You could use a PLL chip with a crystal ... for a digital clock signal ...
or do you mean a clock that measures time? Then you could use an RTC chip and a microcontroller with your choice of display technology. If you trust NTP, you could even forego the RTC and use a wireless microcontroller to synchronise its free running clock regularly.
Perhaps think about putting more detail into your question so that you can solicit useful replies.
You could use a PLL chip with a crystal ... for a digital clock signal ...
or do you mean a clock that measures time? Then you could use an RTC chip and a microcontroller with your choice of display technology. If you trust NTP, you could even forego the RTC and use a wireless microcontroller to synchronise its free running clock regularly.
Perhaps think about putting more detail into your question so that you can solicit useful replies.
