Methods of and apparatus for ascertaining the characteristics of motion of inaccessible moving elements

Apparatus for obtaining a signal containing information as the characteristics of at least one oscillatorily moving element situated internally of a living body, comprising, in combination:

• a. means for generating an alternating electrical signal;
• b. means connected to said generating means for transducing the alternating electrical signal, as a transmitting signal, into stress wave energy and for radiating such energy at a transmitting station externally of the body and spaced a distance from the element and in a direction to be incident on the element;
• c. means disposed for receiving, at a receiving station externally of the body, and spaced a distance from the element, at least part of the wave energy reflected from the element, and for transducing such received energy into a received electrical signal;
• d. means connected for processing the received electrical signal to produce an electrical output signal at the difference frequency between the then existing transmitting signal and the received electrical signal;
• e. means connected to said generating means for sweeping the frequency of the transmitting signal cyclically in sufficiently long sweeps, with a predetermined frequency vs. time pattern and sufficiently wide band frequency excursion range during each cycle so related to the distances of the transmitting and receiving stations from the element and the movement of the element that the difference frequency is in the audible range of frequencies containing an audibly discernible frequency pattern identifying variations in displacement of the position of the element and motion of the element;
• and
• f. means connected to said processing means for transducing the audible range of frequencies containing such audibly discernible frequency pattern of the electrical output signal into an audible output signal.

A method of obtaining a signal containing information as to the characteristics of displacement and motion of at least one moving element of a living organism situated internally of a living body, such method comprising the steps of:-

• a. generating an alternating electrical signal, herein called the transmitting electrical signal, and which is of ultrasonic frequency, transducing the transmitting electrical signal into stress wave energy, and transmitting such stress wave energy along a path extending from a transmitting station at the surface of said body to said element,
• b. receiving at a receiving station, also at the surface of said body, at least part of the wave energy reflected from the element along a path therefrom to said receiving station and frequency shifted by Doppler effect and time shifted by transit along said paths, and transducing said received energy into a received electrical signal,
• c. combining said Doppler shift of frequency and said time shift into a single resultant frequency shift by an intermodulating operation between a succession of frequency sweep electrical signals generated for said operation, the transmitting electrical signal, and the received electrical signal, and selectively filtering the intermodulation products to derive an electrical output signal of audible frequency persisting over each of a plurality of successive but time spaced periods in each of which change of position and change of motion of the element is reflected as a combined or resultant frequency change,
• d. and transducing said electrical output signal into an audio output signal.