Patent ID: 7459946
Filing Date: 2008-12-02
Classification: H03H,H03J,H03L

Abstract:
1. A circuit for generating a reference signal, comprising: an oscillation generator that generates an oscillator signal at an output thereof, having an oscillator signal frequency; a phase-regulated quartz filter having a signal input connected to the output of the oscillator generator to receive the oscillator signal therefrom, a control input, and an output, said quartz filter being configured to form a low-noise reference signal having long term stability from said oscillator signal, said quartz filter emitting said low-noise reference signal at the output thereof; a frequency multiplier having an input connected to the output of the quartz filter to receive the low-noise reference signal therefrom, said frequency multiplier being configured to form a high-frequency reference signal from said low-noise reference signal; and a phase control circuit connected across said signal input and said output of said phase-regulated quartz filter to receive said output of said quartz filter and said output of said oscillator generator as inputs thereto, said control circuit being configured to generate a control signal supplied to said control input of said phase-regulated quartz filter to adjust a center frequency of said phase-regulated quartz filter to cause said quartz filter to exhibit a constant transmission phase and to cause said center frequency of said quartz filter to coincide with said oscillator signal frequency.