Twin-T Receiver Filter Reconfiguration for Aliasing Rejection
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Solution Overview
Problem
Wireless communication devices face challenges in managing power efficiency and signal processing complexity, particularly with the integration of millimeter wave technology, where aliasing signals from low sampling frequency ADC converters interfere with communication signals in multi-downlink pipe systems.
Innovation Solution
A reconfigurable filter apparatus with a twin-T network and switchable configurations is employed in the receive path, incorporating high frequency real pole circuitry and programmable gain amplifiers to suppress aliasing signals and improve notch rejection at aliasing frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a low sampling frequency ADC converter is used to reduce power consumption, then power efficiency is improved, but aliasing signals interfere with communication signals
Solution Approach 1:
The patent converts the harmful aliasing signals into a beneficial design constraint by designing a notch filter specifically targeted at aliasing frequencies. The twin-T network is configured to create transmission zeros at these frequencies, effectively transforming the harmful interference into a defined filtering requirement that improves overall system performance.
Solution Approach 2:
The patent introduces a notch filter with twin-T network as an intermediary component between the ADC converter and the signal processing chain. This intermediary actively suppresses aliasing frequencies before they can interfere with communication signals, allowing the system to operate with lower sampling frequencies while maintaining signal integrity.
2Reliability
If complex signal processing is implemented to handle millimeter wave frequencies, then communication performance is improved, but device complexity increases
Solution Approach 1:
The patent segments the signal processing function by separating the aliasing suppression task from the main communication signal processing chain. The notch filter with twin-T network handles specifically the aliasing frequency rejection, while other processing stages focus on communication performance, thereby reducing overall system complexity through functional decomposition.
Solution Approach 2:
The patent changes the frequency domain characteristics of the signal by introducing transmission zeros at aliasing frequencies through the twin-T network. This parameter change in the frequency response allows the system to maintain reliable communication performance while using simpler, lower sampling frequency ADC converters.
3Object-affected harmful factors
If filtering complexity is increased to suppress aliasing signals, then aliasing rejection is improved, but power consumption and device complexity increase
Solution Approach 1:
The patent merges the aliasing suppression function with the existing communication signal filtering requirements by designing a reconfigurable filter that can operate in multiple modes. The same filter structure handles both communication band filtering and aliasing frequency rejection, eliminating the need for separate filtering stages and reducing overall device complexity.
Solution Approach 2:
The patent implements a reconfigurable filter with dynamic switching capability that can adapt its transfer function based on operating conditions. The filter dynamically reconfigures between different modes (e.g., Rauch filter, PGA configuration) to optimize performance for different communication bands while maintaining effective aliasing suppression, thereby avoiding the need for complex fixed-structure filters.
Data Source
AI summary
Aspects described herein include devices and methods for a reconfigurable multi-feedback filter for wireless receivers. In one aspect, a device may include a signal input node, a signal output, and an amplifier having an amplifier output, a negative input, and a positive input. The positive input is coupled to a reference voltage, and the amplifier output is coupled to the signal output. The device may further include a twin-T network in a feedback path coupled from the amplifier output to the negative input, where the twin-T network comprises a first capacitor and a second capacitor serially coupled between the amplifier output and the negative input of the amplifier, where the first capacitor and the second capacitor are connected via a first node, and where the signal input node is coupled to the first node.