Double Phase-Matched Intermodulation Cancellation
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Solution Overview
Problem
Intermodulation products generated by passive devices in electronic systems, particularly communication systems, pose a challenge due to their proximity to the original signal frequencies, making them difficult to separate using conventional filtering methods, which often result in high insertion loss and additional intermodulation generation.
Innovation Solution
The use of phase shifters to cancel specific intermodulation products by providing carefully selected phase shifts through multiple passive devices, ensuring that upper or lower intermodulation products between input and interfering signals are eliminated without the need for high insertion loss filters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional filtering methods are used to separate intermodulation products from original signals, then signal separation is attempted, but insertion loss increases and additional intermodulation is generated
Solution Approach 1:
The patent uses the harmful intermodulation products themselves as the cancellation mechanism. By generating additional intermodulation products through a second passive device that are equal in magnitude but opposite in phase (180 degrees) to the original intermodulation products, the harmful effects are converted into a beneficial cancellation effect. The intermodulation products that were previously harmful are now used to nullify each other, reducing the net intermodulation distortion without requiring high insertion loss filters.
2Measurement precision
If conventional filtering methods are used to separate intermodulation products from original signals, then signal separation is attempted, but additional intermodulation products are generated
Solution Approach 1:
The patent transforms the problematic intermodulation products into a solution by using them for cancellation. The second passive device generates intermodulation products that are deliberately designed to be equal in magnitude but opposite in phase to the original intermodulation products. This converts the harmful intermodulation phenomenon into a beneficial cancellation mechanism, where the intermodulation products nullify each other rather than adding to the distortion.
Solution Approach 2:
The patent applies preliminary anti-action by pre-generating cancellation signals through the second passive device before the intermodulation products reach the output. The phase shifters are configured to create intermodulation products with 180-degree phase opposition in advance, so that when these cancellation signals combine with the original intermodulation products at the output, the harmful effects are neutralized before they can cause additional distortion or interference.
3Object-generated harmful factors
If phase shifters are used to cancel intermodulation products, then intermodulation reduction is achieved, but device complexity increases
Solution Approach 1:
The patent utilizes parameter changes by adjusting the phase shifts of the phase shifters to achieve the desired 180-degree phase opposition for intermodulation cancellation. By changing the phase parameter of the signals passing through the passive devices, the system can dynamically control the cancellation effect. The phase shifters are configured to introduce specific phase delays that transform the intermodulation products into their opposite phase equivalents, enabling cancellation without requiring complex active components.
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 effectively reduces or eliminates intermodulation products, improving signal integrity by maintaining signal power while minimizing interference, even when intermodulation frequencies are close to the desired signal frequencies, thus enhancing the performance of communication systems without incurring significant insertion loss.
Implementation Method 1
a plurality of phase shifters each configured to provide a corresponding phase shift
Implementation Method 2
the phase shifts are selected to cancel one of an upper or lower intermodulation product
Data Source
AI summary
An apparatus includes: a first apparatus port receiving a first signal having a first frequency; a second apparatus port outputting the first signal having the first frequency; a first passive device connected between the first and second apparatus ports; a second passive device connected between the first and second apparatus ports; a plurality of phase shifters each providing a corresponding phase shift, wherein at least one of the phase shifters provides its phase shift in a first signal path between the first and second apparatus ports through the first passive device, and wherein at least another phase shifter provides its phase shift in a second signal path between the first and second apparatus ports through the second passive device. The phase shifts are selected to cancel an upper or lower intermodulation product between the first signal and a second signal having a second frequency received at the second apparatus port.