[ICOM] Bad TX audio on 775

[D C *Mac* Macdonald]

And, as compandering is to amplitude as Dolby Noise
Reduction is to frequency.  High frequency components
are progressively emphasized prior being sent to the
recording heads and then de-emphasized for playback to
enhance the overall signal-to-noise ratio on tape systems.
This boosts the recorded signal energy in relation to a
fixed level of hiss making for higher "fi" to the listener.

Of course, the young sprouts with their CDs and iPods
and MP3 know nothing of this problem from the past!!

(;-p)

Mac - K2GKK/5


----Original Message Follows----
From: Bob Kulow <kulow at epix.net>
Reply-To: ICOM Reflector <icom at mailman.qth.net>
To: ICOM Reflector <icom at mailman.qth.net>
Subject: Re: [ICOM] Bad TX audio on 775
Date: Sun, 15 Oct 2006 14:01:49 -0400


><snip>

>Compandering is a completely different ball game. To use compandering, the 
>'normal' 300 to 3000 Hz audio frequencies are 'converted' to different 
>frequencies and then transmitted (over a narrower bandwidth channel). At 
>the other end, the received signal is un-compandered and converted back to 
>it's original 300 to 3KHz communications quality audio. For 
>instance.........

This may be a new form of compandering, but the "classic" definition of 
compandering is compression at the transmitting end followed by 
complementary expansion at the receiving end to restore the dynamic range 
that was lost in compression (Compander: COMPressor AND exPANDER).  This was 
used in many of the Bell System analog carrier systems to improve SNR.

73
Bob WA2UEH