APSK Modulation with Variable Pulse Timing for Limited Signal Generators
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Solution Overview
Problem
Existing signal generators face hardware limitations that hinder efficient APSK modulation, affecting information throughput, error probability of demodulation, and transmission power.
Innovation Solution
A method and apparatus for APSK signal generation using a signal generator with a transmission line, comprising switches for amplitude, carrier phase, and pulse position control, allowing selection of modulation symbols with varying durations and pulse positions to mitigate hardware limitations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional signal generators are used for APSK modulation, then hardware simplicity is maintained, but information throughput decreases and error probability increases
Solution Approach 1:
The modulation symbol is segmented into multiple components: amplitude, carrier phase, and pulse position. Each component is independently controlled by dedicated switches (amplitude control switch, carrier phase control switch, pulse position control switch), allowing precise manipulation of each parameter to improve throughput and reduce errors
Solution Approach 2:
The signal generator employs dynamic control mechanisms where switches can be selectively activated or deactivated based on the desired modulation symbol. The pulse position varies dynamically within the symbol duration, and the carrier phase can be shifted dynamically, enabling adaptive modulation that improves both throughput and reliability
2Device complexity
If signal generators with hardware limitations are used, then device complexity is reduced, but transmission power increases
Solution Approach 1:
The system uses periodic pulse actions within the symbol duration to achieve modulation. By concentrating energy into periodic pulse events rather than continuous transmission, the system reduces average transmission power while maintaining effectiveness with simpler hardware
Solution Approach 2:
The invention changes key parameters of the signal including pulse position, amplitude, and carrier phase to achieve modulation. By varying these parameters dynamically rather than maintaining constant high power, the system reduces transmission power requirements while working within hardware limitations
3Productivity
If modulation symbols with varying durations are used, then information throughput is improved, but synchronization difficulty increases
Solution Approach 1:
A reference signal or synchronization marker is introduced as an intermediary element within the modulation scheme. This reference allows the receiver to synchronize with varying symbol durations by providing a known timing reference point, thus enabling variable duration symbols without excessive synchronization difficulty
Data Source
AI summary
A method of providing a modulated signal for transmission is disclosed. The method includes selecting a modulation symbol, and operating a signal generator to provide the selected modulation symbol for transmission.Each available modulation symbol has a symbol duration, includes a pulse, and indicates information by a combination of an amplitude of the pulse and a carrier phase of the pulse. A position of the pulse is defined within the symbol duration, and at least two of the available modulation symbols have different symbol durations.The combination may further include the position of the pulse.In some embodiments, the pulse represents an end of the available modulation symbol, and the pulse is preceded by a silent period.A corresponding method of processing a received signal of modulation symbols is also disclosed; as well as corresponding computer program products, apparatuses, and communication devices.