Analog Beamformer Phase-Shifted Delay Paths for Down-Mixing Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Analog beamformers in ultrasound imaging apparatuses suffer from unwanted frequency components in their output signals due to interference between input and clock signals, leading to decreased signal-to-noise ratio and signal distortion.
Innovation Solution
The proposed analog beamformer generates a second input signal with a phase difference corresponding to a first phase with respect to the input signal, which is then processed through delay circuits to reduce unwanted signal components, specifically down-mixing components, in the output signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If an analog beamformer uses only an input signal and a clock signal, then the device complexity is low, but unwanted frequency components appear in the output signal due to interference between the input and clock signals
Solution Approach 1:
The input signal is divided into two separate input signals with different phases (first phase and second phase). This segmentation allows the beamformer to process the original signal and a phase-shifted version simultaneously, enabling cancellation of unwanted frequency components through destructive interference while maintaining simple device architecture
Solution Approach 2:
A phase-shifted version of the input signal is introduced as an intermediary signal. This intermediate signal with a different phase relationship acts as a mediator that, when combined with the original input signal and clock signal, enables cancellation of unwanted frequency components without adding complex filtering stages
2Reliability
If the beamformer processes signals with interference between input and clock signals, then the basic beamforming function is achieved, but the signal-to-noise ratio decreases and signal quality degrades
Solution Approach 1:
The interference between the input signal and clock signal, which originally caused unwanted frequency components, is converted into a beneficial effect. By introducing a phase-shifted input signal and appropriately timing the delay circuits, the interference patterns are manipulated to produce destructive interference at unwanted frequencies and constructive interference at the desired signal frequency, thereby improving signal-to-noise ratio while maintaining beamforming functionality
3Speed
If delay circuits are used to adjust timing of analog signals, then beamforming is achieved, but down-mixing components appear in the output signal
Solution Approach 1:
The signal processing path is segmented into multiple channels, each with its own delay circuit. The first input signal path includes a first delay circuit while the second input signal path includes a second delay circuit. This segmentation allows independent timing adjustment of each path, enabling cancellation of down-mixing components when the delayed signals are combined
Solution Approach 2:
The phase parameter of the input signal is changed by introducing a phase-shifted version as the second input signal. By adjusting the phase relationship between the two input signals and coordinating the delay times in the respective delay circuits, the frequency components resulting from down-mixing are suppressed while preserving the desired beamformed signal
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
An analog beamformer includes: an input circuit configured to receive an input signal to generate a first input signal having the same phase as the input signal and a second input signal having a phase difference corresponding to a first phase with respect to the input signal; a first delay circuit configured to delay the first input signal to output a first delayed signal; a second delay circuit configured to delay the second input signal to output a second delayed signal; and an output circuit configured to output an output signal by summing the first delayed signal and the second delayed signal, wherein a first write signal has the phase difference corresponding to the first phase with respect to a second write signal, and a first read signal has the phase difference corresponding to the first phase with respect to a second read signal.