Switched Multiplexer Flat Group Delay Channelized Limiting
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Solution Overview
Problem
Conventional switched multiplexers suffer from high insertion loss, significant group-delay ripple, and inadequate high power signal limiting capabilities, often requiring non-reciprocal devices that introduce noise and inherent architecture losses, leading to the attenuation of all signals when faced with narrow band high power signals.
Innovation Solution
The implementation of intrinsically switched filters with power-dependent coupling elements and a resistively-terminated manifold structure that mimics an ideal transmission line, allowing for channelized limiting without affecting adjacent channels, and minimizing input impedance changes when switching filters on or off, thereby achieving flat passband insertion loss and group delay across contiguous bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional wide bandwidth limiters are used to attenuate high power signals, then high power signals are attenuated to prevent damage, but all signals including information-bearing signals are attenuated
Solution Approach 1:
The multiplexer divides the frequency spectrum into multiple discrete channels, each handled by independent filtering elements. This segmentation allows the limiter to affect only the specific frequency band containing the high power signal while leaving other channels unaffected, thus preventing information loss in adjacent bands.
Solution Approach 2:
The patent implements channelized limiting where each filter element provides limiting capability specific to its assigned frequency channel. This local quality approach ensures that high power signal attenuation is applied only where needed (in the affected channel) rather than globally across all frequencies, preserving information signals in other channels.
2Object-generated harmful factors
If passive switched multiplexer designs are used without amplifiers, then noise addition is avoided, but passband insertion losses exceed 10 dB due to architecture-related loss and dissipative losses
Solution Approach 1:
The patent employs dynamically controllable filter elements that can switch between different states (passive/active, connected/disconnected) based on signal conditions. This dynamic capability allows the system to optimize performance by activating elements only when needed, reducing continuous dissipative losses while maintaining low noise operation.
Solution Approach 2:
The invention changes the operational parameters of the filter elements, allowing them to transition between different impedance states and coupling configurations. By adjusting these parameters dynamically, the system minimizes insertion loss in the passband while maintaining the passive architecture that avoids noise addition.
3Ease of operation
If conventional switched multiplexer architectures are used, then channel switching is achieved, but group-delay ripple is quite high even in flat group-delay designs
Solution Approach 1:
The patent introduces intermediary elements (coupling structures, matching networks) between the switching elements and the filter channels. These intermediaries act as mediators that compensate for phase and delay variations introduced by the switching action, thereby reducing group-delay ripple while preserving channel switching capability.
Solution Approach 2:
The invention employs composite filter structures combining multiple resonator types and coupling mechanisms. This composite approach allows for finer control over the phase response and group delay characteristics, enabling the system to achieve lower group-delay ripple while maintaining effective channel switching.
4Reliability
If nonreciprocal devices such as amplifiers are used to prevent switching from affecting adjacent channels, then channel isolation is improved, but noise is added to the circuit
Solution Approach 1:
The patent replaces active electronic components (amplifiers) with passive electromagnetic coupling structures. By using carefully designed coupling elements and resonator configurations, the system achieves channel isolation through electromagnetic field management rather than active amplification, thereby eliminating the noise associated with amplifier operation while maintaining reliable channel separation.
Data Source
AI summary
Systems and method are provided for a switching circuit that enables attenuation of high power signals in relatively small band(s) without attenuating information in other bands. Embodiments of the present disclosure provide switching circuits with intrinsically switched filters that enable channelized limiting without affecting adjacent channels. Further, embodiments of the present disclosure provide a unique filter coupling topology that enables filters to be switched on or off without changing the input impedance of the filters.