A sync detector does not have to be a sideband-selectable type to be
a what
would be referred to as a true type of sync detector. It does need to
be a
PLL type, though.

Pete

This is true, of course, but a sync. detector in modern equipment that
is not sideband-selectable
for the SW environment, where there's often so much adjacent channel
interference, is a perversity.

RK

rkhalona wrote:

A sync detector does not have to be a sideband-selectable type to be
a what
would be referred to as a true type of sync detector. It does need to
be a
PLL type, though.

Pete

This is true, of course, but a sync. detector in modern equipment that
is not sideband-selectable
for the SW environment, where there's often so much adjacent channel
interference, is a perversity.

You're a 'newbie'... right?

My oh my, what did one ever do without 'synch'.

dxAce
Michigan
USA

dxAce wrote:

You're a 'newbie'... right?

LOL! If you only knew...

RK

rkhalona wrote:

dxAce wrote:

You're a 'newbie'... right?

LOL! If you only knew...

So tell me, tell us... No need to be a poseur.

dxAce
Michigan
USA

I've been a SWLer for at least 20 years, have a Ph.D. in EE, have 20+
years of
experience in the telecomm industry (uwave, sats, cellular, UWB...) and
have taught
grad/undergrad comm courses at various U.S. universities.

I agree with another poster that the SW8/R8B sync. detectors are among
the best ever incorporated
into SWL gear. My previous comment about sync. doesn't mean that one
cannot achieve similar
signall quality without it (e.g., using PBT, but how many portables or
low-cost tabletops have PBT
these days?), but the convenience of being able to select sidebands in
sync mode is a big plus.

RK

rkhalona wrote:

I've been a SWLer for at least 20 years, have a Ph.D. in EE, have 20+
years of
experience in the telecomm industry (uwave, sats, cellular, UWB...) and
have taught
grad/undergrad comm courses at various U.S. universities.

I agree with another poster that the SW8/R8B sync. detectors are among
the best ever incorporated
into SWL gear. My previous comment about sync. doesn't mean that one
cannot achieve similar
signall quality without it (e.g., using PBT, but how many portables or
low-cost tabletops have PBT
these days?), but the convenience of being able to select sidebands in
sync mode is a big plus.

Yep... a newbie.

dxAce
Michigan
USA

"rkhalona" ) writes:
I've been a SWLer for at least 20 years, have a Ph.D. in EE, have 20+
years of
experience in the telecomm industry (uwave, sats, cellular, UWB...) and
have taught
grad/undergrad comm courses at various U.S. universities.

I agree with another poster that the SW8/R8B sync. detectors are among
the best ever incorporated
into SWL gear. My previous comment about sync. doesn't mean that one
cannot achieve similar
signall quality without it (e.g., using PBT, but how many portables or
low-cost tabletops have PBT
these days?), but the convenience of being able to select sidebands in
sync mode is a big plus.

RK

But it seems you are mixing apples and oranges.

Sync detection means a locally generated "carrier" is present, so
if the signal fades the lack of a strong carrier is not a factor.

It does nothing to prevent fading (which I bring up because someone
recently said something along those lines here) it merely helps when
the signal fades.

Selectable sideband really has nothing to do with synchronous
detection, other than that using the phasing method it's relatively
cheap to implement compared to an expensive IF filter. It's not
really like a few extra parts to a synchronous detector will
add selective sideband, the added parts may be cheap but it adds
complication to the circuit.

When Webb wrote about the synchronous detector in CQ Magazine
about it, it was the whole shebang. But, that was a time
when many receivers had fairly wide IF filters, and lacked
product detectors. At the same time, you'd see SSB adaptors
that used the phasing method, which added that product
detector and reduced the unwanted sideband. Adding
synchronous circuitry to those was relatively simple, so once
you added the sync circuitry you not only got DSBsc reception,
but better SSB reception.

What we often see is lower end receivers tossing it in (because
the phasing method is a cheap way of knocking out the unwanted
sideband, and plus there are ICs that do it all in one
package), but it doesn't make up for the lack of a narrow
IF filter with steep sides (at least not as implemented
in those cheap receivers). It's a means of adding something
without a major cost increase.

I'm not even sure where we've veered off to. I thought
the previous comment was something like synchronous detection
wasn't all that important. I'd say that's true, given that
people lived without it till it became a feature in relatively
recent years. Someone listening to broadcast radio (am or
shortwave) that are relatively strong may be the ones to
benefit the most, because you can get deep fades where
the sidebands are still nice and strong. Signals
that you have to strain to hear, it's far less likely to
be useful, because they are already below a minimum strength.
You'd want to pull in other techniques at that point, and that
includes the narrow IF filter that has good slopes.

Michael

In article .com,
"rkhalona" wrote:

I've been a SWLer for at least 20 years, have a Ph.D. in EE, have 20+
years of experience in the telecomm industry (uwave, sats, cellular,
UWB...) and have taught grad/undergrad comm courses at various U.S.
universities.

I agree with another poster that the SW8/R8B sync. detectors are
among the best ever incorporated into SWL gear. My previous comment
about sync. doesn't mean that one cannot achieve similar signall
quality without it (e.g., using PBT, but how many portables or
low-cost tabletops have PBT these days?), but the convenience of
being able to select sidebands in sync mode is a big plus.

This news group has more than it's share of Ph.D.'s and double E's it
seems.

Where do you think the future of telecom is going? Is it going to be
mostly fiber-optic or do you think RF for the last mile to the home or
business?

Do you think Ethernet is winning over ATM?

--
Telamon
Ventura, California

True........most people are looking for that characteristic.

Pete

"rkhalona" wrote in message
oups.com...
A sync detector does not have to be a sideband-selectable type to be
a what
would be referred to as a true type of sync detector. It does need to
be a
PLL type, though.

Pete

This is true, of course, but a sync. detector in modern equipment that
is not sideband-selectable
for the SW environment, where there's often so much adjacent channel
interference, is a perversity.

RK

In article .com,
rkhalona wrote:
A sync detector does not have to be a sideband-selectable type to be
a what
would be referred to as a true type of sync detector. It does need to
be a
PLL type, though.

Pete

This is true, of course, but a sync. detector in modern equipment that
is not sideband-selectable
for the SW environment, where there's often so much adjacent channel
interference, is a perversity.

Why is using an I/Q "Image reject" mixer better than just having a
narrower filter? As I understand it, you're not going to get more
than 50 dB rejection with an image reject mixer.

Mark Zenier Washington State resident