RF Oscillator Mixing Circuit With Drift Correction
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Solution Overview
Problem
Oscillator circuits in RF transceivers face frequency drift issues due to harmonic or sub-harmonic frequencies generated during signal amplification, leading to power consumption and area increase with multiple phase locked loops, and interference in multi-frequency band applications where filtering out harmonics can result in loss of desired signals.
Innovation Solution
An oscillator circuit design incorporating a first oscillator in an open loop configuration and a second oscillator in a closed loop configuration, along with a mixer, filter, and correction circuit, which includes a phase error detector and integrator to attenuate unwanted frequency components and correct frequency drift by controlling the second oscillator's frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple phase locked loops are used to correct frequency drift, then frequency stability is improved, but power consumption and circuit area increase
Solution Approach 1:
The patent combines multiple oscillator circuits into a single integrated oscillator that generates multiple frequencies simultaneously. This merging approach eliminates the need for separate phase locked loops for each frequency, reducing both power consumption and circuit area while maintaining frequency stability through shared correction mechanisms
Solution Approach 2:
The patent implements a universal oscillator circuit capable of generating multiple frequencies (e.g., GPS and GLONASS bands) with a single device. This multi-functional oscillator replaces multiple specialized oscillators and their associated phase locked loops, achieving frequency stability across all bands without proportionally increasing power consumption or area
2Reliability
If harmonic frequency is filtered out using a band pass filter, then frequency drift is reduced, but desired signals in multi-frequency band applications are lost
Solution Approach 1:
The patent segments the frequency generation into multiple distinct oscillator circuits, each optimized for specific frequency bands. This segmentation allows each oscillator to operate independently with its own frequency correction, enabling selective filtering of harmonics for one band without affecting signal integrity in other bands
Solution Approach 2:
The patent applies local frequency correction to specific oscillator circuits based on their individual frequency bands. Each oscillator has tailored correction mechanisms that address its specific harmonic characteristics, allowing precise filtering of unwanted harmonics while preserving desired signals in different frequency bands with different quality requirements
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design effectively corrects frequency drift and minimizes power consumption and interference, enabling stable operation in multi-frequency band applications without losing desired signals, thereby improving the efficiency and accuracy of RF transceivers.
Implementation Method 1
a mixer coupled to the first oscillator and the second oscillator, and responsive to the signal having the first frequency and the signal having the second frequency to provide a signal having a third frequency
Implementation Method 2
a filter coupled to the mixer, and responsive to the signal from the mixer to attenuate the one or more frequency components and provide a signal having a desired frequency
Data Source
AI summary
Oscillator circuit for radio frequency transceivers. An oscillator circuit includes a first oscillator that generates a signal having a first frequency and a second oscillator that generates a signal having a second frequency. The oscillator circuit includes a mixer that is responsive to the signal having the first frequency and the signal having the second frequency to provide a signal having a third frequency and one or more frequency components. The oscillator circuit includes a filter that is responsive to the signal from the mixer to attenuate the one or more frequency components and provide a signal having a desired frequency. The oscillator circuit includes a correction circuit to correct a drift in at least one of the first frequency and the second frequency by controlling the second frequency, thereby correcting the drift in the third frequency and the desired frequency.