SERTEL T-GPS-300, Operation Manual

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40.
SERTEL DCF 77 Introduction
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DCF time code (slow code, 1 bit/sec.)
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Minute pulses (time marks)
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Hour pulses (optional time marks, 1 second duration).
The time information corresponds to local time (UTC + programmed time shift).
DCF time code :
The DCF time code (as transmitted by the German DCF77 transmitter on 77.5 kHz) is a slow
serial time code consisting of 60 bits, transmitted at the rate of 1 bit/s. It takes 1 minute to
deliver the full code. This time code is handy for many types of applications and it is becoming
widely-used in Europe. The coding is as follows :
Bit rate : 1 bit/sec. Negative pulses, beginning on the second (open collector starts
conducting).
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Pulse duration 0.1 second = value "0"
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Pulse duration 0.2 second = value "1"
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No pulse at second 59 of every minute (---> minute identifier !)