Near-field Measurement System Phase Error Reduction
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Solution Overview
Problem
Conventional near-field measurement systems require two down-converters, making them expensive and prone to errors due to signal degradation when using a trigger signal for phase measurement, which can be mitigated but at the cost of increased measurement time.
Innovation Solution
A near-field measurement system that uses a single frequency converter and digitizes both the radio signal and synchronization signal, generating a timing signal for phase measurement to reduce errors and costs, while maintaining a constant phase relationship among the trigger, local, and clock signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If two down-converters are used in the near-field measurement system, then phase measurement accuracy is improved, but device cost increases
Solution Approach 1:
The patent extracts the phase reference function from the second down-converter and implements it through digital signal processing. The synchronization signal is digitized by a second A/D converter and processed by a timing processing unit to generate timing signals, separating the frequency conversion function from the phase reference function. This eliminates the need for the second down-converter while maintaining phase measurement accuracy.
Solution Approach 2:
The patent replaces the hardware-based phase reference system (second down-converter) with a software/digital processing system. The timing processing unit generates timing signals by processing the digitized synchronization signal, substituting the mechanical/electrical frequency conversion process with digital signal processing operations.
2Device complexity
If a trigger signal is used for phase measurement, then device cost is reduced, but measurement accuracy deteriorates due to signal degradation
Solution Approach 1:
The patent applies preliminary action by digitizing the synchronization signal before it degrades. The second A/D converter captures the synchronization signal in its original form, preserving its characteristics. The timing processing unit then processes this preserved signal to generate accurate timing signals, preventing the degradation that would occur if the signal were transmitted through cables as an analog trigger signal.
Solution Approach 2:
The patent replaces the analog trigger signal transmission system with a digital signal processing system. Instead of transmitting the synchronization signal through cables where it degrades, the system digitizes it and processes it electronically, eliminating the signal degradation problem associated with analog transmission.
3Measurement precision
If multiple measurements and averaging are performed to reduce error, then measurement accuracy is improved, but measurement time increases
Solution Approach 1:
The patent replaces the time-consuming multiple measurements and averaging process with a single-shot accurate measurement system. By digitizing the synchronization signal and using precise timing signal generation, the system achieves high measurement accuracy in a single measurement cycle, eliminating the need for repeated measurements and averaging.
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
This configuration allows for accurate and cost-effective near-field measurements with reduced errors by using a timing signal for phase correction, eliminating the need for multiple frequency converters and maintaining phase consistency across measurements.
Implementation Method 1
a frequency converter that frequency-converts a frequency of the radio signal received by the measurement probe to a desired frequency
Implementation Method 2
a measurement probe that receives the radio signal at a plurality of measurement positions
Implementation Method 3
a first A/D converter that digitizes the radio signal frequency-converted by the frequency converter; and a second A/D converter that digitizes a synchronization signal
Data Source
AI summary
A near-field measurement system includes a measurement probe 11 that receives a radio signal that is transmitted from an antenna under measurement 110 at a plurality of measurement positions included in a predetermined scan range, a frequency converter 13 that frequency-converts a frequency of the radio signal to a desired frequency, a timing processing unit 18 that generates a timing signal for starting measurement of an amplitude and a phase of the radio signal from a trigger signal output from a transmission device 100 in synchronization with transmission of the radio signal, and an amplitude and phase calculation unit 19 that acquires a radio signal frequency-converted by a frequency converter 13 and digitized by an A/D converter 14a on the basis of a timing signal for each measurement position and calculates an amplitude and a phase in a near field of the acquired radio signal.