Audio Precision System One Dual Domani Measuirement Systems

[J G Miller]

On Monday, February 6th, 2012, at 16:24:52h +0000, Ron wrote:

Maybe inferior American water takes long to boil anyway compared with
'proper' Bwitish water

Depending on the municipality, the water in the US could have an awful
lot less chlorine (possibly none) than that supplied by one of the big
English water companies.

 

[Geoffrey S. Mendelson]

J G Miller wrote:

Depending on the municipality, the water in the US could have an awful
lot less chlorine (possibly none) than that supplied by one of the big
English water companies.

Not to mention that commie plot FLOURIDATION.

P O E! P O E! P O E!

(does it really need one?)

Geoff.

--
Geoffrey S. Mendelson, N3OWJ/4X1GM
My high blood pressure medicine reduces my midichlorian count. :-(

 

[J G Miller]

On Monday, February 6th, 2012, at 16:19:04h +0000, Geoffrey S. Mendelson asked:

J G Miller wrote:

Carrying a PRI relay of BBC World Service is far cheaper than paying
for NPR programming, so many smaller public radio stations prefer this
option for obvious reasons.

Didn't the Bill and Melinda Gates Foundation help pay for it?

I could be wrong but I do not think that they specifically put any
money into BBC World Service on PRI affiliates. The partnership
between BBC World Service and PRI arose partly out of a joint news
program from Boston and WGBH "The World", and in response to
the BBC stopping their HF service to North America.

The Bill and Melinda Gates Foundation is active in funding a lot
of public radio and TV programming via the CPB for PBS programs
and directly with NPR, and with American Public Media (whose programs
are heard on both NPR affliates and PRI affliates).

 

[J G Miller]

On Monday, February 6th, 2012, at 11:50:27h -0500, Arny Krueger wrote:

Maybe you might want check out the meaning of the word consortium.

Yeah I was just plain wrong to say it was not a consortium --
I should have checked the "finer" details first.

In the case of PBS (television):

1) it is collectively owned by the affiliate stations

2) it produces no programs of its own, but these are supplied by
major stations (eg WETA, WGBH, WNET, KQED) for network viewing by
affliates who have paid the appropriate fee for the program

In the case of NPR (radio):

1) it is a corporation in its own right but stations pay to join as affiliates,
and each member station receives one vote at the annual NPR board meetings

2) NPR produces network programming to which individual stations
can subscribe

 

[Arny Krueger]

"J G Miller" <miller@yoyRG> wrote in message
news:jgp1u0$qka$13@dont-email.me...

On Monday, February 6th, 2012, at 11:50:27h -0500, Arny Krueger wrote:

Maybe you might want check out the meaning of the word consortium.

Yeah I was just plain wrong to say it was not a consortium --
I should have checked the "finer" details first.

In the case of PBS (television):

1) it is collectively owned by the affiliate stations

2) it produces no programs of its own, but these are supplied by
major stations (eg WETA, WGBH, WNET, KQED) for network viewing by
affliates who have paid the appropriate fee for the program

In the case of NPR (radio):

1) it is a corporation in its own right but stations pay to join as
affiliates,
and each member station receives one vote at the annual NPR board
meetings

2) NPR produces network programming to which individual stations
can subscribe

Agreement is a beautiful thing!

 

[Clive]

In message <9pa79fFje3U1@mid.individual.net>, David Looser
<david.looser@btinternet.com> writes

Just on the offchance that you meant this seriously I'd ask just how many
people in the UK would actually want to watch French TV?
UHF only TV's could not receive it.
Many TVs sold in the UK had multiband tuners, and frequency converters were
easily obtainable. So of all the many factors that stopped the British
watching French TV that one was by far and away the easiest and cheapest to
solve.
Don't forget that French SECAM had positive going Video and (I think) AM

sound.
--
Clive

 

[nesesu]

On Feb 6, 3:25 am, Mike Tomlinson <m...@jasper.org.uk> wrote:

In article <PImdnRhFWezLuLHSnZ2dnUVZ_sSdn...@giganews.com>, Arny Krueger
ar...@cocmast.net> writes

I'm not so sure about rings, but the doubled voltage looks good to me given
that I would have enough appliances that ran on 240 volts to be interesting.
I don't.

Think about it - your kettle would boil in half the time

A colleague went to work in the USA and complained about the weedy
kettles over there that take forever to boil.  I suggested he take a UK
230V kettle over with him and run it off an extension to his stove
connection (i.e. 220V).  Dunno if he ever bothered.

--
(\__/)
(='.'=)
(")_(")

Back arounf 1968, my sister sent me a "hot water jug" from Australia
which is a ceramic jug with a plastic lid and a bare ceramic plate
wound with coiled resistance wire immersed in the water at the bottom
of the jug. Since our kitchen was equipped with 'split' appliance
recepticals, I was able to install a standard 15A 230V outlet and
happened to have an ancient [1930s ??] adaptor that converted the
Australian 'Y' plug to NEMA 220V. It was indeed impressive how quickly
it would boil water compared to the then common GE chrome kettles.
I had to replace the element once [she had sent spares], but the jug
was eventually dropped and broken :-(

Neil S

 

[David Looser]

"Clive" <clive@yewbank.demon.co.uk> wrote in message
newsxc8reHCGIMPFwgs@yewbank.demon.co.uk...

In message <9pa79fFje3U1@mid.individual.net>, David Looser
david.looser@btinternet.com> writes
Just on the offchance that you meant this seriously I'd ask just how many
people in the UK would actually want to watch French TV?
UHF only TV's could not receive it.
Many TVs sold in the UK had multiband tuners, and frequency converters
were
easily obtainable. So of all the many factors that stopped the British
watching French TV that one was by far and away the easiest and cheapest
to
solve.

Don't forget that French SECAM had positive going Video and (I think) AM
sound.

True enough. But the original claim was that Britain failed re-use Bands 1 &
3 for TV as UHF only TVs couldn't receive French broadcasts. I was just
pointing that many UK TVs *could * receive VHF. You are quite correct that
French 625-line TV used +ve vision modulation and AM sound which would have
made receiving French TV on UK sets impossible even if we *had* used VHF for
625-line TV.

BTW AM sound was always used with +ve vision modulation. I'm not sure that
there was a killer reason why FM could not have been used with +ve vision
modulation, but intercarrier reception (the cheap'n'easy way to receive FM
sound with TV) wouldn't work with +ve vision modulation unless there was
significant carrier amplitude remaining at the sync tips. Normally with +ve
vision modulation the carrier amplitude at sync tips was nominally zero.

David.

 

[William Sommerwerck]

BTW AM sound was always used with +ve vision modulation. I'm not sure
that
there was a killer reason why FM could not have been used with +ve vision
modulation, but intercarrier reception (the cheap'n'easy way to receive
FM
sound with TV) wouldn't work with +ve vision modulation unless there was
significant carrier amplitude remaining at the sync tips. Normally with
+ve
vision modulation the carrier amplitude at sync tips was nominally zero.

Early US TV sets used separate video and audio IFs -- intercarrier had not
been thought of at that point.

My understanding is that "inverted" polarity was used to minimize the
effects of noise bursts on the sync pulses.

 

[Clive]

In message <9pcgibF7nmU1@mid.individual.net>, David Looser
<david.looser@btinternet.com> writes

BTW AM sound was always used with +ve vision modulation. I'm not sure that
there was a killer reason why FM could not have been used with +ve vision
modulation, but intercarrier reception (the cheap'n'easy way to receive FM
sound with TV) wouldn't work with +ve vision modulation unless there was
significant carrier amplitude remaining at the sync tips. Normally with +ve
vision modulation the carrier amplitude at sync tips was nominally zero.
Many years ago I used to be in to TV and the thought at the time(often

expressed in "Television" magazine) was that the French were
deliberately different to keep manufacturing in France, hence the
positive luminance signal and AM sound. Another example of this was
what used to be called "Peritel" which was mandated for any TV sold in
France to keep out foreigners out. Who would have known at the time
that it would spread and be adopted as the now SCART socket
--
Clive

 

[Arny Krueger]

"William Sommerwerck" <grizzledgeezer@comcast.net> wrote in message
news:jgr9i8$m0e$1@dont-email.me...

BTW AM sound was always used with +ve vision modulation. I'm not sure
that
there was a killer reason why FM could not have been used with +ve
vision
modulation, but intercarrier reception (the cheap'n'easy way to receive
FM
sound with TV) wouldn't work with +ve vision modulation unless there was
significant carrier amplitude remaining at the sync tips. Normally with
+ve
vision modulation the carrier amplitude at sync tips was nominally zero.

Early US TV sets used separate video and audio IFs -- intercarrier had not
been thought of at that point.

My understanding is that "inverted" polarity was used to minimize the
effects of noise bursts on the sync pulses.

That's a good part of it. The net purpose of inverted polarity was to
improve subjective dynamic range. White flecks on a grey background are far
less obvious than black ones.

 

[Terry Casey]

In article <4f2fec88$0$6884$e4fe514c@news2.news.xs4all.nl>,
iimeeltje@hotmail.com.invalid says...

On 2/6/12 1:16 PM, David Looser wrote:

The original plan, drawn up in the early '60s, was to re-engineer Bands 1
and 3 for 625-line operation once the 405-line service was switched off; but
it never happened. I guess that the powers that be thought that the spectrum
could be more usefully used for other purposes.

Of course it could, but harmonizing spectrum with the continent might
have been beneficial as well. Have these plans been published?

I don't see how we could harmonize system I channels with the French 919
line channels!

Other western European countries[1] used system B in a 7MHz channel
width and system G in an 8MHz channel at UHF.

To use the same channels we would have needed to devise a system X with
a truncated vestigial side-band to fit our 6MHz sound-vision spacing
into 7MHz - in reality, I don't think it would have fitted!

In practice, if we had decided to carry on using VHF for 625 line
broadcasting, I think we would have harmonised with the Irish 8MHz
channel plan - not least because of the proximity of NI transmitters to
those in the republic.

[1] Belgium also had its own variant of the French 819 line system
crammed into a standard 7MHz channel - it must have looked truly
appalling in comparison to 625!

--

Terry

 

[David Looser]

"Arny Krueger" <arnyk@cocmast.net> wrote in message
news:nNOdnalSkYctqazSnZ2dnUVZ_rednZ2d@giganews.com...

"William Sommerwerck" <grizzledgeezer@comcast.net> wrote in message
news:jgr9i8$m0e$1@dont-email.me...
BTW AM sound was always used with +ve vision modulation. I'm not sure
that
there was a killer reason why FM could not have been used with +ve
vision
modulation, but intercarrier reception (the cheap'n'easy way to receive
FM
sound with TV) wouldn't work with +ve vision modulation unless there
was
significant carrier amplitude remaining at the sync tips. Normally with
+ve
vision modulation the carrier amplitude at sync tips was nominally
zero.

Early US TV sets used separate video and audio IFs -- intercarrier had
not
been thought of at that point.

My understanding is that "inverted" polarity was used to minimize the
effects of noise bursts on the sync pulses.

That's a good part of it. The net purpose of inverted polarity was to
improve subjective dynamic range. White flecks on a grey background are
far less obvious than black ones.
Umm..No. You've both got it the wrong way round. With -ve polarity sync

pulses are more affected by noise bursts than with +ve polarity. And white
flecks are far more obvious than black. Part of the reason is that impulse
interference could greatly exceed the 100% vision carrier level, saturating
the video amplifier and, with +ve modulation, the CRT.

This was why US TVs, where -ve modulation was used from the beginning,
employed flywheel sync very early on, whilst UK TVs didn't. On the other
hand UK TVs needed peak-white limiters to prevent the CRT defocusing on to
the "whiter-than-white" interference specs.

The real benefit of -ve modulation was AGC. With -ve modulation sync tips
correspond to 100% modulation and make an easy source for the AGC bias. With
+ve modulation sync tips are at zero carrier which obviously is useless for
AGC. Instead the back-porch has to be used and many different weird and
wonderful circuits were devised to "gate out" the signal voltage during the
back porch. Due to the need to keep costs down manufacturers increasingly
turned to "mean-level AGC" in which the video signal itself was simply
low-pass filtered to form the AGC bias. This lead to receiver gain being
varied by the video content, so the black on low-key scenes was boosted
whilst the whites in high-key scenes were reduced leading to a general
greyness to everything. To me it looked awful but as the Great British
Public kept buying these sets (and they were cheaper to build) mean-level
AGC became the norm for B&W UK domestic TV receivers. One great advantage of
colour was that mean-level AGC could not be used, to give correct colour
values colour sets *had* to display a picture with a stable black-level.

David.
>

 

[Geoffrey S. Mendelson]

David Looser wrote:

The real benefit of -ve modulation was AGC. With -ve modulation sync tips
correspond to 100% modulation and make an easy source for the AGC bias. With
+ve modulation sync tips are at zero carrier which obviously is useless for
AGC. Instead the back-porch has to be used and many different weird and
wonderful circuits were devised to "gate out" the signal voltage during the
back porch. Due to the need to keep costs down manufacturers increasingly
turned to "mean-level AGC" in which the video signal itself was simply
low-pass filtered to form the AGC bias. This lead to receiver gain being
varied by the video content, so the black on low-key scenes was boosted
whilst the whites in high-key scenes were reduced leading to a general
greyness to everything. To me it looked awful but as the Great British
Public kept buying these sets (and they were cheaper to build) mean-level
AGC became the norm for B&W UK domestic TV receivers. One great advantage of
colour was that mean-level AGC could not be used, to give correct colour
values colour sets *had* to display a picture with a stable black-level.

We have a PAL TV set that displays bright white as black.

Geoff.

--
Geoffrey S. Mendelson, N3OWJ/4X1GM
My high blood pressure medicine reduces my midichlorian count. :-(

 

[Ian Jackson]

In message <9pcvm1FqgeU1@mid.individual.net>, David Looser
<david.looser@btinternet.com> writes

"Arny Krueger" <arnyk@cocmast.net> wrote in message
news:nNOdnalSkYctqazSnZ2dnUVZ_rednZ2d@giganews.com...

"William Sommerwerck" <grizzledgeezer@comcast.net> wrote in message
news:jgr9i8$m0e$1@dont-email.me...
BTW AM sound was always used with +ve vision modulation. I'm not sure
that
there was a killer reason why FM could not have been used with +ve
vision
modulation, but intercarrier reception (the cheap'n'easy way to receive
FM
sound with TV) wouldn't work with +ve vision modulation unless there
was
significant carrier amplitude remaining at the sync tips. Normally with
+ve
vision modulation the carrier amplitude at sync tips was nominally
zero.

Early US TV sets used separate video and audio IFs -- intercarrier had
not
been thought of at that point.

My understanding is that "inverted" polarity was used to minimize the
effects of noise bursts on the sync pulses.

That's a good part of it. The net purpose of inverted polarity was to
improve subjective dynamic range. White flecks on a grey background are
far less obvious than black ones.
Umm..No. You've both got it the wrong way round. With -ve polarity sync
pulses are more affected by noise bursts than with +ve polarity. And white
flecks are far more obvious than black. Part of the reason is that impulse
interference could greatly exceed the 100% vision carrier level, saturating
the video amplifier and, with +ve modulation, the CRT.

This was why US TVs, where -ve modulation was used from the beginning,
employed flywheel sync very early on, whilst UK TVs didn't. On the other
hand UK TVs needed peak-white limiters to prevent the CRT defocusing on to
the "whiter-than-white" interference specs.

The real benefit of -ve modulation was AGC. With -ve modulation sync tips
correspond to 100% modulation and make an easy source for the AGC bias. With
+ve modulation sync tips are at zero carrier which obviously is useless for
AGC. Instead the back-porch has to be used and many different weird and
wonderful circuits were devised to "gate out" the signal voltage during the
back porch. Due to the need to keep costs down manufacturers increasingly
turned to "mean-level AGC" in which the video signal itself was simply
low-pass filtered to form the AGC bias. This lead to receiver gain being
varied by the video content, so the black on low-key scenes was boosted
whilst the whites in high-key scenes were reduced leading to a general
greyness to everything. To me it looked awful but as the Great British
Public kept buying these sets (and they were cheaper to build) mean-level
AGC became the norm for B&W UK domestic TV receivers. One great advantage of
colour was that mean-level AGC could not be used, to give correct colour
values colour sets *had* to display a picture with a stable black-level.

Even with negative video modulation, it didn't seem to take the

Americans long to realise that they could cut costs by using AC coupling
in the video amplifier between the video detector and the CRT. [I've got
some old US monochrome TV circuits which definitely show AC coupling.]
As a result, the benefits of having an AGC line which didn't vary (much)
with video content would be essentially lost.

Regarding using the back porch as the signal reference, and deriving the
AGC from it, I recall a Wireless World article in around 1967,
describing a simple add-on circuit (which I made) which partly did this.
It worked both on 405 and 626-line signals. It wasn't intended to
improve the horrible mean-level AGC but, at the start of each video
line, it did clamp the video drive (to the cathode of the CRT) to the
black reference of the back porch. As a result, you still got the
contrast varying with video content (maybe not so much on 625), but at
least the black stayed (more-or-less) black.
--
Ian

 

[Ian Jackson]

In message <MPG.299b4fb86cac4d2398970d@news.eternal-september.org>,
Terry Casey <k.type@example.invalid> writes

In article <4f2fec88$0$6884$e4fe514c@news2.news.xs4all.nl>,
iimeeltje@hotmail.com.invalid says...

On 2/6/12 1:16 PM, David Looser wrote:

The original plan, drawn up in the early '60s, was to re-engineer Bands 1
and 3 for 625-line operation once the 405-line service was switched
off; but
it never happened. I guess that the powers that be thought that the
spectrum
could be more usefully used for other purposes.

Of course it could, but harmonizing spectrum with the continent might
have been beneficial as well. Have these plans been published?


I don't see how we could harmonize system I channels with the French 919
line channels!

Other western European countries[1] used system B in a 7MHz channel
width and system G in an 8MHz channel at UHF.

To use the same channels we would have needed to devise a system X with
a truncated vestigial side-band to fit our 6MHz sound-vision spacing
into 7MHz - in reality, I don't think it would have fitted!

Of course, both the British and the Irish could have simply adopted the

European systems B and G (5.5MHz sound-vision - plus the horrendous
group delay pre-correction curve). If I remember correctly, the only
difference between systems B and G is the 7 vs 8 MHz channel spacing.
Even the VSBs are the same (0.75MHz).

In practice, if we had decided to carry on using VHF for 625 line
broadcasting, I think we would have harmonised with the Irish 8MHz
channel plan - not least because of the proximity of NI transmitters to
those in the republic.

Again, IIRC, the RoI VHF 625-line channels were the same frequencies as

the 'lettered' 625-line channels already used on many VHF cable TV
systems.

Belgium also had its own variant of the French 819 line system
crammed into a standard 7MHz channel - it must have looked truly
appalling in comparison to 625!

I think that these had gone well before I got involved!

--
Ian

 

[J. P. Gilliver (John)]

In message <YOROUeHg$7LPFwNm@jasper.org.uk>, Mike Tomlinson
<mike@jasper.org.uk> writes:

In article <Wdmdnffl5IsuA7DSnZ2dnUVZ_qmdnZ2d@giganews.com>, Arny Krueger
arnyk@cocmast.net> writes

http://hostedmedia.reimanpub.com/TFH/Step-By-Step/display/FH01NOV_OUTLE
T_03.jpg

The ground wires in that picture appear to be in bare copper, borne out
by the person using a multimeter with a probe resting on the ground
wire. If so, that's pretty shoddy. What's to stop it coming into
contact with the exposed hot and neutral screws on the outlet body as
the outlet is pushed back into the box?

UK wiring regulations require earth (ground) wires to be sheathed in
green and yellow sleeving where it is exposed.

I have often been puzzled by this requirement. What is the reason - just

identification of the earth wire, or something else?
--
J. P. Gilliver. UMRA: 1960/<1985 MB++G.5AL-IS-P--Ch++(p)Ar@T0H+Sh0!:`)DNAf

Times are bad. Children no longer obey their parents, and everyone is writing a
book. -Marcus Tullius Cicero, statesman, orator and writer (106-43 BCE)

 

[J. P. Gilliver (John)]

In message <EtKdnfMulLSnfbLSnZ2dnUVZ_judnZ2d@giganews.com>, Arny Krueger
<arnyk@cocmast.net> writes:
[]

Oh good, we're going to argue about who can boil a kettle the fastest...
you couldn`t make it up!

No argument - the UK ring system seems to be vastly superior over our US 15
and 20 amp circuits when it comes to delivering more actual AC power to
appliances.


I think the voltage in use probably has about as much relevance as the

wiring system - at twice the voltage, the same power will require half
the current anyway. Doubling the wire as well obviously increases the
capacity too (or, allows the same capacity with thinner wire - though
I'm not as convinced by that argument as some).
--
J. P. Gilliver. UMRA: 1960/<1985 MB++G.5AL-IS-P--Ch++(p)Ar@T0H+Sh0!:`)DNAf

Times are bad. Children no longer obey their parents, and everyone is writing a
book. -Marcus Tullius Cicero, statesman, orator and writer (106-43 BCE)

 

[J. P. Gilliver (John)]

In message <9pacbsFqtlU1@mid.individual.net>, David Looser
<david.looser@btinternet.com> writes:
[]

Well it might, but in practice there don't seem to have been many problems
caused by not harmonising spectrum use with the the continent. To be honest
I think the government made the right decision, the limited VHF spectrum
available in Bands 1 & 3 would only just have been enough for one extra
625-line TV channel.
[]

? - one on band I and at least one on band III, surely? I lived in
(West) Germany in the 1960s and '70s, and I'm sure we could get at least
two channels on band III (yes, I know B and G channels are narrower, but
not that much).
--
J. P. Gilliver. UMRA: 1960/<1985 MB++G.5AL-IS-P--Ch++(p)Ar@T0H+Sh0!:`)DNAf

Times are bad. Children no longer obey their parents, and everyone is writing a
book. -Marcus Tullius Cicero, statesman, orator and writer (106-43 BCE)

 

[Dave Plowman (News)]

In article <buZ2G1VrVaMPFwno@soft255.demon.co.uk>,
J. P. Gilliver (John) <G6JPG@soft255.demon.co.uk> wrote:

UK wiring regulations require earth (ground) wires to be sheathed in
green and yellow sleeving where it is exposed.

I have often been puzzled by this requirement. What is the reason - just
identification of the earth wire, or something else?

It's just belt and braces - slightly less chance of a short if wires get
trapped by careless assembly.

--
*If horrific means to make horrible, does terrific mean to make terrible?

Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.