The following are a list of whitepapers and articles prepared by Rakon in answer to various questions from customers. They are presented here for your reference, should you have any specific questions please contact us at any time.
SINGLE TRANSISTOR CRYSTAL OSCILLATOR CIRCUITS
The majority of modern crystal oscillator circuits fall into one of two design categories, the Colpitts / Clapp oscillator and the Pierce oscillator. There are other types of single transistor oscillators ( Hartley and Butler for example ), but their usefulness and application is beyond the scope of this discussion.
IC CRYSTAL OSCILLATOR CIRCUITS
The majority of IC’s with built in crystal oscillator circuits use the Gated Pierce design where the oscillatois built around a single CMOS inverting gate.
TIME KEEPING WITH QUARTZ CRYSTALS
“The only reason for time is so that everything doesn't happen at once” said Albert Einstein. One can only assume he wasn’t talking about synchronised global networks when he made this statement.
PHASE NOISE / JITTER IN CRYSTAL OSCILLATORS
Before we can cover the sources of Phase Noise / Jitter in Crystal Oscillators we need to de-mystify some of the wording associated with the measurement, so lets start with a simple description of Phase Noise and Jitter.
RELATIONSHIP BETWEEN PHASE NOISE AND JITTER
When specifying noise performance the test has to impose some ‘boundaries’ to the measurement. For Phase Noise this is the simple form of a ‘from – to’ figure (like Phase noise from 10Hz to 1MHz). For Jitter measurement it is a little more complex. To specify Jitter a sampling period needs to be specified and also a bandwidth.
RELATIONSHIP BETWEEN PHASE NOISE AND BIT ERROR RATIO
As stated in the article ‘RELATIONSHIP BETWEEN PHASE NOISE AND JITTER’ the Phase Noise of a stable Crystal Oscillator can be converted to an Rms Jitter figure. This Rms Jitter figure can be analysed further to show the contribution the Crystal Oscillator makes to the overall system Bit Error Ratio.
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