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HFguy wrote:
AFAIK, There are no HF transceivers with a sync' detector.

I wonder why it is that none of the big three (Kenwood, Icom, Yaesu)
have included synchronous detection circuitry on their HF transceivers.
A lot of these rigs are loaded with all kinds of goodies, right? And
there's the constant competition to put out the ultimate rig... And, I
mean, c'mon, it's not as though these units are used exclusively for
amateur communications... The rx sections are general coverage, after
all...

A few extra goodies to make some of these rigs more suited for AM
broadcast receiving, and these companies could probably tap in to the
SWL market (let's face it, there's not a whole lot of action where new
HF tabletop receivers are concerned...it wouldn't take much for
Icom/Kenwood/Yaesu to get the attention of SWLers...what with all the
IF DSP and spectrum scopes and jazzy multi-colored displays!). And
let's face it, having such a rig on the desk can be quite an inducement
for an SWLer to subsequently go whole hog for the amateur thing...$$$.


Oh, and here's something that the original poster might find
interesting (I know I did):

John Plimmer's comparison of the Drake R8B receiver and the Icom
IC-756ProIII

http://www.dxing.info/equipment/icom_ic756_plimmer.dx

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On 19 Apr 2006 16:15:17 -0700, "junius" wrote:


HFguy wrote:
AFAIK, There are no HF transceivers with a sync' detector.

I wonder why it is that none of the big three (Kenwood, Icom, Yaesu)
have included synchronous detection circuitry on their HF transceivers.

A few extra goodies to make some of these rigs more suited for AM
broadcast receiving, and these companies could probably tap in to the
SWL market (let's face it, there's not a whole lot of action where new
HF tabletop receivers are concerned...it wouldn't take much for
Icom/Kenwood/Yaesu to get the attention of SWLers...what with all the
IF DSP and spectrum scopes and jazzy multi-colored displays!). And
let's face it, having such a rig on the desk can be quite an inducement
for an SWLer to subsequently go whole hog for the amateur thing...$$$.

Maybe because there's no SWLers left...

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In article . com,
"junius" wrote:


HFguy wrote:
AFAIK, There are no HF transceivers with a sync' detector.

I wonder why it is that none of the big three (Kenwood, Icom, Yaesu)
have included synchronous detection circuitry on their HF
transceivers. A lot of these rigs are loaded with all kinds of
goodies, right? And there's the constant competition to put out the
ultimate rig... And, I mean, c'mon, it's not as though these units
are used exclusively for amateur communications... The rx sections
are general coverage, after all...

Snip

Most ham voice communications are SSB where you would not use sync
detection. A few ham operators use AM mode and it would help there I
guess but the percentage using AM is small by comparison.

--
Telamon
Ventura, California

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junius wrote:
HFguy wrote:

AFAIK, There are no HF transceivers with a sync' detector.


I wonder why it is that none of the big three (Kenwood, Icom, Yaesu)
have included synchronous detection circuitry on their HF transceivers.

Because ham's use mostly SSB on the HF bands. A sync' detector is not
useful for that mode.

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HFguy wrote:


Because ham's use mostly SSB on the HF bands. A sync' detector is not
useful for that mode.

Sure, I realize and appreciate that. But as I said earlier, these
transceivers have a general coverage receiver section...it's not as
though amateur communications is of any account, for instance, in the
MW BCB or the int'l SW BCBs. Through these online fora, it's apparent
that a significant number of radio amateurs have an interest in the
reception of signals in these bands. Moreover, how much of a further
investment would be required to give a transceiver a greater edge in
this area? From what I can see, this might be done simply with the
addition of AM Sync detector circuitry and the expansion of the DSP
variable bandwidth control from the SSB range on up to 6.0 kHz or so.
The technology already there, so...

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junius wrote:
HFguy wrote:


Because ham's use mostly SSB on the HF bands. A sync' detector is not
useful for that mode.


Sure, I realize and appreciate that. But as I said earlier, these
transceivers have a general coverage receiver section...it's not as
though amateur communications is of any account, for instance, in the
MW BCB or the int'l SW BCBs. Through these online fora, it's apparent
that a significant number of radio amateurs have an interest in the
reception of signals in these bands. Moreover, how much of a further
investment would be required to give a transceiver a greater edge in
this area? From what I can see, this might be done simply with the
addition of AM Sync detector circuitry and the expansion of the DSP
variable bandwidth control from the SSB range on up to 6.0 kHz or so.
The technology already there, so...

Although it doesn't cost that much these days to extend the range of an
HF-transceiver for general coverage, it could be harder to come up with
a good sync' detector that doesn't infringe on another manufacturers
design. Look what happened to the R-75. I'm sure Icom knows how to
design a good sync' detector but there may have been legal limitations
to what they could implement. This could be the main reason the
manufacturers are not interested in adding a sync' detector to a general
coverage HF-transceiver. I also don't think it's really so "apparent
that a significant number of radio amateurs have an interest" in
listening to international shortwave broadcasts. It's been my experience
that few do.

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On Fri, 21 Apr 2006 10:14:43 GMT, HFguy wrote:


Although it doesn't cost that much these days to extend the range of an
HF-transceiver for general coverage, it could be harder to come up with
a good sync' detector that doesn't infringe on another manufacturers
design. Look what happened to the R-75. I'm sure Icom knows how to
design a good sync' detector but there may have been legal limitations
to what they could implement. This could be the main reason the
manufacturers are not interested in adding a sync' detector to a general
coverage HF-transceiver. I also don't think it's really so "apparent
that a significant number of radio amateurs have an interest" in
listening to international shortwave broadcasts. It's been my experience
that few do.

Synchronous detection is old enough to be in the public domain.

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"HFguy" wrote in message
news:ng22g.739$5z3.735@trndny01...
junius wrote:

Although it doesn't cost that much these days to extend the range of an
HF-transceiver for general coverage, it could be harder to come up with
a good sync' detector that doesn't infringe on another manufacturers
design. Look what happened to the R-75. I'm sure Icom knows how to
design a good sync' detector but there may have been legal limitations
to what they could implement. This could be the main reason the
manufacturers are not interested in adding a sync' detector to a general
coverage HF-transceiver.

That's an interesting point, but I think Drake is licensing their sync
detector and I suppose other manufacturers would also license theirs, if
they think it wouldn't take away too many of their own radio sales. That's
assuming that's there's still much worth licensing. Most of those patents
must have been around a while.

Chip fabrication is another issue. ASICs are economical only in large runs.
Motorola used sync detection in it's AM stereo chipset, and I'd guess
adapting it to a stand alone sync detector would be easy enough. They must
have not thought there was enough buyers to bother with.


I also don't think it's really so "apparent
that a significant number of radio amateurs have an interest" in
listening to international shortwave broadcasts. It's been my experience
that few do.

Speaking only as an occasional hamfest attendee, I've noticed little interst
there concerning international broadcasting even though these guys are very
much SW radio hobbyists.

Frank Dresser

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In article ng22g.739$5z3.735@trndny01, HFguy
wrote:

junius wrote:
HFguy wrote:


Because ham's use mostly SSB on the HF bands. A sync' detector is not
useful for that mode.


Sure, I realize and appreciate that. But as I said earlier, these
transceivers have a general coverage receiver section...it's not as
though amateur communications is of any account, for instance, in the
MW BCB or the int'l SW BCBs. Through these online fora, it's apparent
that a significant number of radio amateurs have an interest in the
reception of signals in these bands. Moreover, how much of a further
investment would be required to give a transceiver a greater edge in
this area? From what I can see, this might be done simply with the
addition of AM Sync detector circuitry and the expansion of the DSP
variable bandwidth control from the SSB range on up to 6.0 kHz or so.
The technology already there, so...

Although it doesn't cost that much these days to extend the range of an
HF-transceiver for general coverage, it could be harder to come up with
a good sync' detector that doesn't infringe on another manufacturers
design. Look what happened to the R-75. I'm sure Icom knows how to
design a good sync' detector but there may have been legal limitations
to what they could implement. This could be the main reason the
manufacturers are not interested in adding a sync' detector to a general
coverage HF-transceiver. I also don't think it's really so "apparent
that a significant number of radio amateurs have an interest" in
listening to international shortwave broadcasts. It's been my experience
that few do.

Are you sure about the patent cost? I thought sync detection was mostly
implemented through a PLL type circuit. You can buy this circuit on a
chip with a handful of support components for it to function. Maybe you
have to add a reference oscillator to the circuit with the other support
components. Anyone should be able to buy and use these designs.

--
Telamon
Ventura, California

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On Fri, 21 Apr 2006 21:54:39 GMT, Telamon
wrote:

In article ng22g.739$5z3.735@trndny01, HFguy
wrote:

Are you sure about the patent cost? I thought sync detection was mostly
implemented through a PLL type circuit. You can buy this circuit on a
chip with a handful of support components for it to function. Maybe you
have to add a reference oscillator to the circuit with the other support
components. Anyone should be able to buy and use these designs.

A PLL and a Product Detector

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David wrote:
wrote:
Are you sure about the patent cost? I thought sync detection was mostly
implemented through a PLL type circuit.

A PLL and a Product Detector

You can do without the PLL, too. You just create the signal with a
separate stage that overamplifies the signal into clipping, then
you have basically a sorta-square wave to feed into the product
detector.

--
All relevant people are pertinent.
All rude people are impertinent.
Therefore, no rude people are relevant.
-- Solomon W. Golomb

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On Fri, 21 Apr 2006 17:46:36 -0500, clifto wrote:

David wrote:
wrote:
Are you sure about the patent cost? I thought sync detection was mostly
implemented through a PLL type circuit.

A PLL and a Product Detector

You can do without the PLL, too. You just create the signal with a
separate stage that overamplifies the signal into clipping, then
you have basically a sorta-square wave to feed into the product
detector.

Does that work when the station carrier fades?

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"David" wrote in message
...
On Fri, 21 Apr 2006 17:46:36 -0500, clifto wrote:

David wrote:
wrote:
Are you sure about the patent cost? I thought sync detection was mostly
implemented through a PLL type circuit.

A PLL and a Product Detector

You can do without the PLL, too. You just create the signal with a
separate stage that overamplifies the signal into clipping, then
you have basically a sorta-square wave to feed into the product
detector.

Does that work when the station carrier fades?

Not as well in deep fades as a 'truly' synchronous detector. That's often
called a 'quasi-synchronous' detector since there is not a synchronised
oscillator, just the amplified carrier, mixed with the signal in the product
detector.

Tom

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David wrote:
On Fri, 21 Apr 2006 17:46:36 -0500, clifto wrote:
David wrote:
wrote:
Are you sure about the patent cost? I thought sync detection was mostly
implemented through a PLL type circuit.

A PLL and a Product Detector

You can do without the PLL, too. You just create the signal with a
separate stage that overamplifies the signal into clipping, then
you have basically a sorta-square wave to feed into the product
detector.

Does that work when the station carrier fades?

I've wondered the same thing. But there apparently are receivers
using that technique.
http://www.radio-electronics.com/info/receivers/synchdet/sync_det.php
describes the principle; see especially the diagram captioned
"A synchronous detector using a high gain-limiting amplifier
to extract the carrier".

--
All relevant people are pertinent.
All rude people are impertinent.
Therefore, no rude people are relevant.
-- Solomon W. Golomb

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On Sat, 22 Apr 2006 01:44:27 -0500, clifto wrote:

David wrote:
On Fri, 21 Apr 2006 17:46:36 -0500, clifto wrote:
David wrote:
wrote:
Are you sure about the patent cost? I thought sync detection was mostly
implemented through a PLL type circuit.

A PLL and a Product Detector

You can do without the PLL, too. You just create the signal with a
separate stage that overamplifies the signal into clipping, then
you have basically a sorta-square wave to feed into the product
detector.

Does that work when the station carrier fades?

I've wondered the same thing. But there apparently are receivers
using that technique.
http://www.radio-electronics.com/info/receivers/synchdet/sync_det.php
describes the principle; see especially the diagram captioned
"A synchronous detector using a high gain-limiting amplifier
to extract the carrier".
The extracted carrier should be used to lock a locally generated
carrier, with sufficient hysteresis to free run accurately during
selective fades.

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clifto wrote:
David wrote:

wrote:

Are you sure about the patent cost? I thought sync detection was mostly
implemented through a PLL type circuit.

A PLL and a Product Detector


You can do without the PLL, too. You just create the signal with a
separate stage that overamplifies the signal into clipping, then
you have basically a sorta-square wave to feed into the product
detector.

That's the poor man's sync' detector. It works but it's no match for
using a PLL with sideband phase cancellation. That's what made the Drake
system so good.