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| GregS... |
 Posted: Fri Nov 06, 2009 1:46 pm |
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You find all the info in the spectrum of the analog TV broadcast.
Where is the description of the transmitted digital signal,
and I would like to see a spectrum of the output. ??
greg |
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| Phil Allison... |
| Posted: Fri Nov 06, 2009 4:56 pm |
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"GregS"
[quote]Where is the description of the transmitted digital signal,
[/quote]
Fo the system used in the USA see:
http://en.wikipedia.org/wiki/8VSB
[quote]and I would like to see a spectrum of the output. ??
[/quote]
** AFAIK it looks very much like noise.
..... Phil |
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| Glenn Gundlach... |
| Posted: Fri Nov 06, 2009 9:23 pm |
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On Nov 6, 10:46 am, zekfr... at (no spam) zekfrivolous.com (GregS) wrote:
[quote]You find all the info in the spectrum of the analog TV broadcast.
Where is the description of the transmitted digital signal,
and I would like to see a spectrum of the output. ??
greg
[/quote]
I was trying to find this earlier but I was at work.
http://www.hdtvprimer.com/ISSUES/what_is_ATSC.html
The spectrum displays at the bottom of the page are indeed accurate.
G² |
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| miso at (no spam) sushi.com... |
| Posted: Fri Nov 06, 2009 10:02 pm |
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On Nov 6, 11:23 pm, Glenn Gundlach <stratu... at (no spam) yahoo.com> wrote:
[quote]On Nov 6, 10:46 am, zekfr... at (no spam) zekfrivolous.com (GregS) wrote:
> You find all the info in the spectrum of the analog TV broadcast.
> Where is the description of the transmitted digital signal,
> and I would like to see a spectrum of the output. ??
> greg
I was trying to find this earlier but I was at work.
http://www.hdtvprimer.com/ISSUES/what_is_ATSC.html
The spectrum displays at the bottom of the page are indeed accurate.
G²
[/quote]
Eighteen formats. Insanity cubed! |
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| Glenn Gundlach... |
| Posted: Sun Nov 08, 2009 6:51 pm |
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On Nov 7, 12:02 am, "m... at (no spam) sushi.com" <m... at (no spam) sushi.com> wrote:
[quote]On Nov 6, 11:23 pm, Glenn Gundlach <stratu... at (no spam) yahoo.com> wrote:
On Nov 6, 10:46 am, zekfr... at (no spam) zekfrivolous.com (GregS) wrote:
> You find all the info in the spectrum of the analog TV broadcast.
> Where is the description of the transmitted digital signal,
> and I would like to see a spectrum of the output. ??
> greg
I was trying to find this earlier but I was at work.
http://www.hdtvprimer.com/ISSUES/what_is_ATSC.html
The spectrum displays at the bottom of the page are indeed accurate.
G²
Eighteen formats. Insanity cubed!
[/quote]
When you let computer people get involved, what do you expect?
G² |
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| Glenn Gundlach... |
| Posted: Tue Nov 10, 2009 6:15 am |
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On Nov 10, 6:31 am, zekfr... at (no spam) zekfrivolous.com (GregS) wrote:
[quote]In article <7ljkbnF3e6al... at (no spam) mid.individual.net>, "Phil Allison"
phi... at (no spam) tpg.com.au> wrote:
"GregS"
Where is the description of the transmitted digital signal,
Fo the system used in the USA see:
http://en.wikipedia.org/wiki/8VSB
and I would like to see a spectrum of the output. ??
** AFAIK it looks very much like noise.
..... Phil
I see that on the other posters response link.
I was listening on my detector last week and didn't pic up anything
audible. Will check it again with a simple spectrum analyzer later.
With analog, I heard the video as it was being detected with the
input of a simple
op-amp amplifier. Basically sounding like when you plugged the
video
into an audio input by mistake.
Interference, mostly in the audible band has been the main cause
for concern from a nearby tower about 500 feet away, with the old
analog. They just started
broadcasting digital last week and I am checking for common noise
problems detected with sensitive lab equipment.
Construction in new buildings specified aluminum backed drywall
because
of this tower.
greg
[/quote]
DTV is supposed to resemble noise by design. They also run much lower
power output than the old analog system so there isn't as much signal
to mess up your gear.
http://www.hdtvprimer.com/ISSUES/what_is_ATSC.html
Load this page and search 'sideband' to see what you will see on your
spectrum analyzer.
G² |
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| GregS... |
| Posted: Tue Nov 10, 2009 9:31 am |
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In article <7ljkbnF3e6allU1 at (no spam) mid.individual.net>, "Phil Allison" <phil_a at (no spam) tpg.com.au> wrote:
[quote]
"GregS"
Where is the description of the transmitted digital signal,
Fo the system used in the USA see:
http://en.wikipedia.org/wiki/8VSB
and I would like to see a spectrum of the output. ??
** AFAIK it looks very much like noise.
..... Phil
[/quote]
I see that on the other posters response link.
I was listening on my detector last week and didn't pic up anything
audible. Will check it again with a simple spectrum analyzer later.
With analog, I heard the video as it was being detected with the input of a simple
op-amp amplifier. Basically sounding like when you plugged the video
into an audio input by mistake.
Interference, mostly in the audible band has been the main cause
for concern from a nearby tower about 500 feet away, with the old analog. They just started
broadcasting digital last week and I am checking for common noise
problems detected with sensitive lab equipment.
Construction in new buildings specified aluminum backed drywall because
of this tower.
greg |
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| Paul Keinanen... |
| Posted: Tue Nov 10, 2009 11:08 am |
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Guest
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On Sat, 7 Nov 2009 00:02:02 -0800 (PST), "miso at (no spam) sushi.com"
<miso at (no spam) sushi.com> wrote:
[quote]On Nov 6, 11:23 pm, Glenn Gundlach <stratu... at (no spam) yahoo.com> wrote:
On Nov 6, 10:46 am, zekfr... at (no spam) zekfrivolous.com (GregS) wrote:
> You find all the info in the spectrum of the analog TV broadcast.
> Where is the description of the transmitted digital signal,
> and I would like to see a spectrum of the output. ??
> greg
I was trying to find this earlier but I was at work.
http://www.hdtvprimer.com/ISSUES/what_is_ATSC.html
The spectrum displays at the bottom of the page are indeed accurate.
G²
Eighteen formats. Insanity cubed!
[/quote]
Once you have to support more than one format _or_ have to support a
different display rate (say SD) than broadcast rate, you are going to
have to use some standard conversion anyway. Adding two or twenty
format is then no longer an issue.
Paul |
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| Mark... |
| Posted: Tue Nov 10, 2009 11:25 am |
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On Nov 10, 9:31 am, zekfr... at (no spam) zekfrivolous.com (GregS) wrote:
[quote]In article <7ljkbnF3e6al... at (no spam) mid.individual.net>, "Phil Allison" <phi... at (no spam) tpg.com.au> wrote:
"GregS"
Where is the description of the transmitted digital signal,
Fo the system used in the USA see:
http://en.wikipedia.org/wiki/8VSB
and I would like to see a spectrum of the output. ??
** AFAIK it looks very much like noise.
..... Phil
I see that on the other posters response link.
I was listening on my detector last week and didn't pic up anything
audible. Will check it again with a simple spectrum analyzer later.
With analog, I heard the video as it was being detected with the input of a simple
op-amp amplifier. Basically sounding like when you plugged the video
into an audio input by mistake.
Interference, mostly in the audible band has been the main cause
for concern from a nearby tower about 500 feet away, with the old analog. They just started
broadcasting digital last week and I am checking for common noise
problems detected with sensitive lab equipment.
Construction in new buildings specified aluminum backed drywall because
of this tower.
greg- Hide quoted text -
- Show quoted text -
[/quote]
RFI from analog video sounded like a buzz as you described.
RFI from 8VSB will sound like a hiss.
There is a lot less energy in the audio range with 8VSB so RFI from TV
into audio gear should be less prevelent but since it no longer
creates that distinvtive buzz, it will be harder to identifiy.
Mark |
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| Phil Allison... |
| Posted: Tue Nov 10, 2009 5:40 pm |
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Guest
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"Mark"
RFI from analog video sounded like a buzz as you described.
RFI from 8VSB will sound like a hiss.
** Not in audio gear it won't.
There is a lot less energy in the audio range with 8VSB so RFI from TV
into audio gear should be less prevelent but since it no longer
creates that distinvtive buzz, it will be harder to identifiy.
** It simply will not be rectified to an audible frequency.
..... Phil |
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