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TCXO vs PLL or DDS. Frequency stability comparison?

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neazoi

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Hello,
Which is generally speaking more frequency stable?

1. A TCXO
2. A PLL
3. A DDS
 

Kripton2035

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tcxo... only tcxo is a clock source
pll and dds rely on a clock source that determine their stability ...
 

biff44

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Since all 3 can use a TCXO as a frequency reference, they have exactly equal frequency stability specs.
 

neazoi

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Since all 3 can use a TCXO as a frequency reference, they have exactly equal frequency stability specs.
But the clock is always a TCXO or other reference like rubidium or GPS, so all these are dependent on this stable clock. If clock is not stable, the output of the dds of pll will not be stable as well if I have understood well.

In a world composed of so many semiconductor stuff, it is still admirable that a crystal like the quartz still can give unbeatable stability.
Not to mention about the phase noise that can be achieved in a well designed Xtal osc.
Thank you all for the replies
 

ahgu

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if TCXO is the clock source, after it goes through the PLL, will it still have same stability?
For example, TCXO oscillator is 1ppm & 16MHz, after the PLL, the freq becomes 48Mhz, will the 48MHZ clock still maintain 1ppm stability?
 

biff44

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Neazoi, you are always asking about 1960's technology. Are you asking about modern PLLs and DDSs? Or some cat's whisker BFO oscillator superregenerative thing?
 

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