Asynchronous Sigma-Delta Probe Readout for Remote Ultrasound ADC
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Solution Overview
Problem
High voltage technologies in ultrasound systems are not suitable for complex signal processing due to large transistor feature sizes, leading to high area and power consumption, and analog signal propagation is challenging over long distances with potential interference, especially in systems requiring multiple transducers and increased data channels.
Innovation Solution
A signal processing system using asynchronous sigma-delta modulation to transform analog signals into digital time-domain signals, allowing robust propagation and multiplexing of signals with reduced susceptibility to interference, and incorporating a time gain function to adjust dynamic range based on imaging depth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high voltage technologies are used to drive acoustic transducer elements, then the transducer elements can be driven and signals amplified, but the large transistor feature sizes lead to prohibitively high area and power consumption
Solution Approach 1:
The system is divided into two separate integrated circuits: a high voltage ASIC for transducer driving and signal amplification, and a low voltage ASIC for analog-to-digital conversion and digital signal processing. This segmentation allows each circuit to be optimized for its specific voltage requirements, enabling the low voltage ASIC to use smaller transistors with lower area and power consumption while the high voltage ASIC handles only the functions requiring high voltage
Solution Approach 2:
An intermediate signal transmission interface is introduced between the high voltage and low voltage ASICs. The high voltage ASIC outputs amplified analog signals that are transmitted through an interconnecting cable to the low voltage ASIC, which then performs the complex signal processing functions. This intermediary approach allows the separation of high voltage driving functions from low voltage processing functions
2Use of energy by stationary object
If the low voltage integrated circuit is located in a back end processing unit connected via cable, then complex signal processing can be performed with low power consumption, but analog signal propagation becomes difficult due to signal integrity issues, dissipation, and interference
Solution Approach 1:
Analog beamforming is performed in advance at the high voltage ASIC before signal transmission to the back end processing unit. By pre-processing the signals and forming beams analogously, the amount of data that needs to be transmitted is reduced, and the signals are prepared in a form that is more robust to transmission losses and interference
Solution Approach 2:
The system incorporates feedback mechanisms in the analog beamforming process at the high voltage ASIC, allowing real-time adjustment of beam parameters and signal levels before transmission. This feedback enables compensation for anticipated transmission losses and interference, improving signal integrity at the receiving end
3Productivity
If the number of ultrasound transducers is increased in a 2D configuration, then more data channels are acquired, but the amount of data to be propagated increases significantly requiring more parallel cables
Solution Approach 1:
Multiple data channels from the increased number of transducers are merged and processed through the high voltage ASIC before transmission to the back end processing unit. The high voltage ASIC consolidates the signals from multiple channels, performing analog beamforming and signal combination, which reduces the overall complexity of the data transmission infrastructure required to handle signals from a large array of transducers
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 reliable and efficient transfer of ultrasound signals over variable distances with improved dynamic range and reduced power consumption, facilitating the use of high voltage components and allowing for massively parallel read-out of transducers without the need for significant additional hardware.
Implementation Method 1
an asynchronous sigma-delta modulator, wherein the asynchronous sigma-delta modulator is adapted to: receive the analog probe signal; and output a binary bit-stream
Data Source
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AI summary
The invention provides a signal processing system, for transferring analog signals from a probe to a remote processing unit. The system comprises a first ASIC at a probe, which is adapted to receive an analog probe signal. The first ASIC comprises an asynchronous sigma-delta modulator, wherein the asynchronous sigma-delta modulator is adapted to: receive the analog probe signal; and output a binary bit-stream. The system further comprises a second ASIC at the remote processing unit, adapted to receive the binary bit-stream. The asynchronous may further include a time gain function circuit, the first ASIC may further comprise a multiplexer, the second ASIC may further comprise a time-to-digital converter. The time to digital converter may be a pipelined time-to-digital converter.