Phase-Encoded Continuous Wave Transmitter for Distance Measurement
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Solution Overview
Problem
Conventional distance measurement systems using pulsed transmission signals are complex, costly, and have high peak-to-average power ratios, limiting their accuracy and ability to detect multiple reflections.
Innovation Solution
A method that encodes a continuous wave carrier signal with a code representing a pulse in non-pulse form, such as a Gaussian noise-like sequence, allowing the system to operate as a pulsed system without altering the continuous wave nature, enabling high accuracy and multiple reflection detection while maintaining lower power requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pulsed transmission signals are used for distance measurement, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent uses a continuous wave signal that copies the essential information of a pulsed signal through phase encoding. Instead of generating actual pulses, the system encodes pulse-like information into a continuous wave using phase modulation, creating a simplified copy that maintains measurement precision while reducing hardware complexity
Solution Approach 2:
The patent transforms the transmission signal from a pulsed form to a continuous wave form with phase variations. By changing the parameter representation from time-domain pulses to phase-domain encoding, the system achieves equivalent measurement capability with simpler hardware requirements
2Measurement precision
If pulsed transmission signals are used, then distance measurement accuracy is improved, but power consumption increases
Solution Approach 1:
The patent changes the power consumption profile by transforming from pulsed high-power transmission to continuous low-power transmission with phase modulation. The continuous wave maintains constant lower power levels while encoding distance information through phase variations, eliminating the need for high peak power pulses
Solution Approach 2:
The system uses periodic phase modulation on a continuous wave carrier to encode pulse-like information. By applying periodic phase changes rather than actual periodic pulses, the system achieves the same information transfer with continuous low-power operation instead of intermittent high-power bursts
3Measurement precision
If conventional pulsed systems are used, then distance measurement is achieved, but ability to detect multiple reflections is limited
Solution Approach 1:
The continuous wave signal with phase encoding copies the information content of multiple pulses, allowing the system to distinguish and analyze multiple reflected signals. The phase-modulated continuous wave maintains the temporal information needed to identify multiple reflections while using simpler continuous transmission
Solution Approach 2:
The patent employs continuous transmission instead of intermittent pulsing, allowing uninterrupted monitoring of reflected signals. This continuous action enables the system to detect and analyze multiple reflections over time without the gaps between pulses that limit conventional systems
Data Source
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AI summary
Transmitter signals are modulated with one or more codes which may represent a pulse even though the code(s) are not shaped as pulses. The code(s) may be generated by defining a pulse by its Fourier components, and then adding random phases to the Fourier components. A time-domain signal may then be created, which may serve as the code to be modulated on a carrier wave. Upon reflection of the transmitter signal, the received signal may be processed by a receiver to recover the pulse. The time-of-flight of the transmitter signal can then be determined, enabling distance measurements to be made.