Receiver-Path DC Offset Calibration Using Even Harmonic Detection
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Solution Overview
Problem
Existing electronic circuits face challenges in maintaining good performance due to DC offset, which can cause signal distortion, and current methods for offset compensation either increase circuit complexity or are inefficient and time-consuming.
Innovation Solution
A DC offset calibration device comprising a signal generation unit, a to-be-calibrated unit, a measurement unit, and a compensation unit, which measures even harmonics resulting from clipped signals to calculate and adjust for DC offset without requiring a measurement circuit on the transmission path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a DC offset measurement circuit is arranged in the signal transmission path, then DC offset can be measured and calibrated, but circuit complexity and circuit area increase
Solution Approach 1:
The patent introduces an intermediary approach by using the receiving path as a mediator to measure the DC offset of the transmission path. Instead of placing a measurement circuit directly in the transmission path, the system transmits a test signal through the transmission path, receives it through the receiving path, and measures the DC offset from the received signal. This intermediary measurement method achieves DC offset calibration without adding complexity to the transmission path circuit.
Solution Approach 2:
The receiving path is given a dual function: it not only performs its normal signal reception role but also serves as a measurement instrument for detecting DC offset in the transmission path. By making the receiving path multi-functional, the patent eliminates the need for a separate DC offset measurement circuit in the transmission path, thereby reducing overall circuit complexity while maintaining measurement capability.
2Measurement precision
If a DC offset measurement circuit is arranged in the signal transmission path, then DC offset can be measured and calibrated, but circuit area increases
Solution Approach 1:
The patent merges the DC offset measurement function with the existing receiving path components. Instead of adding a separate measurement circuit that would occupy additional area, the system combines the measurement functionality with the receiver's existing signal processing chain. The receiving path processes the transmitted test signal and extracts DC offset information, effectively merging two functions into one integrated path and reducing overall circuit area.
3Device complexity
If DC offset is adjusted manually, then no additional measurement circuit is needed, but the process is time consuming and DC offset may not be effectively eliminated
Solution Approach 1:
The patent implements an automated feedback mechanism for DC offset calibration. The system transmits a test signal, measures the DC offset from the received signal through the receiving path, computes the offset value, and automatically adjusts the transmission path components. This closed-loop feedback process eliminates manual adjustment, significantly reducing calibration time and ensuring accurate DC offset elimination while maintaining relative circuit simplicity.
Solution Approach 2:
The system performs self-calibration by automatically detecting and correcting its own DC offset without requiring external manual intervention. The receiving path measures the offset, the computation unit calculates the correction value, and the system automatically applies the correction to the transmission path. This self-service capability reduces calibration time and ensures effective DC offset elimination while keeping the circuit design relatively simple.
4Device complexity
If DC offset is adjusted manually, then no additional measurement circuit is needed, but DC offset may not be effectively eliminated
Solution Approach 1:
The automated feedback mechanism ensures accurate DC offset calibration by continuously measuring the actual offset through the receiving path and adjusting the transmission path until the offset is minimized. This feedback-controlled approach is more precise than manual adjustment because it uses actual measurement data from the receiving path to guide the correction process, ensuring effective DC offset elimination while maintaining relatively simple circuit architecture.
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
Reduces circuit area and manufacturing costs while effectively eliminating DC offset by utilizing the receiving path components for calibration, ensuring reduced signal distortion and improved circuit performance.
Implementation Method 1
The to-be-calibrated unit is coupled to the signal generation unit, and configured to receive the first signal and output a second signal accordingly. The second signal is a clipped signal.
Implementation Method 2
The receiving signal may comprise an even harmonic resulted from the clipped signal, and the measurement unit is configured to measure a magnitude of the even harmonic
Data Source
AI summary
A direct current (DC) offset calibration device and a method are used to calibrate a DC offset of a unit. The DC offset calibration device includes a signal generation unit, a to-be-calibrated unit, a measurement unit, and a compensation unit. The DC offset calibration method includes: using the to-be-calibrated unit to output a clipped signal resulting from a signal saturation effect; receiving a receiving signal correlated to the clipped signal, the receiving signal including an even harmonic resulting from the clipped signal; measuring a magnitude of the even harmonic to obtain a DC offset adjustment value accordingly; and adjusting the to-be-calibrated unit according to the DC offset adjustment value to calibrate the DC offset.