Pulse Position Modulation Circuit With DLL-Stabilized Pulse Width
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Solution Overview
Problem
Existing pulse-position modulation circuits face challenges in controlling the pulse width of the modulated signal due to performance variations and temperature changes, which affects the frequency spectrum of wirelessly transmitted signals.
Innovation Solution
A pulse-position modulation circuit is designed with a delay locked loop circuit and multiple impulse generation circuits, where differential signals with phase differences are used to generate pulses with controlled pulse widths, and a selection circuit selects the appropriate pulse based on an input signal, stabilizing the pulse width through precise phase control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional pulse generation circuit with delay circuits and logic circuits is used, then pulse generation is achieved, but pulse width fluctuates due to performance variations and temperature changes
Solution Approach 1:
The patent employs a delay-locked loop (DLL) circuit that dynamically adjusts delay amounts based on feedback to maintain stable phase differences between signals. The DLL continuously monitors and corrects delay variations caused by temperature changes and manufacturing tolerances, ensuring consistent pulse width despite environmental fluctuations.
Solution Approach 2:
The invention implements a feedback mechanism where the phase difference between signals is continuously monitored and used to adjust the delay amounts in the DLL circuit. This closed-loop control ensures that pulse width remains stable by automatically compensating for variations in component characteristics and environmental conditions.
2Adaptability or versatility
If multiple delay circuits are connected in cascade to generate phase differences, then multiple pulses with different phases are generated, but the pulse width becomes sensitive to performance variations
Solution Approach 1:
The DLL circuit dynamically adjusts the delay amounts in each stage of the cascade-connected delay circuits based on feedback signals. This dynamic adjustment compensates for performance variations in individual delay circuits, maintaining consistent phase differences and pulse widths despite manufacturing tolerances and environmental changes.
Solution Approach 2:
A feedback mechanism monitors the actual phase differences between signals emerging from the cascade delay circuits and adjusts the delay amounts accordingly. This ensures that the cumulative delay through multiple stages remains stable, preventing pulse width fluctuations that would otherwise result from component variations.
3Device complexity
If fixed delay circuits are used to generate phase differences, then simple circuit structure is achieved, but pulse width fluctuates with temperature and performance variations
Solution Approach 1:
The patent transforms fixed delay circuits into dynamically adjustable delay elements within a DLL structure. The delay amounts are continuously adapted based on feedback, allowing the circuit to maintain stable pulse width characteristics despite temperature variations and component aging, while adding only moderate complexity through the feedback control mechanism.
Data Source
AI summary
A pulse position modulation circuit includes a delay locked loop circuit configured to include a plurality of delay circuits coupled in a cascade, each of the plurality of delay circuits being configured to delay an input signal by a time width corresponding to a control signal so as to generate an output signal, a plurality of pulse generation circuits, each of which is configured to generate a pulse with a pulse width corresponding to a phase difference between a first signal and a second signal which have different phases from each other at different timings corresponding to states of the first signal and the second signal, each of the first signal and the second signal being the input signal or the output signal of the plurality of delay circuits, and a selection circuit configured to select pulses generated by the plurality of pulse generation circuits.