From Colpitts oscillator to Pierce with frequency multiplication

[t2theommy]

Hi there,

this is my first post in here an I hope you can help me. I`m tyring to design a Pierce oscillator @ 450MHz.
My task is, to use a quartz with a basic frequency with, I don`t know... 10-20MHz or a bit more and get to
450MHz with frequency multiplication. I just designed a very simple Colpitts and got it working @ roughly 5MHz.



Now my question is, how do I get to a Pierce oscillator, and how do I do it with ADS?
I don`t know which quartz I should choose, and with the ones I took I always got fail messages...

Would be great if you could help me

bye, t2theommy

 

[etmabreu]

450 MHz would be the 45th overtone of 10MHz. Not a good idea...

 

[t2theommy]

450 MHz would be the 45th overtone of 10MHz. Not a good idea...

Okay, that`s right... so, what frequency would you recommend? something like 50MHz? Would be the 9th...
But the real problem is that I don`t really know how to design it with such a quartz in ADS. I`ve never done something like that
circuit with the programm.

 

[etmabreu]

Okay, that`s right... so, what frequency would you recommend? something like 50MHz? Would be the 9th...
But the real problem is that I don`t really know how to design it with such a quartz in ADS. I`ve never done something like that
circuit with the programm.

Yes, usually the maximum fundamental frequency you can find in a crystal is around 50MHz.
Never saw anything done around the 9th harmonic (3rd or 5th is common).
For 450 MHz I would probably look for a PLL based synthesizer.

Are you designing the pierce oscillator just as an exercise or do you need it for a real application?

 

[t2theommy]

Okay, that sounds quite logic...

It`s a part of my Bachelor`s thesis, and my task is to design it with ADS.
And I shall do it with a Pierce oscillator and a quartz in overtone mode.

Mhh, so it`s going to be a little complicated I guess...

But nevertheless, could you explain how to integrate a quartz into my colpitts with ADS?
And how should my LC - resonant circuit look like to "select" the 3th, 5th and so on overtone?

Thanks for your help.

 

[etmabreu]

A few ideas:

https://www.icmfg.com/crystaloscillatordata.html


I'm not used to design oscillators, although I know a few things about them.
In the previous link you have a few hints about a colpitts and pierce oscillators including crystals and overtone design.
Doing that in ADS should be quite similar as in any other simulator.

 

[t2theommy]

Thanks a lot, this page looks very helpful. I`ll read it this weekend and hope I can go on with my work...
Have a nice weekend and thanks again