In article ,
"Frank Dresser" wrote:

"David Eduardo" wrote in message
...

[snip]


No, most people don't realize there is no stereo separation because the
lit
stereo light convinces them it is stereo when it is not.

[snip]

Let's not forget about modern FM car radios. My car's radio blends from
stereo to mono quite seamlessly as signals become less than ideal. If I pay
attention, I'll notice that the reception is in weak stereo or full mono
much of the time. That's preferable because there's practially no distorted
audio, abrupt switches from stereo to mono and picket fencing that come with
full time stereo car radios. All the while, the stereo light never blinks
off.

The stereo indicator only lights when a 19KHz pilot carrier is present.
The program material could be monophonic or stereo.

--
Telamon
Ventura, California

"Telamon" wrote in message
...
In article ,
"Frank Dresser" wrote:

"David Eduardo" wrote in message
...

[snip]


No, most people don't realize there is no stereo separation because
the
lit
stereo light convinces them it is stereo when it is not.

[snip]

Let's not forget about modern FM car radios. My car's radio blends from
stereo to mono quite seamlessly as signals become less than ideal. If I
pay
attention, I'll notice that the reception is in weak stereo or full mono
much of the time. That's preferable because there's practially no
distorted
audio, abrupt switches from stereo to mono and picket fencing that come
with
full time stereo car radios. All the while, the stereo light never
blinks
off.

The stereo indicator only lights when a 19KHz pilot carrier is present.
The program material could be monophonic or stereo.


Yes, but the stereo demodulator blends to mono as the signal weakens. Mono
demodulation needs far less signal to get a good signal to noise radio. And
this isn't the stereo to mono auto switching the older demodulators used,
it's a gradual blend without an abrupt shift. The system works quite well
and I'm sure much of the time it's working as a mono demodulator on weak
signal stereo programming. There isn't even a stereo-mono switch on the
radio. It doesn't need one.

Frank Dresser

In article ,
"Frank Dresser" wrote:

"Telamon" wrote in message
...
In article ,
"Frank Dresser" wrote:

"David Eduardo" wrote in message
...

[snip]


No, most people don't realize there is no stereo separation because
the
lit
stereo light convinces them it is stereo when it is not.

[snip]

Let's not forget about modern FM car radios. My car's radio blends from
stereo to mono quite seamlessly as signals become less than ideal. If I
pay
attention, I'll notice that the reception is in weak stereo or full mono
much of the time. That's preferable because there's practially no
distorted
audio, abrupt switches from stereo to mono and picket fencing that come
with
full time stereo car radios. All the while, the stereo light never
blinks
off.

The stereo indicator only lights when a 19KHz pilot carrier is present.
The program material could be monophonic or stereo.


Yes, but the stereo demodulator blends to mono as the signal weakens. Mono
demodulation needs far less signal to get a good signal to noise radio. And
this isn't the stereo to mono auto switching the older demodulators used,
it's a gradual blend without an abrupt shift. The system works quite well
and I'm sure much of the time it's working as a mono demodulator on weak
signal stereo programming. There isn't even a stereo-mono switch on the
radio. It doesn't need one.

I haven't kept up with developments. How is this blending accomplished?
Maybe you could point me toward someone's FM demodulator chip.

--
Telamon
Ventura, California

"Telamon" wrote in message
...

I haven't kept up with developments. How is this blending accomplished?
Maybe you could point me toward someone's FM demodulator chip.


I believe the troublesome L-R signal is AGC controlled. Strong signal
reception gets full L-R which gets reduced with decreasing signal strength,
while the L+R signal remains at full strength with all signal levels.

Anyway, here's one chip:

http://eshop.engineering.uiowa.edu/N...9/DS007973.pdf


Frank Dresser

In article ,
"Frank Dresser" wrote:

"Telamon" wrote in message
...

I haven't kept up with developments. How is this blending accomplished?
Maybe you could point me toward someone's FM demodulator chip.


I believe the troublesome L-R signal is AGC controlled. Strong signal
reception gets full L-R which gets reduced with decreasing signal strength,
while the L+R signal remains at full strength with all signal levels.

Anyway, here's one chip:

http://eshop.engineering.uiowa.edu/N...9/DS007973.pdf

I see page 7 has a curve showing 0 to just over 50 dB of separation.

The chip was released back in 1987, interesting.

--
Telamon
Ventura, California