Programmable Delay Line Calibration for Drift-Stable Radar Timing
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Solution Overview
Problem
Existing radar systems face challenges in providing reliable and efficiently tuned delayed signals due to temperature and fabrication variations, requiring precise adjustments that are difficult to achieve with analog circuits.
Innovation Solution
The use of a digitally programmable delay line and calibration techniques involving multiple known delays to adjust and stabilize the delayed signal, allowing for precise calibration and efficient tuning of delay points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If analog circuits with dual-ramp mode are used to generate trigger signals, then delay control is achieved, but the system performance varies with temperature and age, and tuning is difficult
Solution Approach 1:
The patent replaces the mechanical analog circuit system with a digital system. Specifically, it substitutes the analog dual-ramp circuit with a digitally controlled delay line and phase-locked loop, eliminating the temperature and age sensitivity inherent in analog components while enabling precise digital tuning of delay parameters
Solution Approach 2:
The patent changes the operating parameters from continuous analog values to discrete digital values. By using a digitally controlled delay line with programmable delay taps and a phase-locked loop with digital frequency control, the system achieves stable delay characteristics that can be precisely adjusted through digital parameter setting rather than mechanical potentiometer adjustment
2Ease of manufacture
If analog comparator circuits are used to generate pulses, then trigger signals are produced, but fabrication variations cause intrinsic delay differences
Solution Approach 1:
The patent replaces the analog comparator circuit with a digital logic-based phase detector and counter system. This substitution eliminates the fabrication variation sensitivity of analog comparators, as digital logic circuits have threshold-based operation that is less sensitive to manufacturing tolerances, thereby improving delay consistency across different devices
Solution Approach 2:
The patent introduces a phase-locked loop with feedback control that continuously monitors and adjusts the delay timing. The phase detector compares the actual delay with the target delay and adjusts the delay line control words accordingly, compensating for any fabrication variations and ensuring consistent delay performance
3Ease of operation
If potentiometer adjustment is used for calibration, then tuning is possible, but precision adjustment during operation is difficult
Solution Approach 1:
The patent replaces mechanical potentiometer adjustment with digital programming of delay parameters. The delay line is controlled by digital control words that can be precisely set and changed via software or control interfaces, enabling both easy operation and high precision delay adjustment during system operation
Solution Approach 2:
The patent makes the delay parameters dynamically adjustable through digital control. Instead of fixed mechanical settings, the delay line can be reconfigured in real-time by changing digital control words, allowing the system to adapt delay values dynamically during operation without physical adjustment
Data Source
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AI summary
A variable delay apparatus comprises a calibrating unit receiving a signal from a variable delay unit (101) and from a plurality of fixed delay sources (401, 402, 403), the calibrating unit comparing the signal from the variable delay unit (101) with a plurality of signals from the fixed delay sources (401, 402, 403) to control operation of the variable delay unit (101) over a delay range independently of environmentally-induced drift.