Digital Polar Transmitter Phase Error Correction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In wireless communication systems, particularly in wideband OFDM applications, digitally controlled oscillators (DCOs) introduce data-dependent jitter, leading to phase error accumulation, which deteriorates the error vector magnitude (EVM) at the output of polar transmitters.
Innovation Solution
A digital polar transmitter is designed with a phase measuring device to detect phase errors based on measured phase information and apply corrections to the output signal, preventing phase error accumulation by using a phase error detecting device that calculates and compensates for clock jitter, thereby improving EVM.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a digitally controlled oscillator (DCO) is used to generate high frequency signals for wideband OFDM applications, then the sampling rate is improved, but phase error accumulation occurs due to data-dependent jitter
Solution Approach 1:
The patent implements a feedback mechanism where the phase of the DCO output signal is continuously measured and compared against expected phase values. The detected phase errors are then fed back to correct subsequent frequency samples, preventing error accumulation. This closed-loop feedback system maintains phase accuracy while allowing the DCO to operate at high sampling rates required for wideband OFDM applications.
Solution Approach 2:
The patent replaces the purely digital frequency sample integration method with a hybrid approach that incorporates phase measurement and detection mechanisms. By measuring actual phase information from the DCO output and comparing it with expected values, the system substitutes theoretical phase calculation with empirical phase detection, thereby eliminating accumulation errors caused by data-dependent jitter.
2Device complexity
If frequency samples are applied to the ADPLL in a two point way using reference frequency, then the system complexity is reduced, but the sampling rate is insufficient for high symbol rate applications
Solution Approach 1:
The patent changes the fundamental parameter of frequency sample generation from reference-frequency-based two-point modulation to DCO-based continuous frequency sampling. By deriving frequency samples directly from the DCO output at the required high sampling rate, the system achieves the necessary sampling speed for high symbol rate applications while maintaining manageable complexity through the phase error correction mechanism.
3Reliability
If phase error correction is applied to frequency samples, then the EVM is improved, but additional processing complexity is introduced
Solution Approach 1:
The phase error correction mechanism operates as a feedback loop where measured phase errors are immediately applied to correct subsequent frequency samples. This feedback approach improves EVM by continuously compensating for phase deviations while keeping processing complexity manageable through the straightforward implementation of phase measurement, error detection, and correction application.
Data Source
AI summary
The present application relates to at least one digitally controlled oscillator and a data modulation device. More particularly, the digital polar transmitter comprises at least one digitally controlled oscillator configured to generate at least one frequency. The digital polar transmitter comprises a data modulation device, wherein the data modulation device comprises at least one data input terminal, at least one output terminal, and at least one frequency input terminal, wherein the output terminal is connected to the digitally controlled oscillator. The digital polar transmitter comprises a phase measuring device configured to measure phase information from the output signal of the data modulation device for every frequency sample. The digital polar transmitter comprises a phase error detecting device configured to detect a phase error at least depending on the measured phase information, wherein the phase error detecting device is configured to apply the detected phase error to the output signal of the data modulation device.