Patent ID: 6278338
Filing Date: 2001-08-21
Classification: H03B,H03L

Abstract:
A crystal oscillator generating an amplitude controlled crystal oscillator output signal comprising:a) a crystal resonator circuit having a crystal resonator that generates an oscillation signal having a pre-determined oscillation frequency;b) an inverting amplifier having a first amplifier input, a second amplifier input and an inverting amplifier output, wherein the first amplifier input is coupled to the crystal resonator and receives the oscillation signal, and wherein the inverting amplifier outputs an inverted amplified output signal that is an inverted amplified version of the oscillation signal;c) a bias circuit having a bias circuit input and a bias circuit output, wherein the bias circuit output generates a bias circuit output signal that is controlled by the bias circuit input, and wherein the bias circuit output signal is coupled to the second amplifier input;d) a reference circuit generating a reference output signal, wherein the reference output signal is variable and can be set to a predetermined selected reference signal value; ande) a peak detector having a first peak detector input, a second peak detector input and a peak detector output generating a peak detector output signal, wherein the first peak detector input is coupled to receive the inverted amplified output signal, and wherein the second peak detector input is coupled to receive the reference output signal, and wherein the peak detector output is coupled to the bias circuit input, and wherein the peak detector compares the inverted amplified output signal to the reference output signal and adjusts the peak detector output signal until a desired peak amplitude of the inverted amplified output signal is achieved.