Abstract: An acoustical imaging system for producing high resolution medical images provides a method and apparatus for obtaining accurate velocity characterizations of samples within the human body, and for obtaining high resolution images of the samples by utilizing the velocity characterizations of the samples within the human body. The acoustical imaging system also provides a method and apparatus for efficient use of switching channels whereby for a transducer array having a plurality of transducer elements, a set of receiver channels which number less than the number of transducer elements in the array are assigned to a selected portion of the plurality of transducers in the array, wherein for any predetermined set of transducers symmetrically located about a selected transducer, the predetermined set equal in number to the number of receiver channels in the system, each receiver channel in the set of receiver channels is only assigned to one transducer in said predetermined sampling set.

Abstract: Reduced indicia keyboards for, and high security locks utilizing, key entry of a selectable lock code using a number of keys for the entry of each code element, which number of keys is less than the number of possible variations of that code element. Associated with each key is a code element display, viewable only by one operating the lock, to identify which particular value or variation of the code element is associated with that key at any particular time. By varying the association of the keys and the variations in the code elements, the sequence of key depressions and other observations with respect to the operation of the system without knowledge of the specific indicia associated therewith makes such observations useless in later attempting to operate the lock.

Abstract: An acoustical imaging system for producing high resolution medical images provides a method and apparatus for obtaining accurate velocity characterizations of samples within the human body, and for obtaining high resolution images of the samples by utilizing the velocity characterizations of the samples within the human body. The acoustical imaging system also provides a method and apparatus for efficient use of switching channels whereby for a transducer array having a plurality of transducer elements, a set of receiver channels which number less than the number of transducer elements in the array are assigned to a selected portion of the plurality of transducers in the array, wherein for any predetermined set of transducers symmetrically located about a selected transducer, the predetermined set equal in number to the number of receiver channels in the system, each receiver channel in the set of receiver channels is only assigned to one transducer in said predetermined sampling set.

Abstract: A power controller for electric locks which draw large startup current surges which controls and manages the energy of a pair of storage batteries to reliably operate such electric locks and provide steady-state power to auxiliary system components both with AC power present and in the absence thereof, so long as the stored charge in the batteries is able, to thereafter maintain a steady source of power to the system as long as possible, and to be self-starting upon the return of AC power, all without ever placing the electric locks in a partially unlocked or "hung" state. The two storage batteries are normally maintained charged through an AC power source, and both cooperate to provide the surge power. On loss of AC power, both still provide surge power so long as one can maintain the steady state power, and thereafter the other battery alone provides surge power so long as possible.