Linear transducer array and method for both pulse-echo and holographic acoustic imaging

Apparatus for receiving acoustic waves, comprising:

• (a) a linear array of receiving elements disposed in a plane and along a first axis;
• (b) a plurality of buffer amplifiers for individually amplifying the signals detected by the receiving elements, each buffer amplifier both receives power and transmits signals through a single conductor;
• (c) a plurality of cascode amplifiers each driven by a buffer amplifier and each providing a large output signal voltage corresponding to the acoustic waves detected by the receiving elements;
• and
• (d) switch means connected to the cascode amplifiers for selecting a desired cascode amplifier and corresponding receiving element from among the receiving elements in the linear array.

Apparatus for ultrasonically inspecting mechanical components, comprising:

• (a) a transducer array having both transmitting elements and receiving elements;
• (b) a removable mechanical shutter adapted to block a portion of the transmitting elements for holographic imaging;
• (c) means for energizing the array so that a steerable collimated beam of acoustic waves is propagated for pulse-echo imaging and a dispersive beam of acoustic waves is propagated for holograph imaging;
• and
• (d) means for mechanically translating the array with respect to a mechanical component so that the mechanical component can be inspected ultrasonically.

A method of ultrasonically inspecting mechanical components, comprising the steps of:

• (a) energizing sequentially an array of transmitting transducer elements so that a steerable beam of collimated acoustic waves is propagated therefrom;
• (b) detecting the acoustic waves with an array of receiving transducer elements so that a pulse-echo image of the mechanical components can be obtained;
• (c) energizing a restricted portion of an array of the same transmitting transducer elements so that a dispersive beam of acoustic waves is propagated therefrom;
• and
• (d) detecting the acoustic waves with an array of receiving transducer elements so that a holographic image of the mechanical components can be obtained.

An apparatus for receiving acoustic waves and for processing signals corresponding thereto, comprising:

• (a) a linear array of receiving elements disposed in a plane and along a first axis, each element being adapted for converting the acoustic waves incident thereon into corresponding analog output signals;
• (b) means for digitizing the analog output signals from the receiving elements by detecting and quantitizing the envelope of the output signals;
• (c) shift register means constituting a digital delay line with multiple output taps, said shift register means being adapted for delaying the digitized signals by predetermined time intervals;
• and
• (d) a digital to analog converter for converting the delayed, digitized signals from the shift register means into corresponding analog signals.

An apparatus for receiving acoustic waves and for processing signals corresponding thereto, comprising:

• (a) a linear array of receiving elements disposed in a plane and along a first axis, each element being adapted for converting the acoustic waves incident thereon into corresponding analog output signals;
• (b) a plurality of analog signal delaying channels, each channel including a distributed constant analog delay line and an analog multiplexer for selecting the time delay interval achieved by the distributed constant delay line;
• and
• (c) means for connecting the output signals from the receiving elements to the analog delaying channels so that the linear array is scanned in a predetermined manner.