2018年11月16日 (五) 20:05的版本

1 Station

1.1 China

Freq: 68.5KHz

Code: BPC

Ops: NTSC

https://en.wikipedia.org/wiki/BPC_(time_signal)

1.2 Japan

Freq: 40KHz/60KHz

Code: JJY

Ops: NICT

• http://jjy.nict.go.jp/
• https://en.wikipedia.org/wiki/JJY

1.3 USA

Freq: 60KHz

Code: WWVB

Ops: NIST

• https://en.wikipedia.org/wiki/WWVB
• https://www.nist.gov/pml/time-and-frequency-division/radio-stations/wwvb

1.4 England

Freq: 60KHz

Code: MSF

Ops: NPL

• https://en.wikipedia.org/wiki/Time_from_NPL
• http://www.npl.co.uk/science-technology/time-frequency/products-and-services/time/msf-radio-time-signal

1.5 German

Freq: 77.5KHz

Code: DCF77

Ops: PTB

• https://www.ptb.de/cms/en/ptb/fachabteilungen/abt4/fb-44/ag-442/dissemination-of-legal-time/dcf77.html
• https://en.wikipedia.org/wiki/DCF77
• https://www.eecis.udel.edu/~mills/ntp/dcf77.html

1.6 Swiss

Freq: 75KHz

Code: HBG

Ops: METAS

• https://en.wikipedia.org/wiki/HBG_(time_signal)

2 Format

2.1 BPC

载波 68.5KHz，脉宽调制 (Pulse-Width Modulation，PWM)，码率 1 Hz

每个编码脉冲宽度为 0.1s，0.2s，0.3s 或 0.4s，分别代表四进制的 0，1，2，3。一串四进制的数字是由播发时刻的秒、时、分、星期、日、月、年插入几个校验位组成，长度为 20s

2.2 JJY

载波 40KHz 和 60KHz，脉宽调制 (Pulse-Width Modulation，PWM)，格式类似美国 WWVB 码：

2.3 WWVB

载波 60KHz，脉宽调制 (Pulse-Width Modulation，PWM) 和 相位调制 (Phase Modulation, PM)

2.4 DCF77

载波 77.5KHz，AM 和 PM

https://en.wikipedia.org/wiki/DCF77

3 解调芯片

3.1 CME8000

• http://www.c-max.com.hk/assets/technology/rct/rct_ic/cme8000/CME8000-B17.pdf

3.2 CME6005

• http://aitendo3.sakura.ne.jp/aitendo_data/product_img/test/D606C/CME6005-A8-1.pdf

3.3 DL6005

• http://www.jfd-ic.com/Documents/DL6005.pdf