An ultrasound transducer having an annular acoustic aperture is utilized in combination with an echo-ultrasound imaging system having an FM detector. The off-axis transfer function characteristics of the annular transducer substantially improve the lateral resolution of the imaging system as compared with prior art systems which utilized round or rectangular transducer apertures.

Circuitry for reducing side to side jitter in an ultrasound imaging system using a transducer which is mechanically scanned back and forth to cover the area to be imaged. The circuitry includes a filter circuit for providing a correction signal to be added to the transducer position signal. The filter circuit provides a phase lead proportional to the rate of change of the transducer movement. This signal is scaled by a factor which varies linearly as the depth being imaged changes. The correction signal compensates for delays through the transducer positioning and driver circuitry and for depth dependant delays resulting from the movement of the transducer during the scanning operation.

An oscillatory driving mechanism for use with a scanning transducer includes a configured magnet structure having an associated torque coil cooperating therewith. The torque coil is mounted on a pivoting armature which, in turn, carries the scanning transducer through the predetermined arcuate path. A split pole piece magnetic structure is also positioned adjacent the armature. The armature carries a permanent magnet into an adjustable position relative to the split pole piece members. Hall plate sensors are positioned with respect to the pole piece members to detect the position of the armature at any instant.

The apparatus and method for moving a sensor over a workpiece includes a sensor, and an actuating member. The sensor, such as a non-destructive test sensor, is carried by the actuating member, and the actuating member is at least partially disposed within a housing. The actuating member is adapted for automated movement in one direction, and the housing may be configured to be grasped by an operator and manually moved in another direction. As such, the sensor may automatically move in one direction with respect to the workpiece without manual intervention, and manually move in another direction, such that the sensor is moved by the combination of automated and manual movement. In addition, the actuating member may have at least two substantially parallel arms extending from near the sensor, which permits the sensor to slide along the workpiece while maintaining a substantially normal relationship to a surface of the workpiece.

An ultrasonic scanning pulse-generating apparatus includes a rotary encoder for outputting a pulse every time a motor, driving an ultrasonic transducer, rotates through a predetermined angle, and a pulse cycle-measuring circuit for measuring the one-cycle period of pulses output from the rotary encoder. An address pulse output circuit is provided for outputting a pulse during each of the periods defined by dividing the one-cycle period by a predetermined number m. The address pulse output circuit is connected to a scanning pulse-generator including an address-forming circuit for constructing address data from the address pulse obtained by the address pulse output circuit, and a memory storing scanning pulse data and addressed by the address data of the address-forming circuit, to output a scanning pulse.