Digital Wideband Phase Modulator Adaptive Gain Calibration
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Solution Overview
Problem
Wideband phase modulation in communication systems faces challenges in maintaining signal quality due to non-linearity in LC tanks, leading to distortions and violations of spectrum and error vector magnitude limits, especially in advanced cellular standards like LTE, where accurate compensation for large frequency ranges is required.
Innovation Solution
The implementation of a phase modulation system with an adaptive control mechanism, including a phase locked loop, digital controlled oscillator, and digital to time converter, which applies adaptive gain control to mitigate modulation errors and ensure linearity and gain accuracy, by using the output of the digital to time converter as PLL feedback to detect and correct internal modulation errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If wideband phase modulation is used to increase bandwidth, then frequency range is improved, but signal quality deteriorates due to non-linearity in LC tanks
Solution Approach 1:
The patent implements a feedback mechanism where the output of the digital-to-time converter is fed back to the phase-locked loop. This feedback loop detects modulation errors caused by LC tank non-linearity and generates correction signals that are applied to compensate for the distortions, thereby maintaining signal quality across wide frequency ranges.
Solution Approach 2:
The patent dynamically adjusts control parameters of the phase-locked loop and digital-controlled oscillator based on the detected modulation errors. By changing these parameters in real-time, the system compensates for non-linearity effects and maintains accurate phase modulation across the entire wideband range.
2Reliability
If adaptive control mechanism is added to compensate for non-linearity, then signal quality is improved, but device complexity increases
Solution Approach 1:
The phase-locked loop circuit performs multiple functions: it generates the carrier signal, detects modulation errors through feedback, and controls the frequency and phase. By making this single circuit multi-functional, the patent reduces the need for separate dedicated components for each function, thereby limiting the increase in overall system complexity while still providing comprehensive error compensation.
Data Source
AI summary
One embodiment of the present invention relates to a modulation system having a phase locked loop and an adaptive control. The phased lock loop is configured to receive an input signal and an adaptive signal. The input signal is an unmodulated signal, such as a phase component or phase signal. The phase locked loop is also configured to provide an error signal and an output signal. The error signal indicates one or more modulation errors. The output signal is a modulated version of the input signal that has been corrected using the adaptive signal to mitigate the one or more modulation errors.