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Old January 17th 04, 10:06 PM
Pete Beals
 
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Default simple synchronous detector?

Has anyone implemented a simple sync detector that uses as few parts as
possible?

Thanks

Pete
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Old January 18th 04, 08:23 PM
Tim Wescott
 
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I think that "as few parts as possible" and "works good" are probably
somewhat mutually exclusive. Have you done the usual google and altavista
searches on "synchronous detector"?

"Pete Beals" wrote in message
...
Has anyone implemented a simple sync detector that uses as few parts as
possible?

Thanks

Pete



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Old January 19th 04, 05:18 AM
Pete Beals
 
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Default

Yes most used AM stereo demodulators but those IC's might not be sold
anymore.

There must be reasonable implementations as many shortwave receivers have
sync detectors.

I just need one to demodulate AM.


Pete
I think that "as few parts as possible" and "works good" are probably
somewhat mutually exclusive. Have you done the usual google and
altavista searches on "synchronous detector"?

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Old January 19th 04, 03:07 PM
Dale Parfitt
 
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"Pete Beals" wrote in message
...
Yes most used AM stereo demodulators but those IC's might not be sold
anymore.

There must be reasonable implementations as many shortwave receivers have
sync detectors.

I just need one to demodulate AM.


Pete
I think that "as few parts as possible" and "works good" are probably
somewhat mutually exclusive. Have you done the usual google and
altavista searches on "synchronous detector"?


Do a search under KE9OA. Pete is developing a sync detector for use with a
MW RX they are going to market. May possibly sell the sync board separately.
In talking with Pete, and having built my own sync detector- few parts and
sync detectors that stay locked and retrieve hi fi audio do not go together.

Dale W4OP


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Old January 19th 04, 07:47 PM
Jim, N2VX
 
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On Mon, 19 Jan 2004 04:18:19 -0000, Pete Beals
wrote:

Yes most used AM stereo demodulators but those IC's might not be sold
anymore.

There must be reasonable implementations as many shortwave receivers have
sync detectors.

I just need one to demodulate AM.


Pete
I think that "as few parts as possible" and "works good" are probably
somewhat mutually exclusive. Have you done the usual google and
altavista searches on "synchronous detector"?


A long long time ago one appeared in the user-contributed circuits
section of Electronic Design magazine. Don't remember the name of the
column but it was always good. They also used to publish circuit
collections from the column every few years. Lots of clever ideas:
"Build this quadraphonic stereo receiver with a single CMOS interter"
is just a slight exaggeration. I remember reading the magazine up to
the early 90's. Don't know what happened to them.

The synchronous detector used two analog multiplier chips and as I
recall was contributed by someone with a callsign. Don't remember any
other details. Anybody remember the magazine and the column?

Thanks and 73,
Jim


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Old January 20th 04, 12:06 AM
Steve Nosko
 
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Default

This used to be the EDN article search database. It came up, but I don't
know if it still is:
http://www.reed-electronics.com/ednm...=0&rme=0&cfd=1

--
Steve N, K,9;d, c. i My email has no u's.


"Jim, N2VX" wrote in message
...
On Mon, 19 Jan 2004 04:18:19 -0000, Pete Beals
wrote:

Yes most used AM stereo demodulators but those IC's might not be sold
anymore.

There must be reasonable implementations as many shortwave receivers have
sync detectors.

I just need one to demodulate AM.


Pete
I think that "as few parts as possible" and "works good" are probably
somewhat mutually exclusive. Have you done the usual google and
altavista searches on "synchronous detector"?


A long long time ago one appeared in the user-contributed circuits
section of Electronic Design magazine. Don't remember the name of the
column but it was always good. They also used to publish circuit
collections from the column every few years. Lots of clever ideas:
"Build this quadraphonic stereo receiver with a single CMOS interter"
is just a slight exaggeration. I remember reading the magazine up to
the early 90's. Don't know what happened to them.

The synchronous detector used two analog multiplier chips and as I
recall was contributed by someone with a callsign. Don't remember any
other details. Anybody remember the magazine and the column?

Thanks and 73,
Jim



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Old January 20th 04, 12:08 AM
Steve Nosko
 
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Default

What's the essence of an AM sync detector? Extract the carrier
(filter/clip/amplify the bajeebers out of it) then product detect the
sidebands ?
--
Steve N, K,9;d, c. i My email has no u's.

"Jim, N2VX" wrote in message
...
On Mon, 19 Jan 2004 04:18:19 -0000, Pete Beals
wrote:

Yes most used AM stereo demodulators but those IC's might not be sold
anymore.

There must be reasonable implementations as many shortwave receivers have
sync detectors.

I just need one to demodulate AM.


Pete
I think that "as few parts as possible" and "works good" are probably
somewhat mutually exclusive. Have you done the usual google and
altavista searches on "synchronous detector"?


A long long time ago one appeared in the user-contributed circuits
section of Electronic Design magazine. Don't remember the name of the
column but it was always good. They also used to publish circuit
collections from the column every few years. Lots of clever ideas:
"Build this quadraphonic stereo receiver with a single CMOS interter"
is just a slight exaggeration. I remember reading the magazine up to
the early 90's. Don't know what happened to them.

The synchronous detector used two analog multiplier chips and as I
recall was contributed by someone with a callsign. Don't remember any
other details. Anybody remember the magazine and the column?

Thanks and 73,
Jim



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Old January 20th 04, 03:12 AM
Avery Fineman
 
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In article , "Jim, N2VX"
writes:

On Mon, 19 Jan 2004 04:18:19 -0000, Pete Beals
wrote:

Yes most used AM stereo demodulators but those IC's might not be sold
anymore.

There must be reasonable implementations as many shortwave receivers have
sync detectors.

I just need one to demodulate AM.


Pete
I think that "as few parts as possible" and "works good" are probably
somewhat mutually exclusive. Have you done the usual google and
altavista searches on "synchronous detector"?


A long long time ago one appeared in the user-contributed circuits
section of Electronic Design magazine. Don't remember the name of the
column but it was always good. They also used to publish circuit
collections from the column every few years. Lots of clever ideas:
"Build this quadraphonic stereo receiver with a single CMOS interter"
is just a slight exaggeration. I remember reading the magazine up to
the early 90's. Don't know what happened to them.


Electronic Design is online at http://www.elecdesign.com

Their newer website makes it a bit difficult to search for Design
Ideas in past issues. Those probably don't go back farther than
2001 but I could be mistaken. Source code for those column
pieces requiring source is available as separate text files.

EDN is online at http://www.reed-electronics.com/ednmag

EDN's Design Ideas go back only to 1995...but are easier to
access.

The synchronous detector used two analog multiplier chips and as I
recall was contributed by someone with a callsign. Don't remember any
other details. Anybody remember the magazine and the column?


I still get both Electronic Design and EDN, plus RF Design and
Microwaves & RF. Used to cut up the issues after a month or so
and file them for reference...until they all got on-line and I could
write them onto a CD (much easier to reference, less space).

Don't recall the article or didn't bother to log it in memory as
"important." :-) :-(

Motorola quit a whole bunch of specialty ICs a bit ago, very few
showing up on other websites. They made a nice stereo AM IC that
had an automatic synchronous detection system. Not enough
market demand for it. ON Semiconductor still makes a few of the old
Motorola line.

Len Anderson
retired (from regular hours) electronic engineer person
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Old January 20th 04, 04:58 AM
Avery Fineman
 
Posts: n/a
Default

In article , "Steve Nosko"
writes:

What's the essence of an AM sync detector? Extract the carrier
(filter/clip/amplify the bajeebers out of it) then product detect the
sidebands ?
--
Steve N, K,9;d, c. i My email has no u's.


Essentially, yes. There's a further step, though, and that is
locking a local mixing oscillator to the carrier frequency and
mixing that with the whole thing.

If the local mixing oscillator is in phase with the received
carrier, the mixing results in just a DC component which can
be removed easily. A carrier in-phase lock allows separate
detection of the sidebands...which could be used to
advantage such as having binaural audio modulation with AM.

That also works out well for a quasi-stereo listening with any
signal that is NOT binaurally modulated. The effect of hearing
through such a detector's audio cannot accurately be described
in words. Nearby-signal splatter can be "heard" as left or right
of the desired signal. Strange sound but does allow the mind's
own spatial filtering to sort-of blot out nearby interference.

That quasi-stereo circuit is a lot more complicated (it's usually
a typical Costas Loop with local mixing oscillator having shifts
for quadrature phasing) than the direct amplify-limit-clip-the-
bejeebers out of the carrier and mix that with whole works...as
was done in the Motorola MC1330P 8-pin DIP IC (now obsolete
but Kits&Parts as a few left).

Len Anderson
retired (from regular hours) electronic engineer person
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Old January 20th 04, 05:23 PM
Steve Nosko
 
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Default

Steve's imbedded comments:

"Avery Fineman" wrote in message
...
In article , "Steve Nosko"
writes:

What's the essence of an AM sync detector? Extract the carrier
(filter/clip/amplify the bajeebers out of it) then product detect the
sidebands ? Steve N, K,9;d, c. i My email has no u's.


...locking a local mixing oscillator to the carrier frequency and
mixing that with the whole thing.


Ah yes! need a reliable LO.

... A carrier in-phase lock allows separate
detection of the sidebands...which could be used to
advantage such as having binaural audio modulation with AM.


Ah yes... Back to the old three methods of generating / detecting
sideband signals.

Regards, Steve


Lesee if he bites on that....


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