Digital ultrasound beam former with flexible channel and frequency range reconfiguration
AssigneeSURF Technology AS
InventorsBjøm A. J. Angelsen, Tonni F. Johansen
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Abstract
A digital ultrasound beam former for ultrasound imaging, that can be configured by a control processor to process the signals from ultrasound transducer arrays with variable number of elements at variable sampling frequencies, where the lowest sampling frequency allows for the highest number of array elements. The maximal number of array elements is reduced in the inverse proportion to the sampling frequency. The beam former can be operated both in a RF-sampling mode and a quadrature mode. Parallel coupling of transmit/receive circuits for each element allow adaption of the receive Noise Figure and transmit drive capabilities to variations in the electrical impedance of the array elements.
Claims30
A processor configurable digital ultrasound beam-former for steering at least one of the direction and the focus of an ultrasound beam from a plurality ultrasound transducer arrays of different types with variable number of array elements and frequencies, wherein signals from array elements of the transducer arrays or sub-aperture groups of the array elements represent analog channels, and wherein said beam-former comprises:
- a set of analog transmitters and receivers, each transmitter comprising a transmitter amplifier and each receiver comprising a receiver amplifier having a receiver output;
- an array coupling device that couples the analog channels to the front connections of one or more of the transmitters and receivers;
- N analog to digital converters (ADCs) operating at a conversion rate fs, N being a whole number, and wherein an ADC input of each ADC is coupled to a respective one of the receiver outputs of the receiver amplifiers via an ADC connector, wherein
- said ADC connector is one of a direct connection between the receiver outputs and the ADC inputs, and a set of N multiplexers (MUXes), wherein inputs to the MUXes are the receiver outputs and outputs of the MUXes connect to the ADC inputs;
- a programmable digital beam forming unit to which ADC outputs of said ADCs are coupled as inputs, said digital beam forming unit being configurable to sort the outputs of said ADCs into digital samples of received signals from said analog channels, configured to provide phase, delay, and amplitude modifications of said sorted signals to produce modified signals, and configured to combine the modified signals into one or more beam signals;
- and
- a control processor configured to selectably configure a functional operation of the beam former through interaction with at least said array coupling device and said beam forming unit, and configured to couple a selectable number of ADCs to sample signals from each analog channel, wherein said beam forming unit sorts the ADC outputs into samples of signals from individual array elements or sub-aperture groups of elements, and to perform beam forming of the analog channels into one or more beam signals.
A processor configurable digital ultrasound beam former for steering at least one of the direction and the focus of an ultrasound beam from a plurality of ultrasound transducer arrays of different types with variable number of array elements and frequencies, wherein each of the ultrasound transducer arrays is individually connectable to the beam former, said beam former comprising:
- K sets of analog transmit/receive circuits, each set containing a transmit amplifier and a receiver amplifier, K being a whole number,
- an array coupling device for coupling signals between array elements or groups of the array elements of an ultrasound transducer array of the plurality of ultrasound transducer arrays to inputs of groups of said transmit/receive circuits,
- N analog multiplexers that selectably connect outputs or sums of outputs of said receiver amplifiers to a single output, N being a whole number less than or equal to K,
- N analog to digital converters (ADCs) operating at a conversion rate fs, wherein the input of each ADC is connected to an output of said N analog multiplexers in a one-to-one connection,
- at least one field programmable digital beam forming circuit to which the outputs of said ADCs are coupled as inputs, said at least one digital beam forming circuit being configured to sort the outputs of said ADCs into digital samples of received signals from the array elements or groups of array elements, introducing delay and amplitude modifications to the sorted signals and combining the modified, sorted signals into one or more beam signals, and
- a functional control processor at least enabled to selectably configure a functional operation of the beam former through interaction with said array coupling means, said multiplexers, and said at least one beam forming circuit, so that the ADC conversion and beam forming takes form as one of:
- a) for each ADC, L of the received signals from the array elements or groups of array elements are in a recurring sequence connected to said each ADC and converted sequentially by said each ADC so that each of said signals are sampled and converted with a sample rate fs/L, said at least one beam forming circuit being configurable by said control processor to separate the outputs of said ADCs into signal samples from each individual one of the array elements for beam forming to operate the ultrasound transducer array with L*N elements where the signal from the each individual one of said array elements is sampled at a frequency fs/L, wherein L is the number of array elements or groups of elements connected to each ADC in the recurring sequence, and
- b) the number of N ADCs are subdivided into groups with M ADCs in each group, where each of said groups of M ADCs converts a received signal from said array elements or groups of said array elements, with a delay shift between the M ADCs in each group of 1/Mfs, and the at least one digital beam forming circuit being configured to use the outputs of said groups of M ADCs to form samples of said signals with sampling rate Mfs, said control processor controlling said at least one beam forming circuit to separate the outputs of said ADCs into signal samples from each individual one of the array elements for beam forming to operate the ultrasound transducer array with N/M elements where the signal from each of the each individual one of said array elements is sampled at a frequency up to M*fs,
- wherein both forms of the ADC conversion and beam forming are configured to perform electronic direction steering of the beam.
Dependencies are inferred from the claim text.