Differential Amplifier Filters for Wider Even-Harmonic Suppression
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Solution Overview
Problem
Existing differential amplification circuits have limitations in frequency characteristics of their harmonic reduction filters, necessitating improvements for a wider frequency range.
Innovation Solution
The implementation of first and second filters with subtly different resonant frequencies, connected to a differential amplifier, to reduce even harmonics, where the center frequency of the first filter is lower and the second filter is higher than the even harmonic, allowing for overlapping frequency ranges of reduced pass levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single filter is used to reduce harmonics, then the filter structure is simple, but the frequency range where harmonics are reduced is limited
Solution Approach 1:
The single filter is divided into two separate filters with different center frequencies. The first filter has a center frequency lower than the even harmonic frequency, and the second filter has a center frequency higher than the even harmonic frequency. This segmentation allows each filter to target specific frequency ranges, thereby extending the overall frequency range where harmonics are reduced while maintaining manageable complexity in each individual filter.
2Measurement precision
If the center frequency of the filter is set exactly at the even harmonic frequency, then the harmonic reduction is maximized at that frequency, but the frequency range coverage is narrow
Solution Approach 1:
Different parts of the frequency spectrum are assigned to different filters with locally optimized center frequencies. The first filter is optimized for frequencies below the even harmonic, while the second filter is optimized for frequencies above the even harmonic. This local quality approach ensures that each filter operates at peak effectiveness for its designated frequency range, thereby achieving both high harmonic reduction effectiveness and broad frequency range coverage when the filters are combined.
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 configuration extends the frequency range where harmonic reduction occurs, achieving a wider and more effective suppression of harmonics compared to using a single resonant circuit.
Implementation Method 1
first and second filters configured to reduce level of an even harmonic included in output from the differential amplifier. The first and second filters are connected to output of the differential amplifier. A center frequency of the first filter is lower than a center frequency of the even harmonic. A center frequency of the second filter is higher than the center frequency of the even harmonic.
Data Source
AI summary
A differential amplification circuit includes a differential amplifier configured to output a signal including harmonics and first and second filters configured to reduce level of an even harmonic included in output from the differential amplifier. The first and second filters are connected to output of the differential amplifier. The first filter includes a resonant circuit composed of a capacitor and an inductor and a resonant circuit composed of a capacitor and the inductor. The second filter includes a resonant circuit composed of a capacitor and an inductor and a resonant circuit composed of a capacitor and the inductor. A center frequency of the first filter is lower than a center frequency of the even harmonic. A center frequency of the second filter is higher than the center frequency of the even harmonic.