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| Clock circuit design idea |
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| tooki:
Not the best quality video, but the newest, showing that behavior next to the newest-generation departure signs (big TFTs) (where they easily could have integrated the clock into the flat panel) https://youtu.be/SKPgZj1vb8o |
| Gyro:
--- Quote from: Connecteur on July 25, 2020, 06:34:44 pm --- --- Quote from: m98 on July 25, 2020, 05:33:02 pm ---That's just not how this works. Clocks don't only drift from a constant frequency offset. --- End quote --- Seems to me whatever the cause, it could be mitigated by this simple time-correcting solution. --- End quote --- I have an alarm clock program on my Palm TX PDA (yes I know, ancient) that does exactly this. It applies a time correction in terms of fractional seconds per day to the crystal derived clock. The drift compensation actually works very well. |
| David Hess:
There is no reason that a quartz clock cannot learn to correct its drift and temperature compensation, but typically it is not done because they are close enough. If you did want a better one, then a much more accurate TCXO could be used which some high end clocks do. |
| Connecteur:
I'm sure "close enough" is the reason we don't see it incorporated into most clock circuits today, but why couldn't it just be part of normal electronic clock design? |
| David Hess:
--- Quote from: Connecteur on July 26, 2020, 03:09:20 am ---I'm sure "close enough" is the reason we don't see it incorporated into most clock circuits today, but why couldn't it just be part of normal electronic clock design? --- End quote --- The first thing which occurs to me is that it requires state to be saved unless it is acceptable that the calibration be lost if power is removed. Saving state will mean some floating gate memory and nobody is going to build a cheap clock IC on a process which provides that, or add a second IC. |
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