An ultrasonic holography system comprising: an ultrasonic transducer array including a plurality of transmitter elements configured to emit a plurality of ultrasonic waveforms toward a physical item, and a plurality of receiver elements configured to receive a plurality of return ultrasonic waveforms reflected from the physical item; and a processor system coupled to said ultrasonic transducer array, said processor system configured to: define an analog tone burst waveform; rectangular step sample the analog tone burst waveform to select a multi-level square wave excitation pulse; generate a plurality of outgoing multi-level square wave transmitter driving signals such that at least one of said signals is a rectangular-sampled approximation of a corresponding fully-analog driving signal including a plurality of steps having amplitudes that correspond to amplitudes of counterpart peaks in the corresponding fully-analog driving signal wherein the plurality of steps are selected from a finite set of discrete voltage levels and wherein the at least one signal includes a plurality of steps having widths that correspond to widths between counterpart inflection points in the corresponding fully-analog driving signal and wherein transitions between steps in the at least one signal correspond in phase to counterpart inflection points in the corresponding fully-analog driving signal configured to cause said ultrasonic transducer array to emit said plurality of ultrasonic waveforms, wherein at least two of said plurality of ultrasonic waveforms are differentiated from each other through variation of at least one of amplitude, frequency, phase, time shift, and a modulation of any one thereof; receive a plurality of incoming analog waveform signals, generated by said ultrasonic transducer array, said incoming analog waveform signals representative of at least a portion of said plurality of return ultrasonic waveforms; and process the plurality of incoming analog waveform signals to evaluate the internal structure of the physical item. an ultrasonic transducer array including a plurality of transmitter elements configured to emit a plurality of ultrasonic waveforms toward a physical item, and a plurality of receiver elements configured to receive a plurality of return ultrasonic waveforms reflected from the physical item; and a processor system coupled to said ultrasonic transducer array, said processor system configured to: define an analog tone burst waveform; rectangular step sample the analog tone burst waveform to select a multi-level square wave excitation pulse; generate a plurality of outgoing multi-level square wave transmitter driving signals such that at least one of said signals is a rectangular-sampled approximation of a corresponding fully-analog driving signal including a plurality of steps having amplitudes that correspond to amplitudes of counterpart peaks in the corresponding fully-analog driving signal wherein the plurality of steps are selected from a finite set of discrete voltage levels and wherein the at least one signal includes a plurality of steps having widths that correspond to widths between counterpart inflection points in the corresponding fully-analog driving signal and wherein transitions between steps in the at least one signal correspond in phase to counterpart inflection points in the corresponding fully-analog driving signal configured to cause said ultrasonic transducer array to emit said plurality of ultrasonic waveforms, wherein at least two of said plurality of ultrasonic waveforms are differentiated from each other through variation of at least one of amplitude, frequency, phase, time shift, and a modulation of any one thereof; receive a plurality of incoming analog waveform signals, generated by said ultrasonic transducer array, said incoming analog waveform signals representative of at least a portion of said plurality of return ultrasonic waveforms; and process the plurality of incoming analog waveform signals to evaluate the internal structure of the physical item. define an analog tone burst waveform; rectangular step sample the analog tone burst waveform to select a multi-level square wave excitation pulse; generate a plurality of outgoing multi-level square wave transmitter driving signals such that at least one of said signals is a rectangular-sampled approximation of a corresponding fully-analog driving signal including a plurality of steps having amplitudes that correspond to amplitudes of counterpart peaks in the corresponding fully-analog driving signal wherein the plurality of steps are selected from a finite set of discrete voltage levels and wherein the at least one signal includes a plurality of steps having widths that correspond to widths between counterpart inflection points in the corresponding fully-analog driving signal and wherein transitions between steps in the at least one signal correspond in phase to counterpart inflection points in the corresponding fully-analog driving signal configured to cause said ultrasonic transducer array to emit said plurality of ultrasonic waveforms, wherein at least two of said plurality of ultrasonic waveforms are differentiated from each other through variation of at least one of amplitude, frequency, phase, time shift, and a modulation of any one thereof; receive a plurality of incoming analog waveform signals, generated by said ultrasonic transducer array, said incoming analog waveform signals representative of at least a portion of said plurality of return ultrasonic waveforms; and process the plurality of incoming analog waveform signals to evaluate the internal structure of the physical item.