High-Frequency Phase Estimation Using Divider-Mixer DC Sampling
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Solution Overview
Problem
Existing solutions fail to accurately estimate the phase difference between high-frequency signals, especially in high-frequency applications like mmWave phased arrays, where PLLs are complex and existing methods are difficult or impossible to implement, and require shifting phases or changing locked clocks.
Innovation Solution
A system using 1:N frequency dividers, mixers, low-pass filters, and analog-to-digital converters to estimate phase differences by collecting and processing direct current values from the multiplication of divider outputs, employing clustering algorithms like k-means to determine centroids and calculate phase differences without shifting phases or changing locked clocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If frequency dividers are used to estimate phase difference between high-frequency signals, then phase estimation becomes feasible, but the output phase changes randomly when the divider is disabled and re-enabled, making accurate phase estimation difficult
Solution Approach 1:
The patent applies preliminary action by pre-establishing a relationship between the divided clock signals and the original clock signals before phase estimation is performed. The system captures and stores the phase relationship information when the dividers are initially enabled, so that subsequent phase estimations can reference this pre-established relationship rather than dealing with random phase changes upon re-enabling.
Solution Approach 2:
The patent implements feedback by using the captured DC values from the mixer output to iteratively refine the phase difference estimation. The system repeatedly changes the phase of one divider output, collects corresponding DC values, and uses this feedback information to converge on an accurate phase difference measurement, compensating for the inherent randomness in divider phase behavior.
2Measurement precision
If existing phase estimation methods are used for high-frequency signals, then phase synchronization can be achieved, but the system requires shifting phases or changing locked clocks, increasing system complexity
Solution Approach 1:
The patent introduces an intermediary approach by using frequency dividers followed by a mixer and low-pass filter to translate high-frequency phase relationship information into a measurable DC voltage. This intermediary measurement system allows phase estimation without directly manipulating the high-frequency clocks or their phases, thereby reducing the complexity of the PLL and clock control systems while maintaining synchronization accuracy.
Solution Approach 2:
The patent replaces the mechanical/manual approach of adjusting clock phases and re-locking PLLs with an automated electronic measurement system. The system uses digital control to change divider phases and automatically processes the mixer output through ADC and algorithms to determine phase difference, eliminating the need for manual phase shifting and clock re-locking operations.
3Speed
If high-frequency direct measurement is performed, then real-time phase information is obtained, but the measurement system becomes difficult or impossible to implement in applications like mmWave phased arrays
Solution Approach 1:
The patent applies parameter changes by transforming the measurement from the high-frequency domain to the DC domain. The system uses frequency dividers to reduce the frequency of the clock signals, then uses a mixer and low-pass filter to extract phase information as a DC voltage level. This parameter transformation allows real-time phase measurement to be implemented using standard low-frequency components, making the system feasible for applications like mmWave phased arrays where direct high-frequency measurement would be impractical.
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
Enables accurate phase estimation for high-frequency signals without the need for phase shifting or clock changes, using low-frequency commercial components and requiring a small number of measurements, suitable for dual-DAC applications and mmWave phased arrays.
Implementation Method 1
a mixer, two inputs of the mixer coupled to receive the divided clock signals
Implementation Method 2
a low-pass filter, an input of the low-pass filter coupled to an output of the mixer
Data Source
AI summary
A first 1:N frequency divider has an input configured to be coupled to one of two signals and a second 1:N frequency divider has an input configured to be coupled to another of the two signals. A mixer includes two inputs, where each input is coupled to an output of one of the first and second 1:N frequency dividers. A low-pass filter has an input coupled to an output of the mixer and an analog-to-digital converter (ADC) has an input coupled to an output of the low-pass filter. A data collection and analysis block repeatedly changes a phase of an output of the first 1:N divider, collects a set of digitized data generated by the ADC, and estimates the phase difference between the two signals based on the set of digitized data.