[time-nuts] wtd: WWVB info

Tom Van Baak tvb at LeapSecond.com
Sun Aug 9 16:20:55 EDT 2015

> This data sheet is one of a few receivers from a few vendors:
> http://www.datasheetcatalog.com/datasheets_pdf/U/4/2/2/U4221B.shtml
> Looking at the data sheet link shows the internals of the receiver chip.
> This chip outputs the serial stream of the WWVB pwm data.
> From there any MCU can decode that stream via bit-bang.

Hi Don,

About the U4221B -- that TEMIC series was widely used in WWVB receivers 15 to 20 years ago. The problem for many hobbyists today is that these very nice chips have long since been out of production. Note the May '96 date on the datasheet. 

I figure there minimal low-volume demand -- just not enough WWVB hobbyists in the world. And for high-volume -- companies like Sony, Seiko, Casio, and Junghans typically roll their own chips, one where they can fully integrate the receiver into the single IC that does everything else: clock, calendar, display, subcode decode, motor control, power management (solar charge).

WWVB RCC (radio controlled clocks) and watches have evolved -- many companies now offer "multi-band" clocks that automatically handle all the world-wide LF broadcasts (WWVB,JJY40/60,MSF,DCF77). This further lowers the market demand for a WWVB-only plain receiver IC.

Under my http://leapsecond.com/pages/sony-wwvb/ page is a full set of vintage Temic datasheets:


And lastly, this old Temic time code document is a must-read for anyone playing with RC clocks:



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