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K3 Feature Request

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Tim Tucker

K3 Feature Request

For AM users, could we get the ability to invert the voice phase as a
feature of the K3? This would allow us to make sure that the audio phase
orientation is correct where the positive peaks are always greater than the
negative peaks. Even better, it would be cool if the rig could auto detect
an incorrect phase orientation and invert it automatically for us.

Thanks for considering it...
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Jim Brown-10

Re: K3 Feature Request

On 10/5/2010 5:11 PM, Tim Tucker wrote:
> incorrect phase orientation

The correct word to say what you mean is POLARITY, NOT PHASE. Phase is
a continuously valued function, and has the units of degrees. Polarity
is the word that describes whether the waveform is inverted or not.
Changing the phase of a signal is VERY different from changing its
polarity.

What you're asking for is a very good idea. Circuits that sense which
part of the signal is hotter and reverses it if necessary to keep the
hottest part on top (to prevent carrier cutoff) have been around since
at least the 50s.

73, Jim K9YC
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Tim Tucker

Re: K3 Feature Request

OK, thanks for the education. I'm not an RF engineer, but every product on
the market I've come across (doesn't mean much) and discussion I've read
(start with http://www.nu9n.com/am.html) calls what I'm talking about as
phase inversion. They could all be using the wrong term for all I know.

I currently am able to achieve what I'm looking for by using the W2IHY iPlus
in the audio chain driving the K3. You just flip the Invert Phase switch
when you need it. There are Behringer products that do the same thing. You
can SEE the difference it makes on a scope or even a simple AVG reading
power meter when you have correct phase. For example, on an AVG reading
meter, with negative or incorrect phase, you actually see negative
deflection on the meter needle. When you have it correct, you see positive
deflection on the meter needle. It's more obvious on the scope, as pointed
out on NU9N's site. I don't currently have a scope, but I've done the same
tests in the past.

It would be really cool if the K3 could do this too.

On Tue, Oct 5, 2010 at 5:39 PM, Jim Brown <[hidden email]> wrote:

> On 10/5/2010 5:11 PM, Tim Tucker wrote:
> > incorrect phase orientation
>
> The correct word to say what you mean is POLARITY, NOT PHASE. Phase is
> a continuously valued function, and has the units of degrees. Polarity
> is the word that describes whether the waveform is inverted or not.
> Changing the phase of a signal is VERY different from changing its
> polarity.
>
> What you're asking for is a very good idea. Circuits that sense which
> part of the signal is hotter and reverses it if necessary to keep the
> hottest part on top (to prevent carrier cutoff) have been around since
> at least the 50s.
>
> 73, Jim K9YC
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>

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Jim Brown-10

Re: K3 Feature Request

On 10/5/2010 5:58 PM, Tim Tucker wrote:
> OK, thanks for the education. I'm not an RF engineer, but every product on
> the market I've come across (doesn't mean much) and discussion I've read
> (start withhttp://www.nu9n.com/am.html) calls what I'm talking about as
> phase inversion. They could all be using the wrong term for all I know.

Yes, they are. We got educated about that nearly 30 years ago in the pro
audio world, where the difference is also quite important. Many mfrs
(and hams) still haven't gotten the word.

73, Jim K9YC
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Lu Romero - W4LT

Re: K3 Feature Request

In reply to this post by Tim Tucker

Or, he could scour E-Bay for a Kahn Symetra-Peak!

-lu-w4lt-

Message: 37
Date: Tue, 05 Oct 2010 17:39:37 -0700
From: Jim Brown <[hidden email]>
Subject: Re: [Elecraft] K3 Feature Request
To: [hidden email]
Message-ID: <[hidden email]>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

On 10/5/2010 5:11 PM, Tim Tucker wrote:
> incorrect phase orientation

The correct word to say what you mean is POLARITY, NOT PHASE. Phase is
a continuously valued function, and has the units of degrees. Polarity
is the word that describes whether the waveform is inverted or not.
Changing the phase of a signal is VERY different from changing its
polarity.

What you're asking for is a very good idea. Circuits that sense which
part of the signal is hotter and reverses it if necessary to keep the
hottest part on top (to prevent carrier cutoff) have been around since
at least the 50s.

73, Jim K9YC

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Checked by PC Tools AntiVirus (6.1.0.25 - 6.14880).
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Joe Subich, W4TV-4

Re: K3 Feature Request

Or Lyle could simply include the "phase scrambler" (phase rotation)
function in the DSP. IIRC, the Kahn box simply ran the audio through
a filter that caused a frequency dependent phase rotation resulting
in audio that had symmetric positive and negative peaks and avoided
issues with microphone polarity that was voice specific (e.g., one
DJ's voice was "positive dominant" while another was "negative."

73,

... Joe, W4TV

On 10/5/2010 10:41 PM, Luis V. Romero wrote:

> Or, he could scour E-Bay for a Kahn Symetra-Peak!
>
> -lu-w4lt-
>
> Message: 37
> Date: Tue, 05 Oct 2010 17:39:37 -0700
> From: Jim Brown<[hidden email]>
> Subject: Re: [Elecraft] K3 Feature Request
> To: [hidden email]
> Message-ID:<[hidden email]>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> On 10/5/2010 5:11 PM, Tim Tucker wrote:
>> incorrect phase orientation
>
> The correct word to say what you mean is POLARITY, NOT PHASE. Phase is
> a continuously valued function, and has the units of degrees. Polarity
> is the word that describes whether the waveform is inverted or not.
> Changing the phase of a signal is VERY different from changing its
> polarity.
>
> What you're asking for is a very good idea. Circuits that sense which
> part of the signal is hotter and reverses it if necessary to keep the
> hottest part on top (to prevent carrier cutoff) have been around since
> at least the 50s.
>
> 73, Jim K9YC
>

Tim Tucker

Re: K3 Feature Request

Yep, that's exactly what I'm thinking. You either do it automatically or
give the user the ability to switch it themselves. For the UI, it could be
as simple as an additional option in the EQ settings for AM mode (press and
hold 1 to Invert Phase, or something like that...).

I think you guys get the idea. I thought about this because I noticed the
problem on my own station and was able to correct it with the iPlus box and
thought it would be SWEET if it was built into the rig.

On Tue, Oct 5, 2010 at 8:44 PM, Joe Subich, W4TV <[hidden email]> wrote:

>
> Or Lyle could simply include the "phase scrambler" (phase rotation)
> function in the DSP. IIRC, the Kahn box simply ran the audio through
> a filter that caused a frequency dependent phase rotation resulting
> in audio that had symmetric positive and negative peaks and avoided
> issues with microphone polarity that was voice specific (e.g., one
> DJ's voice was "positive dominant" while another was "negative."
>
> 73,
>
> ... Joe, W4TV
>
>
> On 10/5/2010 10:41 PM, Luis V. Romero wrote:
> > Or, he could scour E-Bay for a Kahn Symetra-Peak!
> >
> > -lu-w4lt-
> >
> > Message: 37
> > Date: Tue, 05 Oct 2010 17:39:37 -0700
> > From: Jim Brown<[hidden email]>
> > Subject: Re: [Elecraft] K3 Feature Request
> > To: [hidden email]
> > Message-ID:<[hidden email]>
> > Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> >
> > On 10/5/2010 5:11 PM, Tim Tucker wrote:
> >> incorrect phase orientation
> >
> > The correct word to say what you mean is POLARITY, NOT PHASE. Phase is
> > a continuously valued function, and has the units of degrees. Polarity
> > is the word that describes whether the waveform is inverted or not.
> > Changing the phase of a signal is VERY different from changing its
> > polarity.
> >
> > What you're asking for is a very good idea. Circuits that sense which
> > part of the signal is hotter and reverses it if necessary to keep the
> > hottest part on top (to prevent carrier cutoff) have been around since
> > at least the 50s.
> >
> > 73, Jim K9YC
> >
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>

P.B. Christensen

Re: K3 Feature Request

For each voice, polarity only needs to be set once for each mic source. For
crystal, ceramic, and dynamic mics, that can usually be accomplished by
inverting the polarity at the mic element. Most folks who take AM polarity
seriously are also using some other intermediate audio processing device
with balanced input/output terminations. In that case, inverting polarity
is as easy as flipping conductors on one balanced audio pair. For tiny
electret mics without any additional processing, the problem becomes a bit
more complex to resolve but then, I don't know of many folks using electrets
on AM.

If a phase scrambler were part of the K3's DSP, any thought as to how much
DSP resource utilization is required?

Paul, W9AC.

----- Original Message -----
From: "Tim Tucker" <[hidden email]>
To: <[hidden email]>
Sent: Wednesday, October 06, 2010 12:34 AM
Subject: Re: [Elecraft] K3 Feature Request

> Yep, that's exactly what I'm thinking. You either do it automatically or
> give the user the ability to switch it themselves. For the UI, it could
> be
> as simple as an additional option in the EQ settings for AM mode (press
> and
> hold 1 to Invert Phase, or something like that...).
>
> I think you guys get the idea. I thought about this because I noticed the
> problem on my own station and was able to correct it with the iPlus box
> and
> thought it would be SWEET if it was built into the rig.

George & Jan

Re: K3 Feature Request

Years ago in a land far far away we discontinued using the Semetra-Peak
(sp??) on AM in favor of the then new CBS Labs audio processers (
Audimax/Volumax (sp??)) which did a much better job of increasing the
average modulation with far fewer artifacts.
We did retain the boom mic phase reversal switch for those jocks that
insisted that they sounder louder on reverse. Eventually the switch rusted
in place!

George
AI4VZ
------------------------------------
For each voice, polarity only needs to be set once for each mic source. For
crystal, ceramic, and dynamic mics, that can usually be accomplished by
inverting the polarity at the mic element. donate.html

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Joe Subich, W4TV-4

Re: K3 Feature Request

In reply to this post by P.B. Christensen

Good information on the Symmetra-Peak and phase rotation/scrambling
can be found here: http://www.w3am.com/8poleapf.html and a discussion
of AM symmetry with info on the "all pass filter" (phase rotation)
here: http://www.tonnesoftware.com/appnotes/allpass/allpass.html.

I suspect the rotation would take very few resources to accomplish
in DSP and could be easily accommodated in the TX EQ and/or audio (level
control) portion of the ALC circuits.

73,

... Joe, W4TV

On 10/6/2010 6:04 AM, Paul Christensen wrote:

> For each voice, polarity only needs to be set once for each mic source. For
> crystal, ceramic, and dynamic mics, that can usually be accomplished by
> inverting the polarity at the mic element. Most folks who take AM polarity
> seriously are also using some other intermediate audio processing device
> with balanced input/output terminations. In that case, inverting polarity
> is as easy as flipping conductors on one balanced audio pair. For tiny
> electret mics without any additional processing, the problem becomes a bit
> more complex to resolve but then, I don't know of many folks using electrets
> on AM.
>
> If a phase scrambler were part of the K3's DSP, any thought as to how much
> DSP resource utilization is required?
>
> Paul, W9AC.
>
>

Lu Romero - W4LT

Re: K3 Feature Request

In reply to this post by Tim Tucker

Oh, yes, the vaunted CBS Labs/Thomson CSF Volumax/Audimax
twins! Bob Orban and Frank Foti made a career tweaking
those things. My club has a TV Station Veteran Audimax
(left channel unit) handling the audio from the computer on
a repeater EchoLink VoIP circuit. Not too Ham Friendly, no
blinking lights, just a big edge meter marked green and red
smack dab in the middle... And, it makes a wonderful rack
shelf for the LCD computer monitor, too!

Joe, W4TV, I now know, in retrospect, that I should have
confiscated that Kahn Symetra-Peak that was being used as a
doorstop at the Radio station transmitter site in San
Antonio before Waterman sold the stations for a much higher
calling in Ham Radio!

I coudda been a contendah on 3.625 with that box! :)

-lu-w4lt-

Message: 25
Date: Wed, 6 Oct 2010 09:55:06 -0400
From: "George & Jan" <[hidden email]>
Subject: Re: [Elecraft] K3 Feature Request
To: <[hidden email]>
Message-ID: <0B65D1193114430CA8C66220185D55EE@OfficeDeskTop>
Content-Type: text/plain; charset="iso-8859-1"

Years ago in a land far far away we discontinued using the
Semetra-Peak
(sp??) on AM in favor of the then new CBS Labs audio
processers (
Audimax/Volumax (sp??)) which did a much better job of
increasing the
average modulation with far fewer artifacts.
We did retain the boom mic phase reversal switch for those
jocks that
insisted that they sounder louder on reverse. Eventually the
switch rusted
in place!

George
AI4VZ
------------------------------------
For each voice, polarity only needs to be set once for each
mic source. For
crystal, ceramic, and dynamic mics, that can usually be
accomplished by
inverting the polarity at the mic element.
______________________________________________________________
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Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

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