Superparamagnetic Measurement Device Using Dual-Frequency Mixing
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Solution Overview
Problem
Existing devices for measuring superparamagnetic materials face challenges such as high energy consumption, sensitivity to signal offsets, and electromagnetic interference, while also being costly and lacking robustness in signal-to-noise ratio and electromagnetic compatibility.
Innovation Solution
A device comprising four coils connected in series with specific current injection and detection mechanisms, utilizing direct and alternating currents at different frequencies to isolate a voltage component proportional to the superparamagnetic material's quantity, while minimizing interference and using commercially available components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional measurement devices are used, then measurement capability is achieved, but energy consumption is high
Solution Approach 1:
The patent applies periodic action by using alternating currents at two different frequencies (first frequency and second frequency) to excite the superparamagnetic material. This periodic excitation allows the measurement signal to be modulated at a mixing frequency that is the sum of the two input frequencies, enabling the system to distinguish the measurement signal from background noise and offsets while maintaining low energy consumption through efficient frequency domain separation.
2Measurement precision
If conventional measurement devices are used, then measurement is performed, but signal offsets affect the results
Solution Approach 1:
The patent uses frequency domain separation as an intermediary mechanism. By injecting two alternating currents at different frequencies and detecting the voltage component at the mixing frequency (sum of the two frequencies), the system creates a unique signal pathway that is insensitive to direct current offsets and low-frequency noise. The mixing frequency acts as a mediator that carries the measurement information while being separated from the harmful offset signals.
3Measurement precision
If conventional measurement devices are used, then measurement capability is provided, but signal-to-noise ratio is low
Solution Approach 1:
The patent changes the frequency parameter of the excitation signals to improve signal-to-noise ratio. By using two different frequencies for the alternating currents and detecting at the mixing frequency, the measurement signal is shifted to a frequency range where noise is minimized. This parameter change in the frequency domain allows the system to achieve high signal-to-noise ratio without requiring complex signal processing.
4Reliability
If conventional measurement devices are used, then measurement is performed, but electromagnetic interference reduces robustness
Solution Approach 1:
The patent uses periodic action with two different frequencies to create a measurement signal that is inherently robust against electromagnetic interference. The mixing frequency, being the sum of the two input frequencies, creates a unique spectral signature that is unlikely to coincide with common electromagnetic interference frequencies. This periodic excitation at multiple frequencies provides natural immunity against single-frequency electromagnetic interference.
5Ease of manufacture
If conventional measurement devices are used, then measurement function is provided, but device cost is high
Solution Approach 1:
The patent achieves high measurement precision with low device cost by using a multi-functional coil system. The same four coils are used for both generating the magnetic field through alternating current excitation and detecting the voltage component at the mixing frequency. This universal use of components eliminates the need for separate expensive detection coils and signal processing hardware, while the frequency domain separation technique provides high precision measurement capability.
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 device achieves low energy consumption, high signal-to-noise ratio, and robustness against electromagnetic interference, meeting EMC requirements and providing cost-effective measurements.
Implementation Method 1
four coils of electrical wire having identical or substantially identical respective geometries and electrical and electromagnetic properties, and these four coils being electrically connected in series
Implementation Method 2
A superparamagnetic material is a non-linear magnetic material that does not have hysteresis when the magnetic excitation that is applied to this material is varied periodically
Implementation Method 3
the quantity of the superparamagnetic material is determined from the extent of its capacity to produce an alternating voltage at the mixing frequency in at least some of the coils, due to the non-linearity of the superparamagnetic material
Data Source
AI summary
A device for measuring a quantity of a superparamagnetic material includes four coils (1-4) and a unit for injecting, into the coils, a direct current and two alternating currents of different frequencies. The quantity of superparamagnetic material is derived from an amplitude of a component at a mixing frequency, which frequency is a linear combination of the frequencies of the two alternating currents. The device is designed to reduce the influence of stray electromagnetic fields and inadvertent signal offsets on the measurement results. The device may advantageously be used for immunoassays.