Radar Sensor DC Offset Compensation Using Segmented Circuit
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Solution Overview
Problem
Existing radar sensors face challenges in minimizing noise and power loss due to the resistances required for DC voltage compensation in the signal path, which affect signal quality and radar location accuracy.
Innovation Solution
The introduction of a coarse compensation device in the transmitting and receiving part, utilizing existing load resistances in the mixer to address constant DC voltage components, allowing for a low-noise fine compensation device with reduced resistance values, thereby minimizing noise and power loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If resistance values are increased to reduce noise in the compensation device, then noise component decreases, but power loss increases
Solution Approach 1:
The compensation device is divided into two independent parts: a coarse compensation device with high resistance values for constant DC voltage components (prioritizing noise reduction) and a fine compensation device with low resistance values for time-variable DC voltage components (prioritizing speed and power consumption). This segmentation allows each part to be optimized for its specific function without compromising the other.
Solution Approach 2:
Different resistance values are assigned to different parts of the compensation device based on local requirements. The coarse compensation device uses high resistance values where noise reduction is critical, while the fine compensation device uses low resistance values where fast response and low power consumption are critical. Each part has optimized local properties suited to its specific function.
2Loss of energy
If resistance values are decreased to reduce power loss in the compensation device, then power loss decreases, but noise component increases
Solution Approach 1:
The compensation device is divided into two independent parts: a coarse compensation device with high resistance values for constant DC voltage components (prioritizing noise reduction) and a fine compensation device with low resistance values for time-variable DC voltage components (prioritizing speed and power consumption). This segmentation allows each part to be optimized for its specific function without compromising the other.
Solution Approach 2:
Different resistance values are assigned to different parts of the compensation device based on local requirements. The coarse compensation device uses high resistance values where noise reduction is critical, while the fine compensation device uses low resistance values where fast response and low power consumption are critical. Each part has optimized local properties suited to its specific function.
3Manufacturing precision
If DC voltage compensation is implemented before amplification, then signal distortion is reduced, but noise from compensation resistors is amplified
Solution Approach 1:
The compensation device is divided into two independent parts: a coarse compensation device with high resistance values for constant DC voltage components (prioritizing noise reduction) and a fine compensation device with low resistance values for time-variable DC voltage components (prioritizing speed and power consumption). This segmentation allows each part to be optimized for its specific function without compromising the other.
Solution Approach 2:
Different resistance values are assigned to different parts of the compensation device based on local requirements. The coarse compensation device uses high resistance values where noise reduction is critical, while the fine compensation device uses low resistance values where fast response and low power consumption are critical. Each part has optimized local properties suited to its specific function.
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
This approach effectively suppresses DC voltage components with low current levels and power loss, maintaining signal quality and radar accuracy without increasing noise components in the baseband signal.
Implementation Method 1
The radar echo received by the antenna is mixed with a portion of this transmitted signal in the mixer so that a baseband signal is obtained whose frequency corresponds to the frequency difference between the transmitted and received signals
Implementation Method 2
The coarse compensation device is formed by current sources in the transmitting and receiving part and is designed to compensate for constant portions of the DC voltage offset over time in the transmitting and receiving part using working resistances of the mixer
Implementation Method 3
the fine compensation device in the evaluation circuit... uses current sources and resistors arranged in the signal path to compensate for the DC voltage in the baseband signal
Data Source
Figure 1~2
AI summary
The invention relates to a radar sensor for motor vehicles, comprising a sending and receiving part (10) that has a mixer (20) for mixing a sent signal with a received signal, an analyzing circuit (12) that is connected to an output of the mixer (20) via a direct current coupling device (22), and a compensating device (24, 30) for compensating for a direct current offset in the output signal of the mixer (20). The radar sensor is characterized in that the compensating device is divided into a course compensating device (30) in the sending and receiving part (10) and a fine compensating device (24) in the analyzing circuit (12).