Transmitter Drive Frequency Modulation for Lower Electromagnetic Emissions
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Solution Overview
Problem
Conventional transmitter devices face challenges in optimizing performance and reducing electromagnetic emissions to comply with emission standards without compromising operating performance, particularly in medical imaging applications like ultrasound probes.
Innovation Solution
The method involves driving the transmitter device with an electrical signal comprising different driving frequencies selected based on the target frequency, allowing for improved performance and reduced electromagnetic emissions without requiring structural modifications or additional devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the transmitting device operates with a predefined frequency to maintain stable operation, then the operating performance is preserved, but the electromagnetic emissions may exceed permitted limits
Solution Approach 1:
The patent applies parameter changes by varying the driving frequency of the electrical signal over time. Instead of using a single predefined frequency, the system dynamically adjusts the frequency parameter to achieve spectral spreading, which reduces peak electromagnetic emissions while maintaining the same time-averaged acoustic power delivery to the transducer elements.
Solution Approach 2:
The patent implements periodic action by using a frequency modulation scheme where the driving frequency varies periodically or pseudo-randomly around the target frequency. This periodic variation in frequency creates a spread spectrum effect that distributes the electromagnetic energy across multiple frequency bins, reducing the peak emissions at any single frequency while maintaining the desired acoustic output.
2Measurement precision
If multiple transducer elements are driven simultaneously to improve imaging performance, then the image quality increases, but the total electromagnetic emissions increase
Solution Approach 1:
The patent applies segmentation by dividing the simultaneous driving of multiple transducer elements into time-multiplexed segments. Different groups of transducer elements are activated at different time intervals with different frequency modulations, which spreads the electromagnetic emissions across both time and frequency domains. This allows maintaining the capability to drive multiple elements while reducing peak emissions through temporal and spectral distribution.
3Power
If the electrical signal power is increased to improve acoustic output, then the operating performance improves, but the electromagnetic emissions exceed compliance limits
Solution Approach 1:
The patent applies dynamics by implementing a dynamic frequency modulation strategy where the driving frequency continuously varies according to a predetermined pattern. This dynamic approach allows the system to maintain high acoustic output power through constructive interference and resonance effects at different frequencies, while the time-varying nature of the signal prevents sustained high-level electromagnetic emissions at any single frequency, thereby complying with emission standards.
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 approach enhances the operating performance of transmitter devices while adhering to electromagnetic emission limits, ensuring compliance with standards and maintaining or improving image quality across various operating modes.
Implementation Method 1
one or more transducers are used to convert electrical energy into ultrasonic waves
Implementation Method 2
each of the transducer elements converts a received echo signal into an electrical signal
Data Source
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AI summary
This disclosure relates to a method for driving a transmitting device, in which the transmitting device operates at a target frequency (f0). The method comprises: driving the transmitting device with an electrical signal comprising different drive frequencies (f1, f2) selected according to the target frequency (f0).