In article ,
"David Eduardo" wrote:

"Telamon" wrote in message
news:telamon_spamshield-
I don't need to get an HD radio and drive around LA. This is just plain
physics. Information transmitted is determined by the amount of power
and bandwidth applied to a signal. You can not have a more reliable
transmittal of a signal on less power and bandwidth. Do you get the
picture?

No, because the limiting factor on analog is, in most cases, noise. The
digital system itself has better system specs, and the reception systems can
make use of a much weaker digital signal than they can an analog one.

You can say no all you want. What I stated is the basic principles of
information transmission. Go look it up. Too bad if you don't like it.

Noise lowers the dynamic range available for digital and analog
transmissions. Too bad if you don't want to hear that either because
that is the way the ball bounces. People that do not know what they are
talking about may think otherwise but that does not change reality for
them or the rest of us.

--
Telamon
Ventura, California

"Telamon" wrote in message
...
In article ,
"David Eduardo" wrote:

"Telamon" wrote in message
news:telamon_spamshield-
I don't need to get an HD radio and drive around LA. This is just plain
physics. Information transmitted is determined by the amount of power
and bandwidth applied to a signal. You can not have a more reliable
transmittal of a signal on less power and bandwidth. Do you get the
picture?

No, because the limiting factor on analog is, in most cases, noise. The
digital system itself has better system specs, and the reception systems
can
make use of a much weaker digital signal than they can an analog one.

You can say no all you want. What I stated is the basic principles of
information transmission. Go look it up. Too bad if you don't like it.

I had an interesting discussion with our engineering department in LA this
morning...

The general consensus as to why far less signal is about as effective has to
do with noise. A digital signal can be correctly decoded even when there is
noise just a few db below the signal itself. HD duplicates the same data on
both sides of the carrier, so there is the ability to select the best data,
much like diversity reception. And HD "dithers" in the case of small
dropouts.

Analog requires something over a -57 db noise floor to be useful to the
average listener, and something in the -60's for really nice FM reception.

All the engineers (and there are 8 of them for our 5 signals) believed, in
conclusion, that the determining factor on usability on an analog signal is
also noise, which is why in LA we get no listeing outside the 64 dbu on FM
and about the 10 to 12 mv/m daytime and the 15 mv/m night on AM.


Noise lowers the dynamic range available for digital and analog
transmissions. Too bad if you don't want to hear that either because
that is the way the ball bounces. People that do not know what they are
talking about may think otherwise but that does not change reality for
them or the rest of us.

The reality is that the HD data can be extracted and DACed when the noise is
only a few db below the signal itself.

In article ,
"David Eduardo" wrote:

"Telamon" wrote in
message

.com...
In article , "David
Eduardo" wrote:

"Telamon" wrote in
message news:telamon_spamshield-
I don't need to get an HD radio and drive around LA. This is
just plain physics. Information transmitted is determined by the
amount of power and bandwidth applied to a signal. You can not
have a more reliable transmittal of a signal on less power and
bandwidth. Do you get the picture?

No, because the limiting factor on analog is, in most cases,
noise. The digital system itself has better system specs, and the
reception systems can make use of a much weaker digital signal
than they can an analog one.

You can say no all you want. What I stated is the basic principles
of information transmission. Go look it up. Too bad if you don't
like it.

I had an interesting discussion with our engineering department in LA
this morning...

The general consensus as to why far less signal is about as effective
has to do with noise. A digital signal can be correctly decoded even
when there is noise just a few db below the signal itself.

The claim here "can be correctly decoded even when there is noise just
a few db below the signal itself" is no more possible than an analog
signal can be heard a few dB over the noise floor. Now both these
claims depend on the probability of the ratio of the instantaneous
noise power over the instantaneous signal modulation power.

HD duplicates the same data on both sides of the carrier, so there is
the ability to select the best data, much like diversity reception.
And HD "dithers" in the case of small dropouts.

This is a rational explanation based on the argument that the total
bandwidth utilized by the digital mode may be better utilized over the
analog mode but this depends on wether an analog radio output employing
an envelope detector suffers when one side band degrades. Ask your
engineering buddies.

Analog requires something over a -57 db noise floor to be useful to
the average listener, and something in the -60's for really nice FM
reception.

Arbitrary numbers that do not account for individual reception
situations.

All the engineers (and there are 8 of them for our 5 signals)
believed, in conclusion, that the determining factor on usability on
an analog signal is also noise, which is why in LA we get no listeing
outside the 64 dbu on FM and about the 10 to 12 mv/m daytime and the
15 mv/m night on AM.

OK it is fine to set limits on what is considered good or bad signal to
noise but that does not change the fact that when the signal to noise is
small both HD and analog are not easy to listen too.

Noise lowers the dynamic range available for digital and analog
transmissions. Too bad if you don't want to hear that either
because that is the way the ball bounces. People that do not know
what they are talking about may think otherwise but that does not
change reality for them or the rest of us.

The reality is that the HD data can be extracted and DACed when the
noise is only a few db below the signal itself.

What do you mean by "DACed." If you mean digital to analog converter I
hope you understand that every time an analog signal goes through the
process of analog to digital conversion at the transmitter and then
digital to analog in the receiver that a set of errors and distortion is
added to the resulting analog signal but that is not the argument you
are trying to make.

Can you understand that as the signal level approaches the noise floor
that the probability of the 1/0 data stream being correctly detected
decreases? If the data stream becomes corrupted and then converted to
analog it will not represent the original programing now will it. Can
you see the similarity to analog in this regard?

--
Telamon
Ventura, California

"Telamon" wrote in message
...
In article ,
"David Eduardo" wrote:

The general consensus as to why far less signal is about as effective
has to do with noise. A digital signal can be correctly decoded even
when there is noise just a few db below the signal itself.

The claim here "can be correctly decoded even when there is noise just
a few db below the signal itself" is no more possible than an analog
signal can be heard a few dB over the noise floor. Now both these
claims depend on the probability of the ratio of the instantaneous
noise power over the instantaneous signal modulation power.

The HD signal is digital. The noise is not, it is analog. As long as there
is enough digital data to extract, the analog noise is not the issue.

HD duplicates the same data on both sides of the carrier, so there is
the ability to select the best data, much like diversity reception.
And HD "dithers" in the case of small dropouts.

This is a rational explanation based on the argument that the total
bandwidth utilized by the digital mode may be better utilized over the
analog mode but this depends on wether an analog radio output employing
an envelope detector suffers when one side band degrades. Ask your
engineering buddies.

We are talking about the ability to receive a substantially intact digital
data stream in an analog noise filled environment. This can be done with the
noise floor just a few db below the digital data. In analog, the noise and
the information you wish to recover are both analog and mix. So the signal
has to be significantly, on the order of around 60 db, above the noise
floor. So, tihe a difference of perhaps 57 db between digital and analog
usability, low power on the digital can produce excellent results.

BTW, I have been lead engineer for a group of a dozen stations, including
building the transmitters and studio gear from scratch. I talk to our
engineers often because we use technology to our advantage to create better
radio stations.

Analog requires something over a -57 db noise floor to be useful to
the average listener, and something in the -60's for really nice FM
reception.

Arbitrary numbers that do not account for individual reception
situations.

Wrong. Analong noise and signal combine. Digital can be plucked out of the
analog noise. And for analog, the noise has to be around -57 db or the
average listener finds it noise and unlistenable. This is why below the 64
dbu contour of the average radio station there is essentially no
listening... it is too noisy.

All the engineers (and there are 8 of them for our 5 signals)
believed, in conclusion, that the determining factor on usability on
an analog signal is also noise, which is why in LA we get no listeing
outside the 64 dbu on FM and about the 10 to 12 mv/m daytime and the
15 mv/m night on AM.

OK it is fine to set limits on what is considered good or bad signal to
noise but that does not change the fact that when the signal to noise is
small both HD and analog are not easy to listen too.

The HD digital stream can be picked out of the analog noise. The analog
signal becomes a part of it and is inseparabble.


The reality is that the HD data can be extracted and DACed when the
noise is only a few db below the signal itself.

What do you mean by "DACed." If you mean digital to analog converter I
hope you understand that every time an analog signal goes through the
process of analog to digital conversion at the transmitter and then
digital to analog in the receiver that a set of errors and distortion is
added to the resulting analog signal but that is not the argument you
are trying to make.

Of course I understand that. The fact is, the last step of a digital
transmission system is to do a digital to analog conversion, since the ear
is not digital.

Can you understand that as the signal level approaches the noise floor
that the probability of the 1/0 data stream being correctly detected
decreases? If the data stream becomes corrupted and then converted to
analog it will not represent the original programing now will it. Can
you see the similarity to analog in this regard?

No, I understand that the noise is analog. And the HD stream is digital, and
once detected is separable from the noise. Not so in analog. The data stream
is redundant (to each side of the carrier center, and has dithering as well.
If the digital signal fails, it falls back to analog. However, as stated,
the analog signal gets essentially no listening beyond the 64 dbu curve due
to... you asked for it... NOISE!