RF Balun Switching Circuit for Lower Intermodulation Distortion
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Solution Overview
Problem
Signal distortion and deterioration of characteristics occur in radio-frequency circuits due to large electric power applied to devices such as filters and switches.
Innovation Solution
A radio-frequency circuit design incorporating filters, amplifiers, switches, and baluns with specific coil connections to reduce power applied to switches, thereby minimizing signal distortion and temperature rise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If large electric power is applied to filters and switches to maintain signal strength, then the output signal level is improved, but signal distortion occurs and circuit characteristics deteriorate
Solution Approach 1:
The patent divides the radio frequency circuit into multiple independent branches with separate filters (first filter with first pass band, second filter with second pass band) and separate amplifiers (first amplifier, second amplifier). This segmentation allows each component to operate at lower power levels within its specific frequency range, reducing signal distortion while maintaining overall output signal strength through the combined effect of multiple branches.
Solution Approach 2:
The patent changes the operational parameters of filters and amplifiers by assigning different pass bands to different filters and using baluns to transform impedance and voltage levels. The first balun and second balun convert between balanced and unbalanced signals while adjusting voltage levels, allowing filters to operate at reduced power levels without compromising the overall output signal level.
2Power
If large electric power is applied to switches to maintain signal strength, then the output signal level is improved, but temperature rise occurs and characteristics deteriorate
Solution Approach 1:
The patent segments the signal path into multiple branches with separate switches (first switch, second switch) that operate in different frequency bands. Each switch handles only a portion of the total signal power, reducing the power dissipation and temperature rise in individual switches while maintaining the overall output signal level through combined operation of all branches.
Solution Approach 2:
The patent employs baluns that dynamically transform signal characteristics, converting between balanced and unbalanced configurations and adjusting voltage levels. This dynamic transformation allows switches to operate at lower voltage and power levels in certain configurations, reducing heat generation while maintaining signal integrity and output level.
3Power
If large electric power is applied to filters to maintain signal strength, then the output signal level is improved, but intermodulation distortion increases
Solution Approach 1:
The patent divides the filtering function into multiple independent filters, each handling a specific pass band. The first filter processes signals in its designated frequency range and the second filter processes signals in its own frequency range, preventing intermodulation distortion that would occur if a single filter handled all frequencies at high power levels.
Solution Approach 2:
The patent changes the operational parameters of filters by assigning different pass bands and using baluns to transform voltage and impedance levels. This parameter transformation allows filters to operate at reduced power levels within their specific frequency ranges, minimizing intermodulation distortion while maintaining overall output signal strength through the combined effect of multiple filtered branches.
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 design effectively suppresses signal distortion and deterioration of radio-frequency circuit characteristics by reducing power to switches and filters, enhancing performance and reducing intermodulation distortion.
Implementation Method 1
The first balun has a first coil and a second coil... In the first balun, a first end of the first coil is connected to a terminal of the input terminal and the output terminal of the amplifier
Data Source
AI summary
In a first balun of a radio-frequency circuit, a first end of a first coil is connected to an amplifier, and a second end of the first coil is connected to a ground. In the first balun, a first end of a second coil is connected to a first switch, and a second end of the second coil is connected to a second switch. In a second balun, a first end of a third coil is connected to the first end of the second coil via the first switch, and a second end of the third coil is connected to the second end of the second coil via the second switch. In the second balun, a first end of a fourth coil is connected to a filter, and a second end of the fourth coil is connected to the ground.