Hi
> On Feb 17, 2018, at 11:01 PM, Nick Sayer via time-nuts <time-nuts@febo.com> > wrote: > > It’s been a while since I’ve posted here, but I’ve had a bunch of irons in > the fire. I’m working on adapting my GPSDO to the ECS ECOC-2522, which the > manufacturer claims has a short term ADEV in the low -12s, but I haven’t > gotten it doing that well yet. At least on this data sheet: https://www.ecsxtal.com/store/pdf/ECOC-2522.pdf <https://www.ecsxtal.com/store/pdf/ECOC-2522.pdf> They don’t say much of anything at all about ADEV. OCXO’s in the little packages are rarely super stars when it comes to ADEV. Bob > > But one thing that is ready (well, electronically it is - I’m still working > on the laser cut case for it) is my GPS Talking Clock. > > The story is that I called the USNO time number at midnight on New Year’s > Day, but the wife noted that it was the wrong time zone. That got me > thinking, and I wound up designing a GPS driven simulacrum. > > It’s an ATXmega32E5 with the usual Venus838 timing module and a µSD card > slot. The card is loaded with audio samples that the 32E5 plays back through > its DAC. I got double-buffered DMA to work to feed the DAC, so audio playback > is a largely background task. I just have to fill the buffer with the next > block from the file every ~30 ms or so. The ticks and beeps are generated > from an on board 1 kHz source and are turned on by a PPS ISR, so they’re as > accurate as possible. The whole thing is basically as accurate as an aural > clock can be - the latency induced by the speed of sound has far more impact > than anything else. > > While the audio is turned off, the clock can also do Westminster Quarters (or > any other chime you wish to load in). > > The µSD card is FAT formatted and the audio sample files are easy to make > with ‘sox’ (raw, 1 channel, 8 kHz, 16 bit little-endian, unsigned), so > there’s no reason you can’t substitute my voice with your own, or make your > own chimes. > > It’s available at https://www.tindie.com/products/nsayer/gps-talking-clock/ > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
