Optical PWM Transmission Circuit for Distortion-Free RF Signals
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional transmission devices face challenges in generating pulse width modulation (PWM) signals for RF transmission due to insufficient operation speed of comparators, leading to signal distortion.
Innovation Solution
The transmission device incorporates an optical PWM modulator and a photo detector to generate and convert optical PWM signals based on amplitude and phase information, using a laser light source driven by an oscillation signal and controlled by a bias controller, ensuring high operation speed and minimizing signal distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a conventional comparator is used to generate PWM signals, then the device complexity is reduced, but the operation speed is insufficient leading to signal distortion
Solution Approach 1:
The patent replaces the conventional electrical comparator with an optical system consisting of a laser light source, optical modulator, and photodetector. This substitution enables operation at RF frequencies by using optical domain processing, where the laser generates high-frequency oscillation signals and the optical modulator generates PWM signals based on amplitude information, overcoming the speed limitations of electrical comparators
Solution Approach 2:
The patent introduces an optical intermediary system between the amplitude information input and the PWM signal output. The laser light source and optical modulator act as intermediaries that enable high-speed signal processing by converting electrical signals to optical domain for processing, then converting back to electrical PWM signals, thus achieving both high speed and signal accuracy
2Manufacturing precision
If the PWM signal is generated for RF transmission, then the transmission capability is improved, but the pulse width becomes insufficiently narrow due to comparator limitations
Solution Approach 1:
The patent replaces the slow electrical comparator with an optical-based PWM generation system. The laser light source operating at optical frequencies enables the generation of extremely narrow pulses required for RF transmission, as the optical domain operates at much higher frequencies than electrical comparators, thereby achieving both narrow pulse widths and high operation speeds simultaneously
Solution Approach 2:
The patent changes the operating domain from electrical to optical, utilizing the higher frequency characteristics of optical signals. By using a laser light source with oscillation frequency in the optical range and modulating it with amplitude information, the system generates PWM signals with precisely controlled narrow pulse widths suitable for RF transmission, overcoming the pulse width limitations of conventional electrical comparators
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enables the generation of non-distorted PWM signals for RF transmission, improving the efficiency and accuracy of the transmission process by leveraging the high operation speed of the optical components.
Implementation Method 1
a laser light source configured to be driven by the oscillation signal
Implementation Method 2
a photo detector configured to convert an output light of the laser light source into an electric signal
Data Source
AI summary
A transmission device outputs a modulated signal based on amplitude information and phase information respectively indicating an amplitude and a phase of a transmission symbol. The transmission device includes: an oscillation signal generation circuit configured to generate an oscillation signal based on the phase information; a laser light source configured to be driven by the oscillation signal; a bias controller configured to control a bias current of the laser light source based on the amplitude information; a photo detector configured to convert an output light of the laser light source into an electric signal; and a bandpass filter configured to filter an output signal of the photo detector so as to output the modulated signal.