Re: OPT equalising circuit

In article <688enrF2s54p5U1@[EMAIL PROTECTED]
>,
 "Phil Allison" <philallison@[EMAIL PROTECTED]
> wrote:

> "Alex"
> >
> > May I ask you, Partick, which AM radio station has the least
distortion? I
> > live in Sydney, and I wold say, BBC (around 600KHz) is the best.
> 
> ** The  BBC   ???????
> 
> Not here in bloody Aussie  -   maaaaaateee.
> 
> Surely you mean  " ABC  Radio National"  on 576 kHz.
> 
> > Others use
> > some elaborate compression and clipping which makes one's ears tired
very
> > soon.
> 
> **   Yaaaawwwnnnnn ...
> 
> > Do the stations INDEED transmit 18KHz of bandwidth?
> 
> **  No   -   but the recovered audio bandwidth derived from ABC Radio 
> National here in Sydney exceeds 10 kHz for sure.
> 
> I own a valve, Aussie made Hi-Fi AM tuner with 15 kHz ( -3dB)  bandwidth

> able to prove that anytime  - the Audiosound AM100.
> 
> > With only 9KHz grid?
> 
> ** Not relevant in this country pal -   with its huge distances between
all 
> the major cities.
> 
> That one fact alone allows Australia to have the highest audio quality
AM 
> radio in the world  -  or we did until about 20 years ago when AM 
> broadcasters all turned to brainless " talkback " programming.
> 
> Peeeeeuuukee....
> 
> > On the stereo-decoder note, what is the phasing of 19KHz pilot with 
> > respect
> > to the 38KHz (suppressed) carrier: do the zero-crossings coinside
(every
> > second one) or peaks coinside (every secon ones)?
> 
> ** A moot point  -  I would have thought.
> 
> Like " ... is the glass half empty or half full ??  "

It's hardly a moot point, if you adjust it so the peaks coincide the 
glass will always be totally empty and you will never get any stereo 
separation.  The ideal adjustment is where the zero crossings coincide, 
although some error here can be corrected by a compensating adjustment 
in the matrix, however the signal/noise ratio will suffer.


Regards,

John Byrns

-- 
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