Method and apparatus for forming multiple beams
First Claim
1. A method for forming a plurality of beams from a reflected signal received by a transducer array having first and second receiver elements, each of said first and second receiver elements receiving the reflected signal at a phase dependent upon the position of the first receiver element relative to the second, the received signal at each of the first and second receiver elements being sampled and converted to a digital signal by first and second associated analog-to-digital converters at a sampling rate defining a time interval during which a first value representing the amplitude of the received signal at the first receiver element and a second value representing the amplitude of the received signal at the second receiver are available during said time interval, comprising the steps of:
- (a) applying a first weighting factor to the first value during a first portion of the time interval to generate a first resultant for a first beam for the first receiver element;
(b) applying a second weighting factor to the first value during a second portion of the time interval to generate a second resultant for a second beam for the first receiver element;
(c) applying a third weighting factor to the second value during a third portion of the time interval to generate a third resultant for a first beam for the second receiver element;
(d) applying a fourth weighing factor to the second value during a fourth portion of the time interval to generate a fourth resultant for a second beam for the second receiver element;
(e) combining the first and third resultants to generate the first beam; and
(f) combining the second and fourth resultants to generate the second beam.
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Accused Products
Abstract
An apparatus and associated method are disclosed which form a multiple beam forming network using time division multiplexing. Instead of having several parallel sets of beam forming network hardware running at a given sampling clock rate, a simpler, single piece of hardware is run at a faster rate equal to the given sampling clock rate times the number of beams to be formed. Each sample received from each element is time division multiplexed into a bit stream, one for each beam. These time division multiplex element samples are weighted to apply the desired phase shift/time delay per element. Each weighted resultant is delayed in a cascade delay pipeline and then combined with the cascade combiner to form a beam at a given time division instant. This process is repeated for the next set of time division multiplexed samples and weights from each element of the array at a given time to form the next beam. The process is repeated for all beams until the sampling time interval ends.
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Citations
26 Claims
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1. A method for forming a plurality of beams from a reflected signal received by a transducer array having first and second receiver elements, each of said first and second receiver elements receiving the reflected signal at a phase dependent upon the position of the first receiver element relative to the second, the received signal at each of the first and second receiver elements being sampled and converted to a digital signal by first and second associated analog-to-digital converters at a sampling rate defining a time interval during which a first value representing the amplitude of the received signal at the first receiver element and a second value representing the amplitude of the received signal at the second receiver are available during said time interval, comprising the steps of:
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(a) applying a first weighting factor to the first value during a first portion of the time interval to generate a first resultant for a first beam for the first receiver element; (b) applying a second weighting factor to the first value during a second portion of the time interval to generate a second resultant for a second beam for the first receiver element; (c) applying a third weighting factor to the second value during a third portion of the time interval to generate a third resultant for a first beam for the second receiver element; (d) applying a fourth weighing factor to the second value during a fourth portion of the time interval to generate a fourth resultant for a second beam for the second receiver element; (e) combining the first and third resultants to generate the first beam; and (f) combining the second and fourth resultants to generate the second beam. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A system for forming a plurality of beams from a reflected signal received by a transducer array having first and second receiver elements, each of said first and second receiver elements receiving the reflected signal at a phase dependent upon the position of the first receiver element relative to the second, the received signal at each of the first and second receiver elements being sampled and converted to a digital signal by first and second associated analog-to-digital converters at a sampling rate defining a time interval during which a first value representing the amplitude of the received signal at the first receiver element and a second value representing the amplitude of the received signal at the second receiver is available during the time interval, comprising:
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(a) a time division multiplexer for sequentially applying first and second weighting factors to the first value to generate first and second resultants for forming first and second beams, respectively, said time division multiplexer sequentially applying third and fourth weighting factors to the second value to generate third and fourth resultants for forming the first and second beams, respectively; and (b) a combiner for combining the first and third resultants to form the first beam and the second and fourth resultants to form the second beam. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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Specification