how to generate a precisely clock frequency oscillator?

[liletian]

generate clock with oscillator

Hi Guys
How to generate a precisely oscillator@2.2GHZ with precision of 0.1%? Do I have to use LC oscillator or I can still get it in inverter oscillator?
Thanks

 

[ieropsaltic]

I think that a stand-alone osciilator can not achieve the required stability at the given frequency. You can use a crystal oscillator at lower frequency which can provide very good stability then use a PLL locked to this crystal oscillator to perform frequency multiplication.
Another method is to use an over-tone crystal oscillator, butI'm not sure if an over-tone crystal oscillator can achieve the 2.2GHz.

 

[FvM]

I think a high Q oscillator can achieve the required stability, e. g. with a cavity resonator. It also needs sufficient decoupling from load and supply variations and possibly temperature compensation or thermostatisation.

 

[webdog]

1 to 10-3 is not that difficult i.e. you are asking for a stability of 2-3 MHz at 2,5 GHz. Not that easy with a L/C oscillator, but a Hi-Q resionator should do it. Cavity might be one option, or a DRO (dielectric resonator), Make your own resonator with a low-loss coax (semi rigid) and a good multi turn capacitor (johanssen), and be very careful with temperature drift, you will be there.

Another way would be to start with a crystal oscillator and mulitply to what ever frequency you want. Draw back is spurious level and the amplifiers and filters needed.

Using a PLL would be quite simple and you can optimize the oscillator and loop filter for just one frequency.

 

[jonnasi]

I would suggest making it with a Temperature Compensated Crystal Osillator (TCXO), PLL IC from f.x. Analog Devices and a VCO that fits your frequency range. By that make a PLL Frequency Synthesizer which should be rather stable.
Also this requires a Loop Filter (LPF).

Hope that helps

 

[jecyhale]

Hi Guys
How to generate a precisely oscillator(at)2.2GHZ with precision of 0.1%? Do I have to use LC oscillator or I can still get it in inverter oscillator?
Thanks

PLL Frequency Synthesizer can do that. But you need a low freqnecy TCXO as reference.

 

[kspalla]

Hi,
The stability of the PLL is defined by the ref oscillator, preferably TCXO.
Si you can have low frequency highly stable and multiply with suitable number to have the desired frequency.

 

[webdog]

Reading the OP, there is NO need for TCXO or any other special reference if he chooses to use a PLL. If he needs 0.1% stability, this will refelct the stability of the reference, i.e. same stability needed there! Pick a 10 MHz crystal, or a redy made cheap XO it will certainly be way better than 10-3 in stability. Use a simple PLL and be done!