduced carrier for power savings and reduced
interference.


What's USB? What's synchronous AM demodulation? Thanks.


I think the USB to which Tom refers is upper sideband. Converting AM stations would mean
they'd transmit only one set of sidebands, the upper set, reducing the bandwidth to almost
half. More stations could be licensed in the same band. A small amount of carrier would
remain, to give the receiver something to lock on to for use in recovery of the audio.
Analog video uses something similar called vestigial sideband, and we could be talking about
that for AM. Conventional radios with envelope (diode) detectors wouldn't work well at all.
When there's only one set of sidebands, with or without the carrier, the envelope of the
composite RF signal doesn't look much like the original audio, and large amounts of
distortion occur.

As a side issue, the loss of fidelity for which AM is notorious is largely in the receivers,
with their narrow bandwidths, resulting in audio that is rolling off pretty fast around the
5 KHz point. (AM stations actually transmit a fairly high-fidelity signal.) This narrow
bandwidth reduces the noise (including the 10 KHz whistle from the carriers of
adjacent-channel stations) that results largely from many distant stations all coming in on
the channel. AM radio, with its low frequencies, travels very far, particularly at night,
so lots of distant stations come roaring in. Converting AM stations to only one sideband
with a reduced carrier would reduce all of that noise. I doubt it will happen.
--
Regards from Virginia Beach,

Earl Kiosterud
www.smokeylake.com

On Sep 29, 4:22 pm, SFTV_troy wrote:
Tom wrote:

...So, too, does DRM benefit from said development, making it
possible to provide a digital carrier within LW,MW and SW channeling
plans. Thast said, I find it much less fatiguing to listen to a
program on an analog AM carrier than to the same program over DRM.

I've never heard DRM. How does it sound, and why is it "fatiguing" to
hear?

DAB...because of a concerted government, broadcaster and
manufacturing industry push, the likes of which we have not seen in
other countries. A stronger parallel can be drawn to the sizable
takeup of XMRadio and Sirius satellite services in the US and Canada -
the quality stinks but the program choice and wide ranging coverage
are unique.

The quality stinks? Really? I listen to XM streams via the internet,
and they sound just fine. Is there really that huge of a difference
between Internet and Mobile Receiver?

XM talk stations are compressed out the wazoo over the bird, while the
internet stream is fair to maybe good, depending on how picky you are.
XM music over the bird is acceptable.

XM PR (Public Radio) is the exception to the rule regarding over
compression. With NPR mixing music with talk, XM needs to be ready for
anything.


I've been more impressed by synchronous AM demodulation of AM signals
than by a digital equivalent. It's a pity we could not get mass
manufacturing of synch AM radios and ultimately convert all AM
stations to USB with reduced carrier for power savings and reduced
interference.

What's USB? What's synchronous AM demodulation? Thanks.