[ntp:questions] Re: Why phase modulation

Rob van der Putten rob at sput.nl
Tue Jan 10 11:51:37 UTC 2006


Hi there


Heiko Gerstung wrote:

>  From our DCF77 info page (http://www.meinberg.de/english/info/dcf77.htm):
> "In order to increase the accuracy of the demodulated time marks, the
> carrier of DCF77 is additionally modulated with a pseudo-random phase
> noise. The pseudo-random sequence has a length of 512 bits which are
> transmitted in the time interval between the AM marks. Due to the
> pseudo-random characteristics of the sequence, the mean deviation of the
> carrier phase is still zero. The phase modulated carrier can be received
> with a larger bandwidth. Correlation algorithms known from satellite
> techniques let PZF receivers determine the correct time with an accuracy
> of some microseconds which is much superior to the accuracy achieved by
> standard AM receivers."

Any more in depth info?

> AFAIK we (Meinberg) are the only vendors offering such a technology. See
> for example:
> 
> NTP Time Server with PZF receiver:
> http://www.meinberg.de/english/products/lanpzf.htm
> 
> Radio Clock Module
> http://www.meinberg.de/english/products/pzf510.htm
> 
> (this one can be ordered as a standalone rack-mountable system with
> power supply and housing)
> 
> and any other products with a "PZF" in their name :-)

Found those.
I was just wondering if there are any more.


Regards,
Rob
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