Wideband oscillator with bias compensation
AssigneeHewlett-Packard Company
InventorBarton L. McJunkin
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Abstract
An RF oscillator is disclosed that can be tuned to operate over a wide range of frequencies while maintaining advantageous bias conditions. The oscillator includes circuitry that adjusts an oscillator bias signal in response to changes in oscillator frequency and/or ambient temperature, and does so without resort to using the same signal for both bias and frequency control. By so doing to control parameters such as phase noise, output power and compression angle, both the frequency range and temperature range of an oscillator can be extended, while simultaneously improving the oscillator's performance.
Claims14
A method of operating an electronically tunable wideband oscillator that includes an active device, the oscillator being operable to produce an oscillator signal having a frequency above 30 MHz, the method comprising:
- applying a bias signal to the active device;
- receiving a parameter signal receiving to a parameter of oscillator operation;
- and
- varying the bias signal applied to the active device in response to the parameter signal;
- wherein the bias signal is automatically adjusted in response to the parameter to improve an oscillator signal characteristic other than oscillator frequency.
An oscillator comprising:
- an active device;
- a bias circuit coupled to the active device for applying a bias signal thereto;
- a resonant circuit coupled to the active device and cooperating therewith to provide a resonance at an oscillation frequency, said resonant circuit including a frequency control element that is responsive to a frequency control signal for varying the resonant frequency of said oscillator;
- an input for receiving a frequency control signal corresponding to a desired oscillation frequency and for applying said frequency control signal to the frequency control element;
- and
- a compensation circuit coupled to the bias circuit and including means for varying the bias signal applied to the active device in response to variations in the frequency control signal;
- wherein the bias signal and the frequency control signal are distinct signals.
An oscillator comprising:
- an active device;
- a bias circuit coupled to the active device for applying a bias signal thereto;
- a temperature sensor for providing an electrical signal related to an ambient temperature;
- and
- a compensation circuit coupled to both the temperature sensor and the bias circuit and including means for adjusting the bias signal applied to the active device in response to variations in the ambient temperature to improve an oscillator signal characteristic other than frequency but without correcting a temperature induced shift of frequency.
Dependencies are inferred from the claim text.