IQ Template Delay Calibration for Precise Impulse Distance Measurement
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Solution Overview
Problem
Existing distance measuring technologies face challenges in accurately processing impulse signals to determine the location of a target, particularly in maintaining a precise phase difference between in-phase (I) and quadrature (Q) template signals.
Innovation Solution
A distance measuring apparatus that includes a digital-to-time converter (DTC), in-phase (I) and quadrature (Q) template generation parts, and correlators to process impulse signals. The apparatus uses a signal delay unit with buffers and controllable delay units to ensure a 90-degree phase difference between the I and Q template signals, allowing for precise distance measurement and control of the phase difference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a signal delay unit with buffers and controllable delay units is used to ensure 90-degree phase difference between I and Q template signals, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The signal delay unit is divided into multiple buffers connected in cascade, with controllable delay units inserted between them. This segmentation allows independent control of delay stages while maintaining overall phase precision, resolving the contradiction by breaking down the complex delay control into manageable segments.
Solution Approach 2:
The controllable delay units are configured in advance to provide predetermined delay amounts that establish the 90-degree phase difference between I and Q signals. By pre-configuring the delay characteristics, the system achieves precise phase control without requiring complex real-time adjustments, thus improving measurement precision while managing device complexity.
2Speed
If impulse signals are used for distance measurement, then measurement speed is improved, but measurement precision deteriorates due to difficulty in accurately determining target location
Solution Approach 1:
Template signals are introduced as intermediary reference signals that correlate with the received impulse signal. By comparing the received signal against known templates with precise phase relationships, the system can accurately determine target location from the impulse signal returns, thus maintaining high measurement speed while improving precision through the template correlation process.
Solution Approach 2:
The system utilizes phase as a key parameter to encode distance information in the impulse signal measurements. By measuring phase differences between I and Q channel correlations with template signals, the system achieves precise distance measurement from fast impulse signals, converting the speed advantage of impulse signaling into precise measurements through phase parameter extraction.
Data Source
AI summary
A distance measuring apparatus includes: a digital-to-time converter (DTC) configured to receive a clock signal and output a pulse corresponding to a provided code; an in-phase (I) template generation part configured to be triggered by the pulse output from the DTC to generate an I template impulse signal; a quadrature (Q) template generation part configured to be triggered by the pulse output from the DTC to generate a Q template impulse signal; and an I correlator configured to perform demodulation with the signal reflecting off the target and the I template impulse signal, and a Q correlator configured to perform demodulation with the signal reflecting off the target and the Q template impulse signal, wherein the distance measuring apparatus converts a result of demodulation into a digital code to measure the distance to the target.