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Re: [ARSCLIST] Stereo records.
On 17/06/06, Mike Richter wrote:
> Don Cox wrote of AM/FM Stereo
>
>> It might have worked better with the sum on one channel and the
>> difference on the other - then they don't have to be matched.
>>
>> But that would need a decoder of some kind. Just a passive network, I
>> think.
>
> I believe you're operating in another world of electronics, not the
> one which existed in that era. In that period - the late 50s before
> the multiplex standard was established - we were told to put the AM
> radio a few feet from the FM radio to get stereo. No wiring needed at
> all except to the power line (mains).
>
> In practice, sum-and-difference would have been better only in that
> the loss of highs would be balanced on the two sides. Presumably, AM
> would be the difference signal, so it is easy to see that separation
> in the midrange would be largely defeated by the absence of separation
> in the highs.
I was thinking that FM would be the difference signal.
> At any rate, AM/FM stereo was an experiment that was clearly doomed
> from the start. There was also an attempt using two FM stations which
> had little chance from the beginning given the value of bandwidth even
> then. Multiplex isn't a very good choice for fidelity, but it is
> practical and that's what counts.
Actually the sound quality from BBC FM broadcasts used to be excellent.
It may still be, but I don't currently have a rooftop aerial to check.
Regards
--
Don Cox
doncox@xxxxxxxxxxxxxx