宅男乙 wrote:
微處理基本上也都是...(恕刪)
另外, 好一點的設計是用 MEMS 不是 震盪晶體, 而且每天在半秒之內..(有些廠商, 還有更厲害的)
去看看稍微進階資料...有時會擴展視野..不會停在初階電子知識,
https://www.maximintegrated.com/en/app-notes/index.mvp/id/5589
當然, 回到原來討論的, 用TCXO, 也更可做到 +-3.5ppm (+-0.3sec/day)
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Considered the industry’s most accurate RTC at the time, the DS3231S incorporated a 32kHz tuning fork crystal into a highly reliable 16-pin, 300-mil SO package. This highly integrated RTC provided a frequency accuracy of less than ±3.5ppm over the -40°C to +85°C temperature range, accuracy that is equivalent to less than ±0.3ss/day. It set a new standard for clock accuracy.
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一般我們看到 RTC IC 實在便宜的可以, 但做到好一點的 TCXO 要到美金 $3-5, 整個模組也不少錢...
好一點的 "車用時鐘模組" 是用這種設計..(不一定豪華車就是用這種好模組就是, 要看看設計師,有沒注意到)
