Distance ranging apparatus and method

A graphical data digitizing device for determining the position of a movable element with respect to first and second reference locations, comprising:

• a microprocessor system including a central processor unit, a memory, and a timing circuit for producing timing pulses which determine the rate at which said microprocessor performs individual instruction operations;
• means controlled by said microprocessor system for generating propagating wave energy;
• said microprocessor system being adapted to generate and store a first count that depends upon the number of instruction cycles it performs during a time interval that is a function of the travel time of said wave energy traveling between said movable element and said first location, and a second count that depends upon the number of instruction cycles it performs during a time interval that is a function of the travel time of said wave energy traveling between said movable element and said second location;
• said first and second counts being indicative of the distance between said movable element and said first and second locations, respectively.

A graphical data digitizing device for determining the position of a movable element with respect to first and second reference locations, comprising:

• a microprocessor system including a central processor unit, a memory, and a timing circuit for producing timing pulses which determine the rate at which said microprocessor performs individual instruction operations;
• means controlled by said microprocessor system for generating acoustic wave energy pulses at said movable element;
• first and second spaced acoustic receivers coupled to said microprocessor system;
• said microprocessor system being adapted to initiate a first count of instruction cycles of said microprocessor system upon generation of a pulse of acoustic wave energy and to terminate said first count when said acoustic wave energy is received in said first receiver, said microprocessor system also being adapted to initiate a second count of instruction cycles of said microprocessor system upon generation of a pulse of acoustic wave energy and to terminate said second count when said acoustic wave energy is received at said second receiver;
• said microprocessor system being adapted to store the terminated first count and the terminated second count;
• said stored counts being indicative of the distance between said movable element and said first and second receivers, respectively.

A method for determining the distance between an object and a reference position, comprising the steps of:

• providing a microprocessor system including a central processor unit, a memory, and a timing circuit for producing timing pulses which determine the rate at which said microprocessor system performs individual instruction operations;
• generating propagating wave energy under control of said microprocessor system;
• detecting the wave energy after it has passed between said object and said reference position;
• and
• generating and storing in said microprocessor system a count that depends upon the number of instruction cycles performed by said microprocessor system during a time interval that is a function of the travel time of said wave energy traveling between said object and said reference position;
• said count being indicative of the distance between said object and said reference position.

A graphical data digitizing method for determining the position of a movable element with respect to first and second reference locations, comprising the steps of:

• providing a microprocessor system including a central processor unit, a memory, and a timing circuit for producing timing pulses which determine the rate at which said microprocessor performs individual instruction operations;
• generating propagating wave energy under control of said microprocessor system;
• and
• generating and storing in said microprocessor system a first count that depends upon the number of instruction cycles performed by said microprocessor system during a time interval that is a function of the travel time of said wave energy traveling between said movable element and said first location, and a second count that depends upon the number of instruction cycles performed by said microprocessor system during a time interval that is a function of the travel time of said wave energy traveling between said movable element and said second location;
• said first and second counts being indicative of the distance between said movable element and said first and second locations, respectively.