FMCW Frequency Multiplier Using Square-Wave Third Harmonic Extraction
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Solution Overview
Problem
Existing frequency multiplier designs for generating frequency-tripled signals in radar systems face challenges such as complex design, risks associated with Process, Voltage, and Temperature (PVT) variations, and inefficient power consumption due to low power injection locking requirements.
Innovation Solution
A frequency multiplier circuit that includes a signal generator to produce a square wave signal from a Frequency-Modulated Continuous Wave (FMCW) signal, and a third harmonic amplifier to amplify the third harmonic component of the square wave signal, thereby generating a frequency-tripled FMCW signal with improved efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If an oscillator is used to generate oscillation near the tripled frequency and a third harmonic signal is generated by using a nonlinear characteristic of an amplifier for injection-locking, then a frequency-tripled signal with higher power can be output, but the design becomes more complicated and introduces risks such as failure to start oscillating or frequency offset under PVT variations
Solution Approach 1:
The patent extracts and utilizes the third harmonic component directly from the square wave signal generated by the signal generator, rather than generating it through a complex oscillator and amplifier system. This extraction approach simplifies the overall design while maintaining the desired frequency tripling function and output power.
Solution Approach 2:
The patent segments the frequency multiplication function into distinct components: the signal generator produces a square wave containing rich harmonic components, and the third harmonic amplifier selectively amplifies the third harmonic component. This segmentation allows each component to be optimized independently, reducing overall system complexity.
2Adaptability or versatility
If a large injection Locking Range is obtained by increasing the power of the frequency-tripled signal to be injected, then the locking range increases, but the nonlinear amplifier consumes more power
Solution Approach 1:
The patent changes the approach from adjusting injection signal power to achieve locking range to using a dedicated third harmonic amplifier that is specifically designed to amplify the third harmonic component. This parameter change allows for efficient power amplification targeted at the specific frequency component needed, improving both locking range and power efficiency.
3Productivity
If the third harmonic component is generated by an oscillator in the related art, then frequency tripling can be achieved, but the third harmonic component has a lower proportion, resulting in lower generation efficiency
Solution Approach 1:
The patent converts the inherent characteristic of square wave signals (which naturally contain rich odd harmonic components) into a benefit by directly utilizing the third harmonic component present in the square wave. This approach transforms what could be considered an unwanted harmonic distortion in traditional sinusoidal generation into a useful resource for efficient frequency tripling.
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
The proposed solution enhances the generation efficiency of frequency-tripled FMCW signals by extracting a higher proportion of third harmonic components, reducing phase noise, and improving stability across varying PVT conditions.
Implementation Method 1
a third harmonic amplifier, coupled to the signal generator and is configured to amplify a third harmonic wave in the square wave signal and output a frequency-tripled FMCW signal
Data Source
AI summary
Disclosed are a frequency multiplier, a signal transmitter and a radar chip. The frequency multiplier includes a signal generator that is configured to receive an FMCW signal and output a square wave signal at a frequency same as a frequency of the FMCW signal; and a third harmonic amplifier that is coupled to the signal generator and is configured to amplify a third harmonic wave in the square wave signal and output a frequency-tripled FMCW signal. The above-mentioned solution can improve the generation efficiency of the frequency-tripled signal.