Distortion Compensation Circuit Tunable Phase Path
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing distortion compensation circuits in directly modulated laser systems, such as those used in CATV systems, fail to effectively address frequency-dependent distortion and changes in system parameters, leading to residual composite second-order (CSO) and composite triple beat (CTB) distortions.
Innovation Solution
A distortion compensation circuit with a tunable phase path that includes a frequency-dependent distortion path and a tunable filter, along with a controllable phase inverter, to generate compensating distortion products that can adjust phase and magnitude in response to system parameters, thereby addressing both frequency-dependent and frequency-independent distortions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed phase path is used in distortion compensation circuits, then the circuit structure is simple, but it cannot compensate for frequency-dependent distortion and changes in system parameters
Solution Approach 1:
The patent applies the Dynamics principle by making the phase path adjustable rather than fixed. A tunable filter is introduced that can dynamically adjust the phase of distortion products based on frequency-dependent characteristics. This allows the compensation circuit to adapt to varying system parameters and frequency conditions, resolving the contradiction between adaptability and complexity by adding only the necessary dynamic element (tunable filter) rather than completely redesigning the circuit.
Solution Approach 2:
The patent applies the Parameter changes principle by introducing a tunable filter that can change the phase parameter of distortion products. The filter adjusts the phase shift based on the frequency of the distortion products, enabling the circuit to compensate for frequency-dependent distortion. This parameter adjustment capability allows the system to adapt to different operating conditions without requiring complete circuit reconfiguration.
2Object-affected harmful factors
If distortion compensation is not applied, then the system is simple, but CSO and CTB distortions significantly degrade signal quality
Solution Approach 1:
The patent applies the Blessing in disguise principle by taking the harmful distortion products generated by non-linear elements and converting them into beneficial compensating signals. The distortion generator intentionally creates distortion products that are then phase-adjusted and combined with the main signal to cancel out the harmful distortions. This transforms the harmful effect of non-linearity into a useful compensation mechanism, reducing CSO and CTB distortions while maintaining system simplicity.
Solution Approach 2:
The patent applies the Preliminary anti-action principle by generating distortion products in advance and adjusting their phase before they are combined with the main signal. The tunable filter pre-adjusts the phase of distortion products to create destructive interference with the harmful distortions. This preliminary adjustment ensures that when the distortion products are combined with the main signal, they automatically cancel out the harmful effects without requiring real-time complex processing.
3Reliability
If frequency-dependent distortion is not compensated, then the circuit remains simple, but residual distortions remain under varying system parameters
Solution Approach 1:
The patent applies the Dynamics principle by introducing a tunable filter that can dynamically adjust its characteristics based on the frequency of distortion products. This allows the circuit to maintain effective compensation across varying system parameters and frequency conditions. The filter's ability to change its phase response dynamically ensures reliable distortion compensation without requiring multiple fixed circuits for different conditions.
Solution Approach 2:
The patent applies the Universality principle by designing a single tunable filter that can handle multiple frequency-dependent distortion scenarios. Rather than requiring separate compensation circuits for different distortion types or frequency ranges, the tunable filter provides a universal solution that can adapt to various distortion conditions through parameter adjustment. This multi-functional approach improves reliability while avoiding the complexity of multiple specialized circuits.
Data Source
AI summary
A distortion compensation circuit compensates for distortion generated by one or more non-linear elements such as a laser device and/or an optical fiber and may include a primary signal path for carrying an input signal and a secondary signal paths for generating distortion. The distortion compensation circuit may also include a controllable phase inverters and a tunable filter. For example, the secondary signal path may include a distortion generator to produce distortion products from the input signal and a signal controlled phase inverter that inverts the phase of the distortion products and a tunable filter that adjusts the phase of the frequency dependent distortion. The phase inversion and tunable filter may be controlled in response to control signals generated based on one or more parameters such as, for example, laser power, input RF channel loading, temperature, and fiber length.