|
SELECTED ARTICLES
|
|
|
|
|
|
|
|
|
| PATENT APPLICATIONS |
|
|
| |
Apparatus
and Method for
Class AB Ultrasound LNA Connected to a Transducer via
Coaxial Cable |
| The invention
discloses a
wide-linear-range LNA comprising a Class AB CMOS
transconductor and an I-to-V converter connected in series. The
transconductor receives voltage echo signals from a
transducer and
converters them into RF current. Inherently exhibiting low input
impedance, the proposed transconductor circuit provides active
termination of a transducer cable. Moreover, the LNA input impedance
can be operatively modified for matching cable impedance. A traditional
transimpedance amplifier converts the above mentioned RF current
signals into the form
of voltage. |
|
| |
Method and Means for
Transducer Excitation in Medical Ultrasound Imaging |
The invention
provides a novel method of transducer excitation in medical ultrasound
imaging. Basing on a stepped approximation of Gaussian modulated
cosines, the proposed transmit waveform provides bandlimited spectrum
and low level of second order harmonics while retaining the duration of
the transmitting within two carrier cycles. Since the pulser
architecture is suitable for IC implementation, its development will
reduce the manufacturing cost of medical ultrasound systems. At the
same time, the proposed solution makes the benefits of harmonic imaging
available to midrange and entry-level machines.
|
|
|
|
|
|
|
| |
7,889,787: Ultrasound Transmit
Beamformer Integrated Circuit and Method
|
The invention
provides a novel method of transmit beam- forming , which allows
compact analog implementation of complex digital algorithms without
compromising their features. It is aimed to support envelope shaping,
apodization, and phase rotation per channel and per firing. Each of
three embodiments represents a complete transmit channel driven by
pulse-width modulated (PWM) waveforms. stored in a conventional
sequence memory. PWM signals control the transmit pulse envelope
(shape) by changing the duty cycle of the carrier. Beamformation
data are loaded prior to a firing via serial interface. Under direction
of a controller, the circuitry allows high precision (beyond sampling
rate) phase rotation of the carrier. It is also provides transmit
apodization (aperture weighting), which maintains an optimal trade-off
among low sidelobe level and widening of the mainlobe. Implementing
such an IC, the manufacturing cost of a high-end ultrasound system can
be reduced. Equally, the proposed solution makes the benefits of
digital transmit beamformers available to midrange and
entry-level machines since it merely requires a modified programming of
the sequence memory.
|
|
| |
7,513,873:
Low-Noise Ultrasound Method and Beamformer System for Doppler Processing |
| An ultrasonic
low-noise analog beamformer for Doppler acquisition achieves high
sensitivity by translating the frequency of the ultrasound echoes to an
intermediate frequency, which is well above of the 1/f corner. This is
accomplished by beamforming the downconverted RF signals instead of
using their baseband representation. The baseband conversion,
succeeding the beamformation, also incorporates the steps of clutter
filtering and anti-aliasing. The invention is particularly suitable for
low-voltage process technologies that support broadband applications. |
|
| |
6,808,494:
Transmit Circuit for Imaging with
Ultrasound |
| A DAC with
differential
outputs is
connected to two difference amplifiers through current splitters. The
current splitters isolate the compliance voltage of the DAC so that
larger loads may be used with
the difference amplifiers. This allows to improve the circuit's
SNR. The
difference amplifiers provide current signals to a push-pull output
amplifier through their supply nodes. A single scaling resistor
connects between the conventional outputs of two differential
amplifiers to reduce mismatching between the positive and negative
waveform paths. |
|
|
|
| |
6,572,546: Two
Level
Power Supply and Method for Ultrasound
Transmission |
|
A two level
power supply and
method are provided for ultrasound transmission. A clamping
circuit arranged between a high voltage
power source and a low voltage power
source provides direct current restoration for a two level power supply
selector connected with an ultrasound transmit array. A voltage
rail of the transmit array connects
with
the clamp circuit and receives a low voltage for CW Doppler and a high
voltage for B-mode imaging.
|
|
|
| |
|
A
DAC, which
outputs positive
and negative portions of the desired bi-polar waveform as a
representative
unipolar waveform, is
connected
to a switch. The switch selects between current driver paths as a
function
of the positive or negative polarity of the desired bi-polar waveform.
The current drivers feed a push-pull output amplifier to generate the
bi-polar
ultrasound waveform.
|
|
| |
6,432,055:
Medical
Ultrasonic Imaging System with
Three-State
Ultrasonic Pulse and Improved Pulse Generator |
| A
three-state, pulse width modulated,
bipolar waveform is constructed by summing a first component with an
inverted,
time-shifted version of the first component. By properly selecting the
time interval for the time shift of the second component, frequency
filtering
benefits can be obtained. The three-state waveform is generated by a
switched
voltage source that provides a low, constant source impedance for all
three
voltage states. |
|
|
|
|
|
Home
Site
Map
Links
