On Tue, 20 Mar 2018 21:16:11 +0100, Andreas Mattheiss wrote: > Hello, > > I'm monkeying around with raw DCF again ... > > I have slightly modified a DCF77 alarm clock so that it constantly > receives the DCF77 signal and tapped into the 100/200ms pulses. Receiption > must be good, since when I pipe this into an Arduino board I get good > results from the decode. For the PC, I first inverted the 100/200ms pulses > with a transistor, then feed the inverted signal into a MAX232 level > converter - inverting is necessary since the MAX232 inverts the CMOS level > signal itself. The MAX232 has a LED at the output that now duly shows > 100 and 200ms flashes - i.e. it is out most of the time. Hook up to ttyS2. > > So far, so good. Alas I only get crap: > > 20 Mar 20:59:53 ntpd[15775]: parse: convert_rawdcf: start bit / parity check > FAILED for "###############RADMLS1248124P124812P1248121241248112481248P??" > 20 Mar 20:59:53 ntpd[15775]: parse: convert_rawdcf: start bit / parity check > FAILED for "###############RADMLS1248124P124812P1248121241248112481248P??" > 20 Mar 20:59:54 ntpd[15775]: parse: convert_rawdcf: start bit / parity check > FAILED for "###############RADMLS1248124P124812P1248121241248112481248P??" > 20 Mar 20:59:54 ntpd[15775]: parse: convert_rawdcf: start bit / parity check > FAILED for "###############RADMLS1248124P124812P1248121241248112481248P??" > 20 Mar 20:59:54 ntpd[15775]: parse: convert_rawdcf: start bit / parity check > FAILED for "###############RADMLS1248124P124812P1248121241248112481248P??" > 20 Mar 20:59:54 ntpd[15775]: parse: convert_rawdcf: start bit / parity check > FAILED for "###############RADMLS1248124P124812P1248121241248112481248P??" > 20 Mar 21:00:00 ntpd[15775]: parse: convert_rawdcf: start bit / parity check > FAILED for "###############RADMLS1248124P124812P124812124124811248----" > 20 Mar 21:00:03 ntpd[15775]: parse: convert_rawdcf: start bit / parity check > FAILED for "#--############RADMLS1248124P124812P1248121241248112481248P??" > 20 Mar 21:00:03 ntpd[15775]: parse: convert_rawdcf: start bit / parity check > FAILED for "###############RADMLS1248124P124812P1248121241248112481248P??" > 20 Mar 21:00:03 ntpd[15775]: parse: convert_rawdcf: start bit / parity check > FAILED for "###############RADMLS1248124P124812P1248121241248112481248P??" > 20 Mar 21:00:03 ntpd[15775]: parse: convert_rawdcf: start bit / parity check > FAILED for "###############RADMLS1248124P124812P1248121241248112481248P??" >
Despite LED shows plausible pulses there might be noise spikes triggering false pulses. I have had a DCF77 receiver where I had to filter out fake pulses. A scope will be able to show if signal quality is ok. Are you shure that you have polarity right? I think wrong polarity would make it trigger multiple times pr second. /hjj _______________________________________________ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
