Distance Sensor Voltage Dip Signal Dynamic Range
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Solution Overview
Problem
Existing distance-measuring sensors face challenges in accurately determining signal propagation time over a large dynamic range, particularly in optoelectronic systems, due to the limitations of current amplification methods which struggle with the 120 dB range and result in noise, interference, and reduced detection capability.
Innovation Solution
A distance-measuring sensor that uses an additional measurement channel based on a voltage drop in the bias unit, allowing indirect inference of the signal reception time, enabling the use of two complementary measurement channels to extend the dynamic range and improve signal processing without affecting the received signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a static amplification factor is used in the transimpedance amplifier, then the circuit design is simple, but the dynamic range is limited to approximately 30-40 dB
Solution Approach 1:
The patent implements dynamic gain adjustment by switching between multiple amplification stages with different gain factors (first amplification stage with gain G1, second amplification stage with gain G2). The system automatically selects the appropriate gain stage based on the input signal strength, enabling the amplifier to adapt to a wide dynamic range of approximately 120 dB while maintaining circuit feasibility.
2Adaptability or versatility
If the gain is dynamically adjusted from pulse to pulse, then the dynamic range is extended, but the response time of the system deteriorates considerably
Solution Approach 1:
The patent uses a pre-pulse sent before each measurement pulse to obtain information about the expected reception strength. This preliminary action allows the system to pre-adjust the appropriate amplification stage before the actual distance measurement pulse is processed, thereby extending the dynamic range while minimizing the impact on response time.
Solution Approach 2:
The system employs periodic pre-pulses sent at regular intervals before the measurement pulses. This periodic action enables the gain adjustment mechanism to be activated only when needed, maintaining a balance between extending the dynamic range and preserving the overall response time of the distance measurement system.
3Adaptability or versatility
If multiple amplification stages are used to cover the dynamic range, then the dynamic range is extended, but the individual channels influence each other causing increased noise and susceptibility to interference
Solution Approach 1:
The patent extracts and processes strong and weak signals through separate amplification stages. By routing signals through different gain stages based on their strength, the system prevents strong signals from overwhelming weak signals and reduces mutual interference between channels, thereby extending the dynamic range while maintaining signal integrity and reducing noise.
Solution Approach 2:
The patent introduces a signal detection and evaluation unit that acts as an intermediary between the multiple amplification stages. This unit detects the signal strength and automatically selects or switches between the first and second amplification stages, ensuring that only the appropriate stage processes each signal. This mediation prevents channel interference and maintains low noise levels while covering a wide dynamic range.
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 significantly expands the dynamic range for precise determination of signal reception time and amplitude, reducing amplification artifacts and noise, while maintaining the integrity of the received signal for further evaluation.
Implementation Method 1
the light signal is first converted into an electrical signal and amplified in an analogue electronic circuit. Since a photodetector generates a photocurrent
Implementation Method 2
a voltage drop in a bias unit of the receiver is measured and this signal is used for a time-of-flight measurement
Data Source
Figure 1~2
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AI summary
A distance-measuring sensor (10) for detecting and determining the distance of objects (20) in a monitoring area (18) is described. The sensor (10) comprises a transmitter (12) for emitting a transmit signal (16), a receiver (26) for generating a received signal from the transmitted signal (22) remitted in the monitoring area (18), and an evaluation unit (30) configured to determine the signal propagation time from the sensor (10) to the object (20). The receiver (26) includes a pre-tensioning unit (28). A voltage measuring unit (32) is connected to the pre-tensioning unit (28) to generate a voltage dip signal upon reception of a remitted transmitted signal (22), and the evaluation unit (30) is configured to determine the signal propagation time based on the voltage dip signal.