[time-nuts] eWWVB 1235UA UltrAtomic clock / ES100

[Tom Van Baak]

I updated the http://leapsecond.com/pages/ultratomic/ teardown page with a performance plot made from data last year.

The plot is at http://leapsecond.com/pages/ultratomic/ultratomic-10d-2.png

The La Crosse 1235UA UltrAtomic radio controlled wall clock, which came out a few years ago, uses the ES100 WWVB BPSK chip. It may still be the only commercial clock that receives the new enhanced WWVB format.

The 1235UA contains two chips: one is the 16 MHz ES100 radio receiver and the other is a 32 kHz MCU that drives the hands of the clock and occasionally talks to the ES100.

Given the "new WWVB BPSK dev board" thread some weeks ago, I hope a number of you will post results of your newly acquired ES100 eWWVB receiver dev boards. I expect the ES100 results will be significantly better than the 1235UA wall-clock. The latter is limited by infrequent updates, timebase drift, ~30 ms quantization in its phase corrections, and a bias of about -0.1 second. To me this sounds like a limitation in the 1235UA f/w, not a limitation in the ES100 chip itself.

/tvb
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