Non-Magnetic-Core Band Rejection Filter for Harmonic Suppression
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Solution Overview
Problem
Magnetic-core inductors in band rejection filters used in satellite signal receivers can experience magnetic saturation when handling high power signals, leading to non-linear harmonic interference and reduced communication quality in home networks due to leaked signals in the 4 to 100 MHz frequency band.
Innovation Solution
A band rejection filter design utilizing non-magnetic-core inductors, such as ceramic-core or air-core inductors, in conjunction with capacitors, is implemented between the frequency down converter and the set-top box to filter out signals within the 4 to 100 MHz range, preventing magnetic saturation and harmonic interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If magnetic-core inductors are used in the band rejection filter, then the filter can effectively block signals in the 4 to 100 MHz frequency band, but magnetic saturation occurs when handling high power signals, generating non-linear harmonic interference
Solution Approach 1:
The patent changes the material parameter of the inductor from magnetic-core to non-magnetic-core (such as air-core or ferrite-core), which fundamentally alters the magnetic properties and eliminates magnetic saturation effects. This parameter change allows the inductor to handle high power signals without generating non-linear harmonic interference while maintaining the required filtering performance in the 4 to 100 MHz band.
2Ease of manufacture
If magnetic-core inductors are used in the low pass filter, then cost and size are reduced, but magnetic saturation generates non-linear effect causing harmonics in the 4 to 100 MHz frequency band
Solution Approach 1:
The patent changes the core material parameter from magnetic to non-magnetic, eliminating the magnetic saturation problem that causes harmonic interference. While non-magnetic-core inductors may have slightly different cost and size characteristics, they provide the critical advantage of linear operation at high power levels, preventing harmonics in the home network frequency band.
3Reliability
If a band rejection filter is added to filter out leaked signals, then communication quality of home network is improved, but magnetic saturation in the filter generates non-linear harmonic interference that affects communication quality
Solution Approach 1:
The patent changes the inductor core material from magnetic to non-magnetic in the band rejection filter, eliminating magnetic saturation effects. This ensures that the filter itself does not generate harmonic interference that would compromise the communication quality it is designed to protect, while maintaining effective signal rejection in the 4 to 100 MHz band.
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 use of non-magnetic-core inductors in the band rejection filter effectively reduces harmonics and maintains low insertion loss, ensuring high communication quality by preventing magnetic saturation and nonlinear harmonic interference, thus enhancing the transmission quality of satellite signals in home networks.
Implementation Method 1
The low pass filter includes a plurality of non-magnetic-core inductors coupled in a sequence between the first signal end and the second signal end, and a plurality of capacitors respectively coupled between an intersection of adjacent non-magnetic-core inductors of the plurality of non-magnetic-core inductors and a ground end
Data Source
AI summary
A band rejection filter capable of reducing harmonics includes a first signal end, a second signal end, a high pass filter coupled between the first signal end and the second signal end for performing high pass filtering on signals transmitted between the first signal end and the second signal end, and a low pass filter coupled between the first signal end and the second signal end for performing low pass filtering on signals transmitted between the first signal end and the second signal end. The low pass filter includes a plurality of non-magnetic-core inductors coupled in a sequence between the first signal end and the second signal end, and a plurality of capacitors respectively coupled between an intersection of adjacent non-magnetic-core inductors of the plurality of non-magnetic-core inductors and a ground end.