Signal Receiver Group Delay Compensation
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Solution Overview
Problem
Signal receivers face limitations in accurately processing wideband signals due to phase distortions introduced by non-linear phase responses of analog signal processing components, which result in non-uniform group delay and amplitude distortions, affecting the combination of signals with different frequencies.
Innovation Solution
A signal receiver system that includes an antenna interface, analog signal processing circuitry, sampling circuitry, a digital compensator, and a digital processor, with a calibration signal generator injecting a calibration signal to configure the digital compensator and processor to compensate for non-uniform group delay and amplitude distortions using Fourier transforms and FIR filters, ensuring accurate signal processing across multiple frequency bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If analog signal processing circuitry is used to condition received signals, then signal amplitude and frequency characteristics are improved, but non-linear phase response and non-uniform group delay are introduced
Solution Approach 1:
A digital compensator is introduced as an intermediary component between the analog signal processing circuitry and the digital processor. The digital compensator receives digitized signals, applies group delay compensation based on pre-calculated compensation values, and outputs corrected signals. This intermediary digital processing stage eliminates the phase distortion harmfully introduced by the analog circuitry without requiring redesign of the analog components themselves.
Solution Approach 2:
The system performs preliminary calibration by injecting calibration signals through the antenna interface, measuring the actual group delay characteristics of the analog circuitry, and pre-calculating compensation values before normal signal processing begins. This preliminary characterization of the analog circuitry's phase response enables the digital compensator to apply accurate correction during subsequent signal processing operations.
2Measurement precision
If calibration signals are injected to characterize system response, then compensation accuracy is improved, but average power levels must be controlled to avoid impacting gain control circuit settings
Solution Approach 1:
The calibration signal injection is performed periodically or at specific intervals rather than continuously. The system injects calibration signals during designated calibration periods to measure group delay characteristics, then switches to normal signal processing mode. This periodic calibration approach achieves accurate system characterization while minimizing the time-averaged power consumption and preventing continuous high-power calibration signals from affecting the automatic gain control circuit settings.
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 system effectively compensates for phase and amplitude distortions, enhancing the accuracy of signal processing and enabling precise combination of signals from various frequencies, thereby improving the overall performance of signal receivers in handling wideband signals.
Implementation Method 1
The digital compensator is configured in accordance with phase values produced by a Fourier transform of signals received by the digital compensator in response to injection of the calibration signal at the antenna interface, the Fourier transform producing the phase values for a plurality of frequencies corresponding to the orthogonal frequency components of the calibration signal
Data Source
Figure 1
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Figure 3A~3B
AI summary
A signal receiver (120) includes an antenna interface (204) for receiving signals from an antenna (202), analog signal processing circuitry (208-a, 208-b, 208-c) coupled to the antenna interface (204) for processing the received signals to produce filtered signals, sampling circuitry (210-a, 210-b, 210-c) to sample the filtered signals so as to produce digitized received signals, a digital compensator (212-a, 212-b, 212-c) to receive the digitized received signals and compensate for non-uniform group delay introduced by the analog signal processing circuitry (208-a, 208-b, 208-c) to produce compensated digitized received signals, and a digital processor (214) to process the compensated digitized received signals so as to produce a result.