Oscillators – Electromechanical resonator – Crystal
Reexamination Certificate
2006-10-17
2006-10-17
Pascal, Robert (Department: 2817)
Oscillators
Electromechanical resonator
Crystal
C331S074000, C331S1160FE, C331S183000, C331S186000
Reexamination Certificate
active
07123113
ABSTRACT:
An oscillator circuit is provided that is preferably a crystal oscillator, where voltage placed across the crystal is regulated. The regulated voltage or amplitude of the cyclical signal across the crystal is monitored and maintained through a regulation circuit that measures a peak voltage across the crystal. Once the peak voltage exceeds a predetermined setpoint value, then a controller within the regulation circuit will reduce a biasing current through an amplifying transistor within the amplifier coupled across the crystal input and output nodes. By regulating the biasing current, gain from the amplifier is also regulated so that unwanted non-linearities and harmonic distortion is not induced within the crystal to cause frequency distortion and unwanted modes of oscillation within the crystal. The amplifier is preferably symmetrical in that the amplifier sources and sinks equal current to reduce unwanted peaks at the negative or positive half cycles of the sinusoidal signal.
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Brennan Aaron
McMenamy Mike
Stiff Jonathon
Cypress Semiconductor Corp.
Daffer Kevin L.
Daffer McDaniel LLP
Goodley James
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