US 5,784,336 A · Delay scheme and apparatus for focussing the transmission and reception of a summed ultrasonic beam

Abstract

A beamformer includes an array having a plurality of channels of delay elements which are constructed of charge coupled devices (CCDs). Each channel has a first plurality of delay elements cells which perform beam focussing and a second plurality of delay elements which perform beam steering. In this manner beam steering delays and beam focussing delays may be calculated independently. Typically, the second plurality of delay elements have a resolution which is typically coarser than the resolution of the first plurality of delay element cells which function to focus the beam. A signal may be inserted into any one of the delay elements of the first plurality to provide an appropriate delay. The signal is then output from the last delay element of the first plurality to the second plurality. The signal is delivered from a selected delay element of the second plurality to a charge sum data bus, which combines the signals output from each of the channels. This combined signal may then be output to a common offset delay block, which in turn outputs the array signal having a common delay. A plurality of such arrays may be coherently combined. If the required delay exceeds the maximum delay provided by each channel, the output of each array may be offset by a maximum delay of a preceding array in the plurality of arrays in order to coherently combine all of the arrays. Desirably, a shift register having a single enable bit is dynamically controlled to select the appropriate delay by selecting a CCD delay cell.

Claims41

Dependent claims

A beamformer for forming a beam at a wavelength .lambda. comprising:

an array of antenna elements;
and
a charge transfer delay device associated with each of said antenna elements and providing a desired delay to its respective antenna element, each said antenna element being each associated with a desired delay so that said array of antenna elements collectively produces a desired beam profile, the desired delay being composed of a desired focus delay for focussing said array of antenna elements at a desired focal length and a desired beam steering delay for steering the beam along a desired azimuth, each said charge transfer delay device including,
a first delay device portion formed of a plurality N of first delay cells of a first delay resolution factor r.sub.1,
a second delay device portion formed of a plurality P of second delay cells of a second delay resolution factor r.sub.2 substantially different from said first delay resolution factor r.sub.1, said second delay device portion being connected to said first delay device portion at a delay resolution interface,
an input port for inputting a signal into a selected one of said plurality N of first delay cells, n cells from said delay resolution interface, to produce a total first delay in said first delay device portion of n*(.lambda./r.sub.1), and
an output port for outputting the signal from a selected one of said plurality P of second delay cells, p cells from the delay resolution interface, to produce a total second delay in said second delay portion of p*(.lambda./r.sub.2);
one of said first and second delay device portions providing said desired focus delay and the other of said first and second delay device portions providing said desired beam steering delay to collectively form the desired delay for each antenna element associated with each charge transfer delay device.

5 more elements

A beamformer for forming an ultrasonic beam comprising:

plural antenna sub-arrays, each antenna sub-array including,
plural antenna elements, each said antenna element requiring a desired delay to produce a desired beam profile, said desired delay including a common delay portion common to all antenna elements of said sub-array and an individual delay portion associated with each individual antenna element, said common delay portion and said individual delay portion collectively forming the desired delay for each of said antenna elements,
an individual delay device associated with each of said antenna elements and providing an individual delay portion associated with its respective antenna element, said individual delay portion, when added to the signal associated with each antenna element, forming a time delayed signal and causing the outputs of said individual delay devices associated with each of said antenna elements of a single antenna sub-array to match the desired beam profile when added to a common delay portion,
a signal adder for summing the time delayed signals of each antenna element of said sub-array, and
a sub-array common offset delay device associated with said sub-array and adding a common delay to the output of said signal adder to develop a desired delay for each of said antenna elements of said sub-array;
and
means for summing the outputs of said sub-array common offset delay devices of each of said plural sub-arrays;
the common delay of said sub-array common offset delay device of each said sub-array allowing the desired delay associated with each antenna element to exceed a maximum delay of each individual delay device.

5 more elements

A method for forming a beam at a wavelength .lambda. comprising the steps of:

providing an antenna array having a plurality of antenna elements;
defining a desired beam profile to be emitted from or received by said antenna array, said desired beam profile being developed by associating a desired delay with each of said plural antenna elements, the desired delay including a desired focussing delay and a desired beam steering delay for steering the beam along a desired azimuth;
and
using a charge transfer delay device associated with each of said antenna elements to develop the desired delay assigned to each said antenna element to develop a desired beam profile by,
forming a first delay portion from a plurality N of first delay cells of a first delay resolution factor r.sub.1, and
forming a second delay portion from a plurality P of second delay cells of a second delay resolution factor r.sub.2 substantially different from said first delay resolution factor r.sub.1, said second delay portion being connected to said first delay portion at a delay resolution interface;
inputting a signal into a selected one of said plurality N of first delay cells, n cells from said delay resolution interface to produce a total first delay in said first delay portion of n*(.lambda./r.sub.1);
and
outputting the signal from a selected one of said plurality P of second delay cells, p cells from the delay resolution interface to produce a total second delay in said second delay portion of p*(.lambda./R.sub.2);
one of said steps of forming first and second delay portions providing the desired focussing delay and the other of said steps of forming first and second delay portions providing the desired beam steering delay to collectively form the desired delay for each antenna element associated with each charge transfer device from said total first and second delays.

7 more elements

A method of forming an ultrasonic beam comprising:

a) providing plural antenna sub-arrays, each antenna sub-array including plural antenna elements, each said antenna element requiring a desired delay to produce a desired beam profile, said desired delay including a common delay portion common to all antenna elements of said sub-array and an individual delay portion, said common delay portion and said individual delay portion collectively forming the desired delay for each of said antenna elements,
b) providing an individual delay device associated with each respective antenna element,
c) producing a time delayed signal associated with each antenna element by adding an individual delay produced by the individual delay device produced in said step c) to the signal associated with each antenna element to thereby cause the outputs of said delay devices associated with each of said antenna elements of a single antenna sub-array to match the desired beam profile when added to a common delay portion,
d) summing the time delayed signals of each antenna element of said sub-array to form a time delayed sub-array sum signal, and
e) adding a common delay to the time delayed sub-array sum signal to develop a sub-array output including a desired delay for each of said antenna elements of said sub-array,
f) summing the sub-array outputs;
the common delay of said sub-array added in said step e) allowing the desired delay associated with each antenna element to exceed the maximum delay of each individual delay portion.

4 more elements

Dependencies are inferred from the claim text.

Delay scheme and apparatus for focussing the transmission and reception of a summed ultrasonic beam

Life of this patent

Delay scheme and apparatus for focussing the transmission and reception of a summed ultrasonic beam

Life of this patent

Abstract

Claims41