Distributed Noise Shaping With Active Ladder Networks for Wide Bandwidth
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional noise shaping circuits, such as phase-locked loops and delta-sigma modulators, face limitations in achieving effective noise shaping over wide bandwidths and high frequencies due to intrinsic capacitance issues, which affect their ability to attenuate unwanted noise without impacting desired signals.
Innovation Solution
A distributed modulator using active ladder networks with reactive impedance segments forms controlled-impedance transmission channels to generate feedback filter responses, overcoming the bandwidth limitations of conventional methods by combining active devices with discrete inductors and alleviating gain-bandwidth dependencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional noise shaping circuits (phase-locked loops, delta-sigma modulators) are used, then noise attenuation in a particular frequency band is achieved, but the bandwidth is limited and high frequency operation is affected by intrinsic capacitance
Solution Approach 1:
The circuit is divided into multiple distributed gain cells (first gain cell, second gain cell, etc.) connected in a chain, where each cell processes a portion of the signal. This segmentation allows the overall circuit to achieve wide bandwidth operation while maintaining noise shaping performance, as each individual cell operates at lower frequencies where intrinsic capacitance is less problematic.
Solution Approach 2:
The patent transitions from conventional single-stage noise shaping circuits to a distributed multi-stage architecture that operates in the spatial dimension (multiple cells along a chain). This dimensional transformation enables the circuit to achieve both high frequency operation and effective noise attenuation by distributing the processing function across multiple locations.
2Speed
If conventional noise shaping circuits operate at high frequencies, then bandwidth is increased, but intrinsic capacitance degrades performance
Solution Approach 1:
By segmenting the high-frequency signal processing across multiple distributed gain cells, each cell experiences reduced signal frequency components due to the distributed nature of the circuit. This segmentation isolates each cell from the full impact of intrinsic capacitance, maintaining performance stability at high operating frequencies.
Solution Approach 2:
The distributed ladder network acts as an intermediary structure that couples the gain cells together. This intermediary architecture provides controlled impedance matching and signal distribution that reduces the direct impact of intrinsic capacitance on individual cells, thereby maintaining performance stability.
3Measurement precision
If feedback is used to attenuate noise, then unwanted signal impairments are filtered, but the circuit complexity increases
Solution Approach 1:
The patent combines multiple functions (noise shaping, feedback processing, and signal distribution) into a single distributed ladder network structure. By merging these functions into one integrated architecture rather than separate circuits, the overall device complexity is reduced while maintaining signal quality improvement.
Solution Approach 2:
The distributed ladder network serves multiple functions simultaneously: it provides feedback paths for noise shaping, distributes signals to multiple gain cells, and maintains controlled impedance throughout the circuit. This multi-functionality reduces the need for separate dedicated circuits for each function, thereby reducing overall complexity.
Data Source
Figure 1A
Figure 1B
Figure 2A~2B
AI summary
Provided are, among other things, systems, apparatuses methods and techniques for attenuating the level of unwanted noise and/or distortion in a particular frequency band, without similarly attenuating the level of a desired signal in the same frequency band. One such apparatus includes a distributed network comprising a plurality of reactive impedance segments and gain cells that form transmission paths, over which continuous and quantized versions of an input signal propagate before combining with the input signal itself.