Abstract: An acoustic transducer and method of generating acoustic transmit and receive beams is disclosed. The system includes a plurality of transducer elements arranged to form an array, where the elements are electrically connected into groups which operate at the same electrical phase, where the phases of adjacent groups of elements differ by between about 50 and 70 degrees and a beamforming circuit where the transmit and receive signals are operated with appropriate phase shifts to maintain the between about 50 and 70 degrees phase difference between adjacent groups. The resulting transducer generates transmit and receive beams that are nominally inclined less than about 30 degrees from a planar normal axis of the array.

Abstract: An acoustic transducer and method of generating acoustic transmit and receive beams is disclosed. The system includes a plurality of transducer elements arranged to form an array, where the elements are electrically connected into groups which operate at the same electrical phase, where the phases of adjacent groups of elements differ by between about 50 and 70 degrees and a beamforming circuit where the transmit and receive signals are operated with appropriate phase shifts to maintain the between about 50 and 70 degrees phase difference between adjacent groups. The resulting transducer generates transmit and receive beams that are nominally inclined less than about 30 degrees from a planar normal axis of the array.

Abstract: A movable barrier operator having an electrical motor responsive to control signals for moving the barrier, a controller to control the barrier movements, and two command apparatuses for generating command inputs, which command apparatuses are located remotely from each other. The first command apparatus is mounted in a location remote from the controller and easily accessible by the users, and the second command apparatus is located close proximity to the controller to be easily accessible by an installer at the time of service.

Abstract: A movable barrier operator having improved safety and energy efficiency features automatically detects line voltage frequency and uses that information to set a worklight shut-off time. The operator automatically detects the type of door (single panel or segmented) and uses that information to set a maximum speed of door travel. The operator moves the door with a linearly variable speed from start of travel to stop for smooth and quiet performance. The operator provides for full door closure by driving the door into the floor when the DOWN limit is reached and no auto-reverse condition has been detected. The operator provides for user selection of a minimum stop speed for easy starting and stopping of sticky or binding doors.