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| FIG. 1 is a block diagram of portions of flash analog-to-digital (A/D) converter 1 according to ... |
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| The circuit illustrated in FIG. 1 comprises an oscillator 10 which provides a periodic output ... |
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| Method of making master slice type integrated circuit device |
| It is hence a primary object of this invention to present master slice type integrated circuit ... |
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| Circuit and method for generating a clock signal |
| In accordance with the teachings of the present invention, a circuit and method for generating a ... |
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| Dynamic voltage reference which compensates for process variations |
| The present invention concerns a dynamic voltage reference circuit for generating one or more ... |
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| Amplifier arrangement and method and voltage controlled amplifier and method |
| It is, accordingly, an object of the present invention to provide an electronic amplifier ... |
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| Active noise and vibration control system |
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| Method and apparatus for microwave predistorter linearizer with electronic tuning |
| In one aspect of the invention, a predistorter linearizer for use with a radio frequency amplifier ... |
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| Spectral shaping of circuit errors in digital-to-analog converters |
| The present invention is a hardware-efficient DAC topology that can be used to achieve a variety of ... |
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Oscillator operable in a high impedance mode
| Details |
Inventors: Chan, Yiu K.; Tindorf, Krista;
Assignee: Motorola, Inc. (Schaumburg, IL)
Primary Examiner: Mis; David
Assistant Examiner:
Attorney, Agent or Firm: Bethards; Charles W., Buford; Kevin A.
An oscillator arranged to operate at an oscillation frequency includes a resonant structure 137, preferably a coaxial resonator, selected to resonate at a frequency, and an impedance 210, preferably a transistor 101 based common collector circuit, parallel coupled to said resonant structure 137, having a negative real part with a real magnitude and an imaginary part with an imaginary magnitude, said real magnitude being a function of said imaginary magnitude, said imaginary magnitude selected such that said real magnitude falls within 50% of a maximum at the oscillation frequency. |
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DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT Generally the instant disclosure concerns oscillators and more specifically a novel oscillator that offers improved performance at a reduced physical size.
As an overview the oscillator in an exemplary form may be viewed as a resonator based Colpitts oscillator where a transistor based active load on the resonator is operating in a voltage or high impedance mode rather than a current or low impedance mode.
One preferred embodiment is an oscillator including a resonant structure selected to resonate at a frequency, and an impedance parallel coupled to the resonant structure.
The impedance further has a negative real part with a real magnitude and an imaginary part with an imaginary magnitude where the real magnitude is a function of the imaginary magnitude and the imaginary magnitude has been selected such that the real magnitude falls within 50% of a maximum at the frequency.
The resonant structure is, preferably, a resonator such as a coaxial resonator.
A further preferred embodiment is an oscillator including a resonant structure having a characteristic impedance and an impedance that includes a transistor base terminal.
This impedance is AC connected to the resonant structure at the transistor base terminal and has an imaginary part with an imaginary magnitude that is selected to exceed the characteristic impedance at an operating frequency.
Still another preferred embodiment is a voltage tuned oscillator arranged to operate at an oscillation frequency including a resonator open at a first end, shorted at a second end, and having a characteristic impedance, a transistor having a base terminal, an emitter terminal, and a collector terminal, where the base terminal is ac connected to the first end of the resonator so as to load the resonator with an impedance having a first capacitive reactance, the emitter terminal is series coupled through a second capacitive reactance to the second end of the resonator, the second capacitive reactance is selected such that the first capacitive reactance exceeds the characteristic impedance, and the collector terminal is coupled to a load, and further a voltage variable reactance that is coupled to the resonator
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