[Boatanchors] Independent sideband suppressed-carrier

[Gary Schafer]

> -----Original Message-----
> From: Boatanchors [mailto:boatanchors-bounces at mailman.qth.net] On Behalf
> Of Chris Trask
> Sent: Monday, October 20, 2014 12:54 PM
> To: Gary Schafer; 'rbethman'; boatanchors at mailman.qth.net
> Subject: Re: [Boatanchors] Independent sideband suppressed-carrier
> 
> >
> >The disadvantage in either the Costas or the pilot carrier method is
> the
> >rather complex receiver.
> >With the Costas loop, Interference on one side of the signal can upset
> the
> >phase lock.
> >It can not be used as an independent side band signal.
> >
> 
>      Not necessrily.  If the pilot tone is injected into both sidebands
> the Costas Loop will lock onto that as it will be coherent while seeing
> the independent sidebands as incoherent noise.  After the post-detection
> quadrature phase shifter the two outputs are summed and differenced in
> separate channels, yielding the two sidebands independently.
> 
>      It only requires that the pilot tone be included in the transmitter
> and an additional summation (or differencing) stage be added to the
> receiver.
> 
>      I devised one of these decades ago to send both SSTV and audio
> simultaneously.  The proper term for such a system is "vestigial (sp?)
> sideband".
> 
> 
> Chris Trask
> N7ZWY / WDX3HLB

When I mentioned "pilot carrier" I was speaking about a small carrier on the
original carrier frequency. But yes I agree that a pilot tone would work as
you describe providing a reference.

73
Gary K4FMX