Oscillators – Solid state active element oscillator – Transistors
Reexamination Certificate
1999-09-17
2002-10-08
Tse, Young T. (Department: 2634)
Oscillators
Solid state active element oscillator
Transistors
C331S046000, C331S059000, C331S135000, C375S332000, C329S304000
Reexamination Certificate
active
06462626
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
The present invention relates in general to receiving techniques and more particularly to a quadrature output oscillator device.
BACKGROUND OF THE INVENTION
Typically, quadrature outputs generated from voltage controlled oscillators are not ideal, i.e. the phase difference between the in-phase and quadrature-phase signal components are 90°±some error. The error in this phase difference is mostly due to device mismatch. However, many receiver topologies rely on precise quadrature in order to achieve frequency image rejection in the received signal. The quality of reception is degraded, in the presence of frequency images in the received signal, due to the imprecise quadrature component signal generation in the receiver. Frequency image rejection could be performed by passive filters, but these passive filters result in increased design complexities and higher costs. Therefore, it is desirable to have precise quadrature to achieve the desired receiver circuit performance.
SUMMARY OF THE INVENTION
From the foregoing, it may be appreciated that a need has arisen for a receiver that implements ideal in-phase and quadrature-phase signal components in order to effectively achieve proper frequency image rejection. In accordance with the present invention, a quadrature output oscillator device is provided that substantially eliminates or reduces disadvantages and problems associated with conventional quadrature output voltage controlled oscillator devices.
According to an embodiment of the present invention there is provided a quadrature output oscillator device that includes a first voltage controlled oscillator that generates a first output and a second output, wherein the second output of the first voltage controlled oscillator is an in-phase signal component. A second voltage controlled oscillator also generates a first output and a second output, wherein the second output of the second voltage controlled oscillator is a quadrature-phase signal component. A first amplifier receives the first and second outputs from the second voltage controlled oscillator. The first amplifier generates a first feedback signal coupled to the first output of the first voltage controlled oscillator and a second feedback signal coupled to the second output of the first voltage controlled oscillator. A second amplifier receives the first and second outputs from the first voltage controlled oscillator. The second amplifier generates a first feedback signal coupled to the first output of the second voltage controlled oscillator and a second feedback signal coupled to the second output of the second voltage controlled oscillator. A gain adjustment unit controls a gain of the first amplifier and the second amplifier in order to provide ideal in-phase and quadrature-phase signal components at the second output of the first voltage controlled oscillator and the second output of the second voltage controlled oscillator, respectively.
The present invention provides various technical advantages over conventional quadrature output voltage controlled oscillator devices. For example, one technical advantage is to provide ideal quadrature outputs from voltage controlled oscillators. Another technical advantage is to eliminate the use of passive filters in receiver topologies. Yet another technical advantage is in compensating for device mismatches within voltage controlled oscillators. Other technical advantages may be readily ascertainable by those skilled in the art from the following figures, description, and claims.
REFERENCES:
patent: 5489878 (1996-02-01), Gilbert
patent: 5561398 (1996-10-01), Rasmussen
patent: 5917383 (1999-06-01), Tso et al.
patent: 6025765 (2000-02-01), Brown
patent: 6313688 (2001-11-01), Lee et al.
patent: 6356747 (2002-03-01), Miquel et al.
patent: 6377315 (2002-05-01), Carr et al.
patent: 0 523 854 (1993-01-01), None
“SP24.6: A 900 MHz CMOS LC-Oscillator with Quadrature Outputs”, Rofougaran, et al., 1996 IEEE International Solid-State Circuits Conference, Feb. 10, 1996, pp. 392-393.
Neerings Ronald O.
Texax Instruments Incorporated
Tse Young T.
LandOfFree
Quadrature output oscillator device does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Quadrature output oscillator device, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Quadrature output oscillator device will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2943003