loose-electron
Senior Fellow
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Best Design Tool = Capable Designers
Posts: 1638
San Diego California
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[quote author=rf-design link=1266871751/0#11 date=1268126222 What the point of tuned kicking XTAL? [/quote]
I am very aware of what people want to do with crystal kicking, and I have read some of the papers and patents on the subject. I have also designed enough RF front ends that wanted to be used in a time interleaved fashion and get things started up quickly is something I have had to deal with before.
However, I have also designed enough oscillators to know what works and what does not work.
More specific to crystal kicking, I have had my hands on a design in the lab and seen what happens, what the yield losses are.
They are unreliable, and have high yield losses because you cant "hit the kick frequency" with the needed accuracy.
If you can "crystal kick" with enough frequency accuracy to do something real towards speeding up the oscillation time, that means you already have an oscillator running with a well defined, highly accurate frequency.
If you got that, what need is there in starting up a second oscillator?
Even a tweaked and trimmed RC type oscillator will not be consistent enough to stimulate a crystal properly, thermal variance will make this drift out of band from the crystal. A tuned LC system will have a little better success but getting things aligned in frequency is a fussy prospect that is not viable in a volume product. Remember, the whole idea here is to create an accurate oscillation, and you don't have one readily available to work with.
I will come back to my original statement - If you want to get an oscillator up and running fast, look into running the device at lower amplitudes to avoid the slow ramp up in amplitude. There are also ways of running crystals at low amplitude, low power setups that can be kept running in the background and consume little power.
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