Multipath Power Meter for Low-Frequency Signal Detection
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Solution Overview
Problem
Conventional power meters face challenges in measuring low-frequency signals due to high-pass behavior, leading to measurement deviations and prolonged measurement times, especially when dealing with DC voltage and low-frequency signals.
Innovation Solution
A power meter with a multipath detector comprising two detector elements, where the sum and difference of their output voltages are calculated to separate common-mode and differential-mode components, allowing for accurate power measurement across a wide frequency range, including DC, by exploiting the properties of high-frequency detector elements and using a digital calculation unit for compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a small time constant is used in the detector element, then the dynamic response is improved, but the lower cut-off frequency increases making low-frequency measurement impossible
Solution Approach 1:
The patent divides the measurement task into two separate detector elements with different time constants. The first detector element has a small time constant for high-frequency measurements, while the second has a large time constant for low-frequency measurements. This segmentation allows each detector to be optimized for its specific frequency range without compromise.
Solution Approach 2:
The patent dynamically switches between two detector elements based on the input signal frequency. A frequency detection unit identifies the signal frequency, and a switching unit selects the appropriate detector element, enabling the system to adapt its time constant characteristic to match the measurement requirements.
2Measurement precision
If a large time constant is used to achieve low cut-off frequency, then low-frequency measurement is enabled, but the video bandwidth decreases and measurement time increases
Solution Approach 1:
The measurement function is segmented across two detector elements with different time constants. The first detector handles high-frequency signals with fast response, while the second detector handles low-frequency signals with slow response. This eliminates the need to use a large time constant for all frequency ranges.
Solution Approach 2:
The system dynamically selects the appropriate detector element based on signal frequency, enabling fast measurement for high-frequency signals and accurate low-frequency measurement only when needed, thus optimizing overall measurement productivity.
3Device complexity
If a single detector element is used, then the device complexity is reduced, but the frequency measurement range is limited
Solution Approach 1:
The patent creates a universal power measurement system that can accurately measure across a wide frequency range from DC to high frequencies. This is achieved by combining multiple detector elements with different time constants and using a switching mechanism, allowing a single system to perform multiple frequency range measurements.
Solution Approach 2:
The system uses dynamic switching between detector elements to adapt to different frequency ranges, enabling the detector structure to function universally across DC to high frequencies rather than being fixed for a single frequency range.
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 enables rapid response to changing envelope powers, accurate detection of low-frequency signals, and reduced measurement times, maintaining high sensitivity and accuracy without noise restrictions, allowing for a seamless transition between low-frequency and high-frequency measurements.
Implementation Method 1
In the case of the diode-based power sensors, a squaring of the signal voltage is achieved on the basis of the nonlinear characteristic of the diode
Implementation Method 2
the time constant is the product of the zero-point resistance R0 of the diode and the capacitance C of the charging capacitor of the detector element
Data Source
AI summary
The invention relates to a power meter with a two-path or multipath detector comprising at least two detector elements. Each detector element generates an output voltage. In order to detect an electrical power of an alternating electrical input signal, the sum and the difference of the output voltages of the detector elements are formed separately from one another.