rickman wrote:
On 2/24/2015 6:35 PM, gareth wrote:
"rickman" wrote in message
...
On 2/24/2015 12:37 PM, gareth wrote:
"Spike" wrote in message
...
Get a CW signal peaked on the 20 c/s nose of the HRO crystal filter,
with
the phasing notching out any nearby signal, and you realise that DSP
just
isn't necessary due to the quality of the 80-year-old technology
employed.

WHS.

The Eddystone EA12 does not have a phasing control as that part of the
cct
is fixed-tuned, but it does have a tunable notch in the 100kHz IF to
achieve the same effect.

Mind you, there seems to be a diminishing band of people who know how to
do this, so the simplistic approach of using someone else's
ever-upgraded
software to do something less effective is about as far as the tick-box
Amateur seems to go. Heavens - they even buy ready-made wire aerials!

And going from previous threads, there are even fewer who understand that
setting up for single-signal reception means that the notional carrier
frequency has
to lie half-way between the peak of the Xtal and the notch of the phasing
control.

We should not forget that he who sneers loud and long about others' grasp
of
the mathematics of DSP maintains that changing the direction of a
rotating
vector
(A Phasor, and not related to the weapons of Star Trek!) causes it to
decrease in sixe.

What is "sixe"???

Typo - adjacent key - size

I thought it might be that, but it still makes no sense to me. Who or
how does changing the direction of rotation of a rotating vector change
its "size". Are you defining size as the rotation so that going from a +
to a - is like reversing the direction of a vector? I think most people
would consider the "size" of a vector to be the magnitude which is
independent of phase angle and so rotation, no?

Perhaps you can explain this with a little math?

Sadly, Gareth absolutely cannot explain it. He doesn't remotely understand
anything he's talking about, as per.

--
STC // M0TEY // twitter.com/ukradioamateur

On 25/02/15 06:45, rickman wrote:
On 2/24/2015 7:32 PM, Brian Reay wrote:
rickman wrote:
On 2/24/2015 6:35 PM, gareth wrote:
"rickman" wrote in message
...
On 2/24/2015 12:37 PM, gareth wrote:
"Spike" wrote in message
...
Get a CW signal peaked on the 20 c/s nose of the HRO crystal filter,
with
the phasing notching out any nearby signal, and you realise that DSP
just
isn't necessary due to the quality of the 80-year-old technology
employed.

WHS.

The Eddystone EA12 does not have a phasing control as that part of
the
cct
is fixed-tuned, but it does have a tunable notch in the 100kHz IF to
achieve the same effect.

Mind you, there seems to be a diminishing band of people who know
how to
do this, so the simplistic approach of using someone else's
ever-upgraded
software to do something less effective is about as far as the
tick-box
Amateur seems to go. Heavens - they even buy ready-made wire
aerials!

And going from previous threads, there are even fewer who
understand that
setting up for single-signal reception means that the notional
carrier
frequency has
to lie half-way between the peak of the Xtal and the notch of the
phasing
control.

We should not forget that he who sneers loud and long about
others' grasp
of
the mathematics of DSP maintains that changing the direction of a
rotating
vector
(A Phasor, and not related to the weapons of Star Trek!) causes it to
decrease in sixe.

What is "sixe"???

Typo - adjacent key - size

I thought it might be that, but it still makes no sense to me. Who or
how does changing the direction of rotation of a rotating vector change
its "size". Are you defining size as the rotation so that going from
a +
to a - is like reversing the direction of a vector? I think most people
would consider the "size" of a vector to be the magnitude which is
independent of phase angle and so rotation, no?

Perhaps you can explain this with a little math?


He is (deliberately) misrepresenting the discussion. The point was made
that the phasor was rotating clockwise, thus the angle decreasing, ie
becoming negative.

This has been repeatedly explained to him but he continues to churn
out his
bilge.

His maths (or math) isn't up to it, it is too complex for him (pun
intended).

If you look in the archives you will see him referring to 'negative
frequency', not to mention questioning basic DSP theory, the use of the
Dirac Delta, .....

Best just to ignore him, he is simply trying to start a row.

Maybe I don't understand the issue. Isn't that a valid example of a
negative frequency? There are some DSP experts in comp.dsp who talk
about negative frequency often.


I went over this at the time, although in connection with another of his
wild claims (he claimed that you couldn't divide complex numbers).

Basically, the mathematical concept, which wasn't Evans' point, of
negative frequency arises from Euler's Identities for sin (theta) and
cos (theta) which leads to the result that a simple, real, sinusoid, is
the sum (using Euler's Identities) of positive and negative terms. In
DSP circles, the negative terms, are generally referred to the 'negative
frequency terms' (or some variation, depending on local usage). These
are generally removed, or filtered (numerically) to simplify the overall
processing task.


If you dig into the archive to the time when Evans first raised this,
you will see he was clearly not referring to 'negative frequency' in
terms of the above. I pointed out his error, although I did under
estimate his lack of understanding and/or ability to twist facts. This
is one of the topics he drags up after a drubbing and he promptly gets
another one.

On 25/02/15 08:53, Stephen Thomas Cole wrote:
rickman wrote:


Perhaps you can explain this with a little math?

Sadly, Gareth absolutely cannot explain it. He doesn't remotely understand
anything he's talking about, as per.


That is a major part of his problem. He just isn't up to the level of
technical stuff he aspires to, in fact he has glaring gaps in even the
basics.

Rather than try and learn, he tries to bluff that he knows far more than
he does. When he is shown to be a charlatan, he turns to abuse. Even
that is predictable in the path it will take, including his most extreme
steps.



As you say, he is best ignored, although some of his whacky theories
have given me a good laugh from time to time.

"rickman" wrote in message
...

I thought it might be that, but it still makes no sense to me. Who or how
does changing the direction of rotation of a rotating vector change its
"size". Are you defining size as the rotation so that going from a + to
a - is like reversing the direction of a vector? I think most people
would consider the "size" of a vector to be the magnitude which is
independent of phase angle and so rotation, no?

Perhaps you can explain this with a little math?

Not my gibberish, refer to the original posting ...

-----ooooo-----

From: "Brian Reay"
Newsgroups: alt.engineering.electrical,uk.radio.amateur
Subject: Phase noise
Date: Sat, 13 Dec 2003 10:21:54 -0000
Message-ID:


The term e^(-jwt) isn't some magical time machine relating to "minus
time", e^(-jwt) is simply another way of writing 1/(e^jwt) which
is a value that decreases as t increasing.

"Brian Reay" wrote in message
...


He is (deliberately) misrepresenting the discussion. The point was made
that the phasor was rotating clockwise, thus the angle decreasing, ie
becoming negative.

Untrue, no mention of the angle, as below ...

-----ooooo-----

From: "Brian Reay"
Newsgroups: alt.engineering.electrical,uk.radio.amateur
Subject: Phase noise
Date: Sat, 13 Dec 2003 10:21:54 -0000
Message-ID:

Equally, it is easy to mis-interpret the maths as Gareth has done in:

cos(wt) = 1/2 * ( e^(jwt) +e^(-jwt) )

The term e^(-jwt) isn't some magical time machine relating to "minus
time", e^(-jwt) is simply another way of writing 1/(e^jwt) which
is a value that decreases as t increasing.

-----ooooo-----



This has been repeatedly explained to him but he continues to churn out
his
bilge.
His maths (or math) isn't up to it, it is too complex for him (pun
intended).
If you look in the archives you will see him referring to 'negative
frequency', not to mention questioning basic DSP theory, the use of the
Dirac Delta, .....

Well, that just looke like a desperate attempt to save face by resorting
to rather silly and infantile abuse, not deserving of a reply.

Best just to ignore him, he is simply trying to start a row.

Do you think, perhaps, that your repeated-ad-nauseam sneers about
DSP mathematics capability over the past week has that characteristic?

Really, Brian, in that respect it is a case both of, "Physician, heal
thyself!"
and also of, "Hoist by your own petard".

Let me give you a bit of advice, which is to concentrate on behaving
as a grown-up in the international forum which is Usenet, because
if you **** into the wind, as you seem intent on doing every day, every
hour even, then you _WILL_ get your own back.

Jerry Stuckle wrote:

On 2/24/2015 7:03 PM, rickman wrote:
On 2/24/2015 6:37 PM, Jerry Stuckle wrote:
On 2/24/2015 5:47 PM, rickman wrote:
On 2/24/2015 12:00 PM, Jerry Stuckle wrote:
On 2/24/2015 11:32 AM, FranK Turner-Smith G3VKI wrote:
"AndyW" wrote in message
...
On 24/02/2015 12:47, gareth wrote:
What is the point of digital voice when there are already AM, SSB
and FM for those who want to appear indistinguishable from CBers?

Perhaps it is cynicism from the manufacturers who introduce such
things
as they see their traditional highly-priced corner of the market
being wiped away by SDR technologies?

Bandwidth reduction for one.
If you can encode and compress speech sufficiently then you can use
less bandwidth in transmission.

That's the bit I have trouble getting my head around. Back in the
1970s
and 1980s digital transmissions used a much greater bandwidth than
their
analogue equivalents. Sampling at 2.2 x max frequency x number of bits
plus housekeeping bits etc. etc.
A UK standard 625 line PAL video transmission would have used a
bandwidth of over 400MHz!
Times have changed and left me behind, but I've still got me beer
so who
cares?

But you forget compression. For instance, unless there is a scene
change, the vast majority of a television picture does not change from
frame to frame. Even if the camera moves, the picture shifts but
doesn't change all that much. Why waste all of that bandwidth
resending
information the receiver already has?

And voice isn't continuous; it has lots of pauses. Some are very
noticeable, while others are so short we don't consciously hear them,
but they are there.

And once you've compressed everything you can out of the original
signal, you can do bit compression, similar to zipping a file for
sending.

There are lots of ways to compress a signal before sending it
digitally.
About the only one which can't be compressed is pure white noise -
which, of course, is only a concept (nothing is "pure").

I think that depends on what you mean by "pure". Sounds very
non-technical to me. Even noise can be compressed since if it is truly
noise, you don't need to send the data, just send the one bit that says
there is no signal, just noise. lol


Pure white noise is a random distribution of signal across the entire
spectrum, with an equal distribution of frequencies over time. Like a
pure resistor or capacitor, it doesn't exist. But the noise IS the
signal. To recreate the noise, you have to sample the signal and
transmit it. However, since it is completely random, by definition no
compression is possible.

Why does it not "exist"? That is not at all clear. You don't
understand compression. Compression is a means of removing the part of
a signal that is unimportant and sending only the part that is
important. In most cases of "pure" noise, you can just send a statement
that the signal is "noise" without caring about the exact voltages over
time. So, yes, even noise can be compressed depending on your
requirements.


Pure white noise is a concept only. There is no perfect white noise
source, just as there is no pure resistor or capacitor.

And yes, I do understand compression. One of the things it depends on
is predictability and repeatability of the incoming signal. That does
not exist with white noise. The fact you don't understand that pure
white noise is only a concept and cannot exist in the real world shows
your lack of understanding.

Some compression algorithms (i.e. mp3) remove what they consider is
"unimportant". However, the result after decompressing is a poor
recreation of the original signal.

But for perfect recreation, nothing is "unimportant". Voice/video
compression is no different than file compression on a computer. Can
you imaging what would happen if your favorite program was not perfectly
recreated?


A friend worked in sonar where the data was collected on ships and
transmitted via satellite to shore for signal processing rather than
doing any compression on the data and sending the useful info. As the
signal was nearly all "noise" trying to do any compression on it, even
the aspects that weren't "pure" white noise, would potentially have
masked the signals. Sonar is all about pulling the signal out of the
noise.


You mean the signal can't be compressed? No way. Any non-random signal
can be compressed to some extent. How much depends on the signal and
the amount of processing power required to compress it. However, in
your example, the processing power to compress the signal would probably
have been greater than that required to process the original signal. So
if there wasn't enough power to process the signal on the ship, there
wouldn't be enough power to compress the near-white noise signal, either.

You really like your all encompassing assumptions. No, all signals can
not be compressed, even non-noise signals can't be compressed if the
signal is not appropriate for the compressor. This is really a very
large topic and I think you are used to dealing with the special cases
without understanding the general case.


Which is just the opposite of what you claimed above. Please make up
your mind.

Try visiting comp.compression and offering them your opinions. There
are many there who are happy to explain the details to you.


I understand the details, thank you. Much better than you do,
obviously. But that's not surprising, either.

You are both talking at cross-purposes. One of you is talking of taking
a sample of white noise and storing it as data. Because of its
statistical properties I would not be surprised if it were impossible to
compress. The other is assuming that by definition noise is not data
and compression would only be usefully applied to a hypothetical signal
added to the white noise, when no properties of the noise would be
relevant for the compressed signal.

I can't think why one should want to record and store a sample of white
noise, but that does not prevent it being used as a hypothetical
example.

I doubt you really have any disagreement, just a misunderstanding.

HTH

--
Roger Hayter

"Brian Reay" wrote in message
...

I went over this at the time, although in connection with another of his
wild claims (he claimed that you couldn't divide complex numbers).
Basically, the mathematical concept, which wasn't Evans' point, of
negative frequency arises from Euler's Identities for sin (theta) and cos
(theta) which leads to the result that a simple, real, sinusoid, is the
sum (using Euler's Identities) of positive and negative terms. In DSP
circles, the negative terms, are generally referred to the 'negative
frequency terms' (or some variation, depending on local usage). These are
generally removed, or filtered (numerically) to simplify the overall
processing task.
If you dig into the archive to the time when Evans first raised this, you
will see he was clearly not referring to 'negative frequency' in terms of
the above. I pointed out his error, although I did under estimate his
lack of understanding and/or ability to twist facts. This is one of the
topics he drags up after a drubbing and he promptly gets another one.

Well, brian, that's another attempt by you to save face by resorting to
rather silly and infantile abusive remarks.

When you grow up, you will realise that there are many different viewpoints
about the phenomena that you discuss that are not wrong just because you
disagree with them (or fail to understand them), and grownups can
disambiguate
the situation by mature and reasonable debate, and not by the nasty
sneering that you adopt for years on end.

How can you ever justify your claim to be assisting newcomers when you
always
sneer at attempts to resolove misunderstandings or promote technical
discussion?

You are your own worse enemy.

"Michael Black" wrote in message
news:alpine.LNX.2.02.1502242300280.13977@darkstar. example.org...
On Tue, 24 Feb 2015, gareth wrote:

What is the point of digital voice when there are already AM, SSB
and FM for those who want to appear indistinguishable from CBers?

Perhaps it is cynicism from the manufacturers who introduce such things
as they see their traditional highly-priced corner of the market
being wiped away by SDR technologies?

Because it's something new, at least to amateur radio.

For the developers, yes, but for the Mongolain Hordes
of CBers-masquerading-as-radio-amateurs, then, no.

"Stephen Thomas Cole" wrote in message
...

You do realise that you're responding to a troll post, right?

There speaks the voice of someone who took 18 years from
first studying for the radio amateur's exam to just getting the
licence targetted at-the-5-year-old.

Is it any wonder that he regards anything that he does not
grasp (ie, anything technical at all) as a troll?

"Stephen Thomas Cole" wrote in message
...

Sadly, Gareth absolutely cannot explain it. He doesn't remotely understand
anything he's talking about, as per.

If you had but the remorest inkling of the technical matters about which
you sneer then you might have some credibility, (although I doubt that
anyone has failed to notice that _ALL_ of your posts are nasty personal
remarks), but as it is, you add weight to the old adage that empty vessels
make the most noise.