3 ms·

how more expensive is a "more expensive" oscillator?

by agos 2y ago

lxgr 2y ago
A few cents, as far as I understand, but that's not the only problem: You can get significantly more precision using an oven-controlled oscillator (frequency is temperature-dependent, and it's easier and more precise to control temperature to a known high setpoint than to compensate for the temperature-frequency curve using a thermometer), but these are, as the name implies, small ovens that consume additional electricity (on the order of 1-2 W, as far as I know). An additional base load of 1-2 W per oven and microwave would be pretty bad for the energy budget on a global scale, so just providing a time source from the power line they're already connected to is more efficient :) Other than oven-based oscillators, you can also use temperature-corrected oscillators; the Apple Watch does that, for example, and is supposedly about four times more accurate than a non-temperature-corrected MEMS, which in turn is already better than a quartz oscillator [1]. Not that it matters much, given that all models have at least a GPS receiver these days, as well as a battery life of about a day without charging, but I suppose it's a real benefit to all Apple Watch users working in faraday cage isolated bunkers without Wi-Fi :) [1] https://www.watchuseek.com/threads/apple-watch-oscillator-and-synchronization.2728930/ https://www.watchuseek.com/threads/apple-watch-oscillator-an...
- AdamH12113 2y ago
  > A few cents, as far as I understand, but that's not the only problem Nitpick: looking on Digi-Key, in quantity, a sub-ppm oscillator is ~5x more expensive than a 10 ppm crystal -- ~85 cents for the cheapest TCXO I can find vs. ~18 cents for a crystal. The frequencies are also much higher (tens of megahertz), which won't help with the power consumption. You're right about the power consumption, though.
generuso 2y ago
It depends. On the lower end of the spectrum, there are high volume products that offer somewhat better performance for just a tiny increase in cost, as mentioned in other comments. On the higher end of the spectrum there are laboratory-grade oscillators, for example the legendary Hewlett-Packard 10811 [1] and similar, which cost hundreds to thousands of dollars. These overlap in price with the lower end atomic clocks. [1] http://etoysbox.jp/Memo/3_Test_Equipments/HP_10811_OCXO/HP_10811_OCXO_Spec.html http://etoysbox.jp/Memo/3_Test_Equipments/HP_10811_OCXO/HP_1...

how more expensive is a "more expensive" oscillator?

by agos 2y ago

how more expensive is a "more expensive" oscillator?

lxgr 2y ago

A few cents, as far as I understand, but that's not the only problem: You can get significantly more precision using an oven-controlled oscillator (frequency is temperature-dependent, and it's easier and more precise to control temperature to a known high setpoint than to compensate for the temperature-frequency curve using a thermometer), but these are, as the name implies, small ovens that consume additional electricity (on the order of 1-2 W, as far as I know). An additional base load of 1-2 W per oven and microwave would be pretty bad for the energy budget on a global scale, so just providing a time source from the power line they're already connected to is more efficient :) Other than oven-based oscillators, you can also use temperature-corrected oscillators; the Apple Watch does that, for example, and is supposedly about four times more accurate than a non-temperature-corrected MEMS, which in turn is already better than a quartz oscillator [1]. Not that it matters much, given that all models have at least a GPS receiver these days, as well as a battery life of about a day without charging, but I suppose it's a real benefit to all Apple Watch users working in faraday cage isolated bunkers without Wi-Fi :) [1] https://www.watchuseek.com/threads/apple-watch-oscillator-and-synchronization.2728930/ https://www.watchuseek.com/threads/apple-watch-oscillator-an...

AdamH12113 2y ago
> A few cents, as far as I understand, but that's not the only problem Nitpick: looking on Digi-Key, in quantity, a sub-ppm oscillator is ~5x more expensive than a 10 ppm crystal -- ~85 cents for the cheapest TCXO I can find vs. ~18 cents for a crystal. The frequencies are also much higher (tens of megahertz), which won't help with the power consumption. You're right about the power consumption, though.

generuso 2y ago

It depends. On the lower end of the spectrum, there are high volume products that offer somewhat better performance for just a tiny increase in cost, as mentioned in other comments. On the higher end of the spectrum there are laboratory-grade oscillators, for example the legendary Hewlett-Packard 10811 [1] and similar, which cost hundreds to thousands of dollars. These overlap in price with the lower end atomic clocks. [1] http://etoysbox.jp/Memo/3_Test_Equipments/HP_10811_OCXO/HP_10811_OCXO_Spec.html http://etoysbox.jp/Memo/3_Test_Equipments/HP_10811_OCXO/HP_1...