r8 vs. r8a
 

Michael Black wrote:
And one reality is that "sync detectors" came into common use in relatively
low end receivers. Before the Sony 2010, I can't think of any receiver
that had a built in sync detector. The advantage in that and other low
end receivers is that it does allow "narrowing" the selectivity without
the cost of a filter. It is cheaper to use some passive components and
an IC than to add a good IF filter.

The "sync" detector of the ICF-2010 was originaly a gimmick. Sony took the old,
tired, IFC-2001 design, clean it up, improved the reception and microprocessor,
added air band, but still needed something to really make the radio different
than the other 2001 derived radios which were coming onto the market.

By the time they were designing it, AM stereo was a commercial failure in
the U.S. Sony had a warehouse full of custom AM decoder chips and no where
to put them. One of their engineers figured out how to convert them to
a sync detector and put it in the 2010.

It was a great success.

Geoff.
--
Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM
IL Voice: (07)-7424-1667 Fax ONLY: 972-2-648-1443 U.S. Voice: 1-215-821-1838
Visit my 'blog at http://geoffstechno.livejournal.com/

r8 vs. r8a
 

Geoffrey S. Mendelson wrote:

Michael Black wrote:
And one reality is that "sync detectors" came into common use in
relatively
low end receivers. Before the Sony 2010, I can't think of any receiver
that had a built in sync detector. The advantage in that and other low
end receivers is that it does allow "narrowing" the selectivity without
the cost of a filter. It is cheaper to use some passive components and
an IC than to add a good IF filter.

The "sync" detector of the ICF-2010 was originaly a gimmick. Sony took the
old, tired, IFC-2001 design, clean it up, improved the reception and
microprocessor, added air band, but still needed something to really make
the radio different than the other 2001 derived radios which were coming
onto the market.

By the time they were designing it, AM stereo was a commercial failure in
the U.S. Sony had a warehouse full of custom AM decoder chips and no where
to put them. One of their engineers figured out how to convert them to
a sync detector and put it in the 2010.

It was a great success.

Geoff.


It probably wasn't hard to convert as the Kahn-Hazeltine method was ISB.

From: http://en.wikipedia.org/wiki/AM_stereo

"The Kahn-Hazeltine system worked on an entirely different principle which
independently modulated the upper and lower sidebands separately to
differentiate the difference in program material. If an AM station were
broadcasting AM stereo using the Kahn system, stereophonic sound could be
partially enjoyed by tuning two standard radios slightly to either side of
the station, one to the right side of best tune and one to the left of best
tune. The best way to experience the most stereo separation however was by
using an AM Stereo tuner with appropriate circuitry for decoding the Kahn
system."

Just set the decoder to the mode and pick the left or right output.

r8 vs. r8a
 

Thanks Telamon. That is how I thought it worked.

73, Ken

Telamon wrote:
In article . com,
"Ken Wilson" wrote:

With PBT, the ability to attenuate the unwanted sideband is limited by the
skirt selectivity characteristics of the filter.

With selectable sideband sync detectors, the unwanted sideband is cancelled
by the circuitry. This can be significant if the detector is well tuned.

The two are not the same.

OK Thanks for the Info.

When the unwanted sideband is cancelled by the circuitry how do you get
the 6khz bandwidth instead of 3khz.Or maybe you don't ????

I am talking/asking about the Drake R8A vs R8B receivers only... with
the bandwidth set to 6khz & AM SYNC mode.

Learning all the time.

In AM mode, listening to an AM station and with the PBT control at 12
o'clock using the 6KHz filter you have 3 KHz of the lower and 3KHz of
the upper side bands. Rotate the PBT control to 3 o'clock and you have 6
KHz of the upper side band and none of the lower side band. You get the
reverse situation when you turn the PBT to 9 o'clock.

The high modulated frequencies are farther from the carrier so you will
hear an improvement in the audio high end when the PBT control is turned
either way from the 12 o'clock position.

--
Telamon
Ventura, California