RF Band Pass Filter Feedback Control for Receiver Linearity
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Solution Overview
Problem
Designing band-pass filters (BPFs) that accurately center their pass-band at the carrier frequency of the signal of interest is challenging, as widening the bandwidth to achieve this also allows undesirable signals to pass through, reducing the linearity and signal-to-noise ratio of wireless receivers.
Innovation Solution
A wireless receiver system that includes a band-pass filter module with an input for a pilot signal, an output for generating a signal based on the pilot signal, and a control input for adjusting the center frequency, using a control module to determine energy and generate control signals to align the center frequency with the signal of interest, thereby optimizing the pass-band alignment and reducing distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the bandwidth of the BPF is increased to center the pass-band at the carrier frequency, then the pass-band alignment is improved, but the linearity of the receiver deteriorates due to increased passage of undesirable signals
Solution Approach 1:
The patent implements feedback control by monitoring the output signal of the BPF and adjusting the center frequency accordingly. A control system detects the carrier frequency of the signal of interest and dynamically adjusts the BPF center frequency to maintain optimal alignment, thereby achieving precise pass-band centering without permanently widening the bandwidth that would allow harmful signals to pass through.
Solution Approach 2:
The patent dynamically changes the center frequency parameter of the BPF based on detected carrier frequency information. By adjusting this parameter in response to signal conditions rather than using a fixed wide bandwidth, the system achieves accurate pass-band alignment while maintaining narrow bandwidth to preserve receiver linearity.
2Ease of operation
If the bandwidth of the BPF is increased to achieve better pass-band centering, then the ease of operation is improved, but the signal-to-noise ratio deteriorates due to increased noise passage
Solution Approach 1:
The system uses feedback from signal detection to automatically adjust the BPF center frequency, making the operation easy while maintaining narrow bandwidth. The control system continuously monitors the signal and adjusts parameters accordingly, achieving both ease of operation and high signal-to-noise ratio without the need for manually widening the bandwidth.
Solution Approach 2:
The BPF system performs self-adjustment by detecting its own operating conditions and automatically tuning the center frequency to match the carrier frequency. This self-service capability provides ease of operation while maintaining optimal signal-to-noise ratio through precise, automatic bandwidth management without requiring manual intervention to widen the bandwidth.
3Ease of operation
If the pass-band bandwidth is widened to mitigate centering challenges, then the ease of operation is improved, but the distortion increases reducing receiver linearity
Solution Approach 1:
The patent employs feedback control where the system monitors the signal passing through the BPF and adjusts the center frequency to maintain precise alignment with the carrier frequency. This feedback mechanism provides ease of operation by automatically handling centering while maintaining narrow bandwidth to prevent signal distortion and preserve receiver linearity.
Solution Approach 2:
The system dynamically changes the center frequency parameter based on detected signal characteristics rather than using a fixed wide bandwidth setting. This parameter adjustment approach achieves easy pass-band centering alignment while maintaining narrow bandwidth to minimize distortion and preserve signal integrity.
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 solution effectively centers the pass-band of the BPFs, maximizing linearity and signal-to-noise ratio by ensuring the pass-band is aligned with the signal of interest, while minimizing the passage of undesirable signals, thus enhancing the performance of wireless receivers.
Implementation Method 1
a band-pass filter module that includes an input for receiving a first pilot signal, an output that generates a first signal based on the first pilot signal
Implementation Method 2
A control module determines the energy of the first signal, generates a control signal based on the energy
Data Source
AI summary
A wireless receiver comprises a band-pass filter module that includes an input for receiving a first pilot signal, an output that generates a first signal based on the first pilot signal, and a control input for adjusting a center frequency of the band-pass filter module. A control module determines the energy of the first signal, generates a control signal based on the energy, and communicates the control signal to the control input of the band-pass filter module.