Acoustic Proximity Sensor Circuit Ringdown Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional acoustic distance measurement systems fail to detect objects in close proximity due to the 'ringdown' or 'reverberation' period of the transducer, which interferes with echo signal detection and can result in flawed or missed measurements, especially in scenarios with multiple reflections.
Innovation Solution
A semiconductor device with a close proximity zone flag circuit and time of flight circuit that processes signals to determine the validity of echoes during the reverberation period, allowing for accurate distance measurement by asserting flags and counting time of flight within specific thresholds, thereby overcoming the limitations of conventional systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the transducer quality factor is increased to improve transmission efficiency, then the reverberation period is extended, but this prevents detection of echo signals from close proximity objects
Solution Approach 1:
The patent segments the echo detection process into two distinct phases: reverberation period detection and post-reverberation echo detection. During the reverberation period, the system monitors for specific signal characteristics that indicate close proximity objects, then transitions to conventional echo detection after reverberation subsides. This segmentation allows the system to maintain high quality factor for efficient transmission while accurately detecting echoes from close objects that would otherwise be obscured.
Solution Approach 2:
The patent introduces an intermediary detection mechanism that operates during the reverberation period to identify close proximity objects. This intermediary system uses signal processing techniques to distinguish between reverberation signals and actual echo signals from close objects, acting as a mediator between the high quality factor transmission and accurate echo detection. The intermediary detection enables the system to overcome the natural limitation imposed by the reverberation period.
2Reliability
If the system waits for reverberation to subside before detecting echoes, then false detections are reduced, but echoes from close proximity objects are missed
Solution Approach 1:
The patent performs preliminary detection during the reverberation period by monitoring for specific signal characteristics that indicate close proximity objects. Instead of waiting for reverberation to completely subside, the system proactively identifies and flags potential close proximity echoes during the reverberation window. This preliminary action allows the system to capture time-critical information about close objects before the reverberation mask fades, eliminating the time loss associated with conventional wait-based approaches.
3Measurement precision
If conventional echo detection is used during reverberation, then close proximity objects can be detected, but false detections and measurement errors increase
Solution Approach 1:
The patent implements a dynamic detection strategy that adapts the detection threshold and processing mode based on the current signal environment. During the reverberation period, the system uses one set of detection parameters optimized for identifying close proximity objects, while transitioning to conventional parameters after reverberation subsides. This dynamic adaptation allows the system to maintain high detection precision for close objects while preserving overall measurement reliability by adjusting to changing signal conditions.
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
Enables reliable detection of objects in close proximity zones by distinguishing valid echoes from reverberation, improving the accuracy of distance measurements and preventing missed detections, even in situations with overlapping echoes.
Implementation Method 1
transmitting a short pulse of acoustic energy, creating a sound wave in the ambient air
Implementation Method 2
measuring the time it takes to receive an echo of the pulse, which indicates the distance to the object that reflected the acoustic pulse
Implementation Method 3
an electric signal is applied to an acoustic transducer to cause the operative part of the transducer to vibrate in correspondence with the electric signal
Implementation Method 4
During ringdown the frequency of the transducer vibration is at its natural or resonant frequency
Implementation Method 5
the transducer continues to vibrate during a period referred to as 'ringdown' or 'reverberation'
Data Source
AI summary
In embodiments a circuit provides a circuit for use in detecting close proximity objects in an acoustic distance sensing system. The circuit produces a close proximity zone flag when the time after transmitting an acoustic distance sensing pulse corresponds to the defined close proximity range. The circuit can also include a time of flight counter for determining the time of flight of a received echo. The circuit can further produce a close proximity time if flight valid flag indicating that echoes are being received in close proximity time frame.