Hi, Rob:
Rob van der Putten wrote:
Hi there
Why does DCF77's phase modulation (DCFp) offer a more reliable timing then
AM?
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."
Who produces these recievers and what do they cost?
Is GPS better or cheaper then DCFp?
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 :-)
Regards,
Rob
Kind regards,
Heiko
_______________________________________________
questions mailing list
[email protected]
https://lists.ntp.isc.org/mailman/listinfo/questions
