[time-nuts] WWVB Response

Dale J. Robertson dale at nap-us.com
Thu Sep 27 12:37:35 UTC 2012


The AM characteristics have not changed. That means that there is at least 
10% carrier present at all times.
The transmission format seems pretty well documented. The remaining 
mysteries are in data formatting.
Regards,
Dale NV8U


-----Original Message----- 
From: Peter Monta
Sent: Thursday, September 27, 2012 1:52 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] WWVB Response

Hi John,

Thank you for clarifying the openness of the transmission format.
Could I ask whether there is any scenario under which aspects of the
signal transmission design might be patented?  If companies or
individuals wish to patent aspects of receiver design, that's fine,
but I'd be uncomfortable with a patent-encumbered transmission format.

> ... It is an unfortunate consequence of improving the reception
> capability of our broadcast that this segment of our loyal user base are 
> so
> adversely affected.  The decision to proceed was not taken lightly, but in
> the end it was decided that the improvement in reception capability
> (especially along the JJY interference prone East Coast) outweighed the 
> loss
> of use of existing PLL devices.

I suppose it's a matter of balancing the value of the PLL receivers
and the loss of BPSK signal power to the residual carrier.  If the
power loss is small, though, say 0.5 dB or below, then given the large
process gains of the advanced receivers, it might be worth
considering.  I don't imagine that the mere presence of residual
carrier has any effect on the advanced receivers (since it is similar
to interference from MSF and JJY, as you say), but please correct me
if I'm wrong.

Cheers,
Peter

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