Images of DCF77

DCF77 Receiver Modules

子どもを虐待から守る科学アセスメントとケアのエビデンス【電子書籍】[ 原田隆之 ]

Arduino controlled DCF77 Synchronized Astronomical Regulator Master Clock Arduino Projects Diy, Arduino Board, Diy Tech, Circuit Diagram, Hacking Computer, Microcontrollers, Diy Electronics, Unix, Ham Radio

“Connect” to an atomic clock in space! GPS, DCF77

THD Arduino Projekte

Dreams 39巻【電子書籍】[ 七三太朗 ]

DCF77 Empfänger Funkuhr Receiver 77.5kHz for Europe

DCF77 - Radio Date and Time Receiver

DCF77-Receiver Kit with Signal level meter

カラスヤサトシ（4）【電子書籍】[ カラスヤサトシ ]

WARNING - TRANSMITTING YOUR OWN TIME-SIGNAL IS EVIL. Well, our meetings take place on wednesdays at 10:30 (sharp). A radio controlled clock is used to determine whether you are late (and must bring a cake next time) or not. Unfortunately the identical radio controlled clock in my office always shows a different time :-( After baking a lot of cakes, I thought about synchronising these disreputable clocks ... The straight approach would be to have a crystal oscillator, amplitude modulated by a microprocessor. As we did promise (2859!) not to abuse the donated crystals for that reason, another approach is used here - which makes the system even more flexible. To generate a stable frequency, usually a PLL is used (or DDS). In order to gather some insight in the nature of a PLL, a small PLL-Demoboard (including a small PLL-Seminar) was designed. CallsignFrequencyModulationLocation MSF60 kHz-Anthorn (United Kingdom) HBG75 kHzASKPrangins (Switzerland) DCF7777.5 kHzASKFrankfurt (Germany) TDF162 kHz-Allouis (France) HBCZ7777.5 kHzASKunknown :-) Table above : some frequencies, generated easily with jumpers on the PLL-Demoboard ... The project uses three PCB's, one for generating the carrier (PLL-Demoboard) and one for the correct (!) modulation of the carrier and one for the Power Supply. As radio controlled clocks use some kind of checking the received codeword( 30th of February will never be accepted :-) there must be a microprocessor, assuring that the sent generated codeword is valid. • PCB#1 may be any clock source of the carrier of your choice. We use the PLL-Demoboard. • PCB#2 is the Frontpanel, containing the Microprocessor and ASK Modulator. (Picture below) • PCB#3 is some kind of Power Supply, delivering +12V...+30V/200 mA and + 5V/100 mA. Picture above : The Mainboard, assembled, behind the Frontpanel. CallsignFrequencyModulationLocationMSF60 kHz-Anthorn (United Kingdom)HBG75 kHzASKPrangins (Switzerland)DCF7777.5 kHzASKFrankfurt (Germany)TDF162 kHz-Allouis (France)HBCZ7777.5 kHzASKunknown :-) The Amplitude Modulation is done with 4 AND-Gates and a R-2R Network. It is therefore possible to modulate the TTL Signal with 16 Steps. This is somehow cracking a nut with a sledgehammer, but we wanted to present something nifty to comply with the 'educational aspect'. Note: As we wanted to have a single sided PCB, we reduced this later to 3 Bit. Where a '0' is represented by a 100 ms drop to 25% Amplitude and a '1' drop lasts 200 ms. Picture above : Horizontal: 200 ms/DIV, Vertical: 1 V/DIV Bit/Sec.MeaningRemarks0Start of a Minutealways = 01-14reserved / for future use 150=Normal Antenna, 1=Backup Antenna 16Summer Time AnnouncementSet 1 hour before17Summer Time 0=No, 1=Yes 18Winter Time 0=No, 1=Yes 19Leap Second announcementSet 1 hour before20Startbit encoded Timealways = 121Minutes, weight = 1 22Minutes, weight = 2 23Minutes, weight = 4 24Minutes, weight = 8 25Minutes, weight = 10 26Minutes, weight = 20 27Minutes, weight = 40 28Parity Bit Minutes (even)Bits 21 - 2829Hours, weight = 1 30Hours, weight = 2 31Hours, weight = 4 32Hours, weight = 8 33Hours, weight = 10 34Hours, weight = 20 35Parity Bit Hours (even)Bits 29 - 3436Day of the Month, weight = 1 37Day of the Month, weight = 2 38Day of the Month, weight = 4 39Day of the Month, weight = 8 40Day of the Month, weight = 10 41Day of the Month, weight = 20 42Day of the Week, weight = 1Monday = 143Day of the Week, weight = 2Tuesday = 244Day of the Week, weight = 4Wednesday = 345Number of the Month, weight = 1 46Number of the Month, weight = 2 47Number of the Month, weight = 4 48Number of the Month, weight = 8 49Number of the Month, weight = 10 50Year, weight = 1( 00 - 99 )51Year, weight = 2 52Year, weight = 4 53Year, weight = 8 54Year, weight = 10 55Year, weight = 20 56Year, weight = 40 57Year, weight = 80 58Parity Bit Date (even)Bits 36 - 5759Minute SyncCarrier unmodulatedA radio controlled clock is modified therefore, that the generated Signal is fed directly into the Amplifier following the Antenna. (Decoupling with an 1 kΩ Resistor). It is assumed, that the portion radiated through the Antenna is very small, as we use an Attenuator of 30 dB. (and of course operate it in a fully shielded room :-) Connecting the Signal Generator to the Clock - using a DC-Block and a 30 dB Attenuator from Mini Circuits - the Situation is as follows :