Differential Transformer Signal Processing for Response Speed
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Solution Overview
Problem
Conventional electric micrometers with differential transformers face limitations in response speed due to low excitation frequencies, particularly at high resolutions like 1 nm, where the response speed is significantly slowed by residual ripple components and the inability to accurately adjust signals to zero, necessitating a reduction in response speed.
Innovation Solution
A signal processing apparatus and method that generates a high-frequency signal, divides it to match the excitation frequency, mixes and filters the output to remove low-frequency components, and uses phase-locked loops and phase shifters to synchronize phases, allowing for increased response speed without modifying the existing head.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the excitation frequency of the differential transformer is increased to improve response speed, then the response speed increases, but the head requires redesign and modification
Solution Approach 1:
The patent introduces an intermediary signal processing system consisting of a mixer, frequency divider, and phase-locked loop circuit. This intermediary system converts the low-frequency signal from the unchanged head into a high-frequency signal, thereby improving response speed without modifying the head itself. The frequency divider and phase-locked loop act as mediators that bridge the gap between the fixed head configuration and the desired high response speed.
Solution Approach 2:
The patent changes the operating parameters of the signal processing system by introducing high-frequency clock signals (e.g., 10 MHz) and using frequency division to generate appropriate driving frequencies for the differential transformer. This parameter change allows the system to achieve fast response speeds while keeping the head's physical structure unchanged, as the frequency transformation is accomplished through electronic parameter adjustment rather than mechanical modification.
2Measurement precision
If a low-pass filter is added to remove ripple components, then signal purity improves, but response speed decreases
Solution Approach 1:
Instead of using a low-pass filter to remove high-frequency ripple components (the conventional approach), the patent inverts the strategy by using a high-pass filter to remove low-frequency components and a band-pass filter to select the desired frequency range. This inversion allows the system to maintain fast response speeds while achieving signal purity, as the filtering is performed in the frequency domain through active signal generation and mixing rather than passive low-pass filtering.
Solution Approach 2:
The patent replaces the conventional mechanical/analog low-pass filter approach with an electronic signal processing system using mixers and phase-locked loop circuits. This substitution allows for more flexible frequency selection and signal processing, enabling the system to achieve both high response speed and signal purity through electronic frequency transformation rather than relying on the slow response characteristics of traditional low-pass filters.
3Speed
If the excitation frequency is increased to improve response speed, then response speed improves, but balance adjustment for capacitance and inductance becomes difficult
Solution Approach 1:
The patent uses an intermediary phase-locked loop circuit and frequency divider system that operates independently of the differential transformer's balance adjustment mechanisms. This intermediary system generates the high-frequency driving signals through electronic frequency division, allowing the system to achieve high response speeds without requiring re-adjustment of the transformer's capacitance and inductance balance, which are optimized for the original low-frequency operation.
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 enhances the response speed of measurement signals by a factor of 10 to 100, enabling faster data processing and improved resolution without altering the existing head configuration.
Implementation Method 1
a frequency divider which divides the high-frequency signal to generate a driving signal for the differential transformer
Implementation Method 2
a mixer which mixes an output from the frequency reduction means with an output from the differential transformer
Implementation Method 3
a high-pass filter or a band-pass filter which cuts a low-frequency component of an output from the mixer
Implementation Method 4
means which synchronously detects the output from the high-pass filter or the band-pass filter with the use of the high-frequency signal
Implementation Method 5
When a voltage is applied to the sensor coils 28 and 30 through an external oscillator 32, voltages E1 and E2 are generated at the ends of the sensor coils 28 and 30, respectively, as shown in FIG. 2 due to the impedance change of the sensor coils 28 and 30 according to the position of the core 26
Data Source
AI summary
A measuring apparatus employing a differential transformer includes a high-frequency oscillator which generates a high-frequency signal having a frequency higher than the excitation frequency of the differential transformer, a frequency divider which divides the high-frequency signal to generate a driving signal for the differential transformer, a multiplier or divider which reduces the frequency of the high frequency signal by the frequency of the driving signal, a mixer which mixes the output from the multiplier or the divider with the output from the differential transformer, a high-pass filter or a band-pass filter which cuts a low-frequency component of the output from the mixer, and a double balanced mixer which synchronously detects the output from the high-pass filter or the band-pass filter with the use of the high-frequency signal. With the use of the thus configured apparatus, an output signal having a fast response speed can be obtained through the use of an existing head having a low excitation frequency.