DPLL Compensation for DCO Frequency Distortion in Polar Modulation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Power efficiency issues in transceiver architectures for portable devices due to parasitic coupling and data loss caused by amplitude modulation (AM) distortions in polar modulation schemes, leading to reduced bandwidth and data loss.
Innovation Solution
A compensation filter and unit are used to mitigate phase distortions caused by AM to FM effects independently of digital phase locked loop (DPLL) filter characteristics, generating a correction signal to account for estimated distortions and reduce frequency-induced distortions in the phase modulation signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If polar modulation concept is used to improve power efficiency, then power efficiency is improved, but AM path introduces distortions into PM path resulting in data loss and reduced bandwidth
Solution Approach 1:
The patent implements a feedback mechanism where the AM signal is monitored and its distortions are measured. A correction signal is then generated based on this feedback and applied to the PM path to compensate for the AM-to-FM conversion distortions, thereby reducing data loss while maintaining power efficiency
Solution Approach 2:
The patent introduces an intermediary compensation mechanism that processes the AM signal characteristics and generates corrective adjustments for the PM path. This intermediary system isolates the PM path from direct AM distortions while preserving the power efficiency benefits of polar modulation
2Use of energy by moving object
If polar modulation concept is used to improve power efficiency, then power efficiency is improved, but bandwidth is reduced
Solution Approach 1:
The feedback system measures bandwidth reduction caused by AM distortions and generates correction signals that pre-distort the AM path or compensate in the PM path, thereby recovering lost bandwidth while maintaining the power efficiency advantages of polar modulation
Solution Approach 2:
The patent dynamically adjusts modulation parameters and compensation factors based on operating conditions to optimize the trade-off between power efficiency and bandwidth utilization, allowing the system to adaptively maximize both performance metrics
3Stability of the object's composition
If vector modulator architecture is used, then linearity is improved, but power efficiency deteriorates due to complete linear signal path requirement
Solution Approach 1:
The patent segments the modulation function into separate AM and PM paths, allowing non-linear power amplification in the AM path while maintaining linearity only where necessary in the PM path. This segmentation enables power efficiency improvement without complete linear signal path
Solution Approach 2:
The patent introduces a compensation mechanism as an intermediary that restores linearity at the output by correcting AM-to-FM conversion distortions, allowing the system to use non-linear efficient amplifiers while maintaining effective signal linearity
Data Source
AI summary
One embodiment of the present invention relates to a communication system having a digital to analog converter, a first input, a summation component, a compensation filter, and a compensation unit. The converter is configured to receive a first signal. The first input is configured to receive a phase modulation signal. The compensation filter generates a filtered frequency deviation signal to mitigate frequency distortions, such as those from a digital controlled oscillator. The compensation unit includes one or more inputs and is configured to generate a correction signal according to the filtered frequency deviation signal and the first signal. The correction signal at least partially accounts for estimated distortions of the phase modulation signal from the amplitude modulation path and mitigates frequency induced distortions. The summation component is configured to receive the phase modulation signal and the correction signal and to generate a corrected phase modulation signal as a result.