Asynchronous Sigma-Delta ADC for Spatially Separated Ultrasound Stages
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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 and multiplexing difficulties.
Innovation Solution
A signal processing system using an asynchronous sigma-delta modulator at the ultrasound probe to convert analog signals into digital time-domain signals, which are then propagated robustly to a remote processing unit, allowing for adjustable dynamic range and multiplexing of multiple signals without the need for significant additional hardware.
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 area and power consumption increase prohibitively and processing speed decreases
Solution Approach 1:
The system divides the integrated circuit into two separate units: a high voltage integrated circuit for driving transducer elements and a low voltage integrated circuit for signal processing. This segmentation allows each circuit to be optimized for its specific function, with the low voltage circuit using smaller transistor feature sizes to reduce area and power consumption while the high voltage circuit handles the power-intensive transducer driving function.
2Use of energy by stationary object
If the high voltage integrated circuit is separated from the low voltage integrated circuit, then power consumption and area are reduced, but analog signal propagation becomes difficult with interference and signal dissipation
Solution Approach 1:
The low voltage integrated circuit performs analog-to-digital conversion immediately upon receiving the analog signal from the high voltage circuit, converting it to a digital signal before transmission. This preliminary conversion prevents signal degradation during transmission, as digital signals are more resistant to interference and dissipation over the cable connection between the two circuits.
Solution Approach 2:
The patent introduces a digital signal as an intermediary between the high voltage and low voltage circuits. Instead of transmitting analog signals through the cable connection, the analog signal is converted to digital form, which acts as a robust intermediary that maintains signal integrity over variable distances and reduces the impact of interference and signal dissipation.
3Quantity of substance
If analog beamforming is used to reduce data transport, then data volume is reduced, but maximum dynamic range and spatial resolution are limited
Solution Approach 1:
Instead of performing analog beamforming to reduce data volume, the patent inverts the approach by performing analog-to-digital conversion at the front end, converting analog signals to digital form before transmission. This allows full digital signal processing capabilities to be applied, achieving superior spatial resolution and dynamic range while transmitting digital data that can be efficiently compressed and processed.
4Device complexity
If multiple analog channels are multiplexed on a single line, then cable requirements are reduced, but multiplexing difficulties and signal interference increase
Solution Approach 1:
The system performs analog-to-digital conversion at the front end, converting multiple analog channels to digital form before transmission. This preliminary conversion allows each channel to be transmitted as a separate digital signal that is immune to interference, eliminating the multiplexing problems that would occur with analog signals while still reducing cable requirements through efficient digital data transmission.
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.