High-Order Harmonic RF Mixing for Lower-Power LO Design
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Solution Overview
Problem
Current signal mixing technologies face challenges in reducing the wide tuning range of local oscillator (LO) frequencies without increasing power consumption, particularly in communication systems where high frequencies require complex and power-intensive designs.
Innovation Solution
The method employs high-order harmonics of the LO signal to mix input signals, using phase-shifted LO signals weighted by specific factors to generate a high-order harmonic mixed signal, which reduces the required LO frequency and minimizes interference from lower and higher order harmonics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional down conversion is used to convert high frequency RF signal to lower frequency, then the implementation of receiver circuit is eased and digital processing is improved, but the local oscillator frequency must be very high which increases power consumption and design complexity
Solution Approach 1:
The patent changes the mixing parameter from fundamental frequency to high-order harmonic frequency. By using the N-th harmonic of a lower frequency LO signal, the patent achieves the equivalent effect of mixing with an N-times higher frequency, thereby reducing the actual LO frequency and power consumption while maintaining the desired down-conversion functionality
Solution Approach 2:
The patent creates a virtual high-frequency mixing effect by synthesizing the N-th harmonic signal from a lower frequency fundamental signal. Instead of directly generating and using a high frequency LO signal, the system copies the mixing function by using harmonic generation, achieving the same spectral translation effect with lower power consumption
2Adaptability or versatility
If the local oscillator frequency is increased to cover wide tuning range, then the system can handle higher RF frequencies, but the power consumption and design complexity increase significantly
Solution Approach 1:
The patent transforms the frequency parameter relationship by using harmonic multiplication. The system achieves wide tuning range adaptability by using a lower frequency LO whose N-th harmonic covers the required RF frequency range, thereby reducing LO design complexity while maintaining versatile frequency coverage
Solution Approach 2:
The patent introduces dynamic harmonic selection capability where the system can dynamically choose different harmonic orders (N-th harmonic) to match different RF frequency bands. This dynamic adaptation allows the same LO circuit to serve multiple frequency ranges by simply changing the harmonic mixing order, enhancing versatility without increasing hardware complexity
3Use of energy by stationary object
If high-order harmonic mixing is used to reduce LO frequency, then power consumption is reduced, but interference from lower and higher order harmonics must be managed
Solution Approach 1:
The patent extracts and isolates the desired N-th harmonic component from the mixed signal while removing unwanted lower and higher order harmonic components through filtering. The bandpass filter is specifically designed to pass only the frequency band containing the desired harmonic mixing product, thereby eliminating harmonic interference
Solution Approach 2:
The patent introduces a bandpass filter as an intermediary element between the mixer output and the subsequent processing stages. This filter acts as a mediator that selectively passes the desired harmonic mixing product while blocking unwanted harmonic components, thereby resolving the interference issue introduced by high-order harmonic mixing
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 approach lowers the VCO frequency requirement, leading to lower power consumption and improved system performance with enhanced signal-to-noise ratio (SNR) while maintaining a reduced tuning range.
Implementation Method 1
mixing the input signal with each of the plurality of phase-shifted local oscillation signals to generate a plurality of intermediate signals... the high-order harmonic mixed signal contains a lowest harmonic mixed signal and a plurality of higher harmonic mixed signals, wherein the lowest harmonic mixed signal has a first harmonic frequency at least three times the local oscillation frequency
Implementation Method 2
The RF input signal 105 is amplified by the variable-gain low-noise amplifier (LNA) 110. The amplified RF signal splits into two paths to feed two mixers 120a and 120b. The mixers receive in-phase 125a and quadrature phase 125b LO signals
Data Source
AI summary
A system and method for signal mixing using high-order harmonics of a local oscillation (LO) signal. In a radio frequency (RF) system, the input RF signal is converted to a lower frequency signal such as an intermediate frequency (IF) signal or a baseband signal for further processing. A voltage controlled oscillator (VCO) is often used to generate a VCO signal which is then divided down to provide the needed LO signals for down conversion. The present invention discloses a system and method for generating a composite harmonic signal based on a linear combination of divided down LO signals with specific phase shifts. Consequently a VCO signal with lower frequency can be used to conserve power. The composite harmonic signal is mixed with the input RF signal to generate a series of mixed signal including one associated with a high-order harmonic of the divided down LO signal. Systems to implement the high order harmonic mixing is also disclosed which comprises a plurality of mixer sections with configurable weighting factors. A combination circuit is used to combine the weighted mixed signals which contains a term corresponding the mixing of the input RF signal with a high order LO harmonic.