Digital measuring system

Claim 1

An apparatus for measuring the position of a movable element, said apparatus having a signal source driving an analogue transducer connected to the element and a converter responsive to a periodic output of the transducer for producing a periodic square wave output, the apparatus comprising: a. a clock oscillator for producing a constant frequency pulse rate; b. a phase counter connected to the clock oscillator and having inputs for selectively increasing and decreasing the periodicity of an output square wave form; c. a first phase detector having inputs connected to the converter and the phase counter for providing a binary signal to one of the inputs of the digital counter indicating direction of a phase difference between the inputs; d. a second phase detector having inputs connected to the clock oscillator, the converter and the phase counter for producing an output pulse on each period of the inputs in which a phase difference is detected; e. a third phase detector having inPuts connected to the clock oscillator, the converter and the phase counter for periodically generating a number of pulses proportional to the magnitude of a phase difference between the square wave output and the output square wave form that exceeds a predetermined phase difference magnitude; f. a gating network having inputs connected to the second phase detector and the third phase detector and providing an output to the other of the inputs of the phase counter; and g. a digital accumulator having inputs connected to the first phase detector and the gating network for producing a digital number word therein representing the position of the movable element.

Claim 2

An apparatus for measuring the position of a movable element, said apparatus having a signal source driving an analogue transducer connected to the element and a converter responsive to a periodic output of the transducer for producing a periodic square wave output, the apparatus comprising: a. a clock oscillator for producing a constant frequency pulse rate; b. a phase counter connected to the clock oscillator and having inputs for selectively increasing and decreasing the periodicity of an output square wave form; c. a first phase detector having inputs connected to the converter and the phase counter for providing a binary signal to one of the inputs of the digital counter indicating direction of a phase difference between the inputs; d. a second phase detector having inputs connected to the clock oscillator, the converter and the phase counter for producing an output pulse on each period of the inputs in which a phase difference is detected; e. a third phase detector having inPuts connected to the clock oscillator, the converter and the phase counter for periodically generating a number of pulses proportional to the magnitude of a phase difference between the square wave output and the output square wave form that exceeds a predetermined phase difference magnitude; f. a gating network having inputs connected to the second phase detector and the third phase detector and providing an output to the other of the inputs of the phase counter; and g. a digital accumulator having inputs connected to the first phase detector and the gating network for producing a digital number word therein representing the position of the movable element.

Claim 4

An apparatus for measuring the position of a plurality of movable members by applying an analogue transducer to each member, each transducer having an input coupled to a signal source and an output connected to a respective converter for generating a square wave output per member, the apparatus comprising: a. a clock oscillator for producing a constant frequency pulse rate; b. a digital counter for each movable member coupled to the clock oscillator and including inputs for selectively increasing and decreasing the periodicity of an output square wave form; c. a plurality of sign phase detectors, each having inputs connected to one of the converters and a corresponding digital counter for providing a binary signal to one of the inputs of the digital counter, said binary signal representing the direction of a shift in phase of one input of the sign phase detector with respect to the other input; d. a plurality of fine phase detectors, each responsive to the constant frequency pulse rate and having inputs connected to one of the converters and a corresponding digital counter, and each includes (1) means for producing a binary output indicating a shift in phase between the inputs of the fine phase detector, and (2) means for producing an output pulse in response to the binary output; e. a plurality of coarse phase detectors, each having inputs connected to the clock oscillator, one of the converters and corresponding digital counter and each includes (1) means for producing a first output pulse width in response to a square wave output, (2) means responsive to the output square wave form for producing a smaller second output pulse width having a time relation with the first pulse width as to be wholly contained therein when there is a predetermined minimum phase difference between the inputs, (3) means for comparing the first pulse width and the second pulse width and producing a resultant pulse having a time duration proportional to the time the second pulse width is not contained within the first pulse width, and (4) means responsive to the constant frequency pulse rate and the resultant pulse for generating a number of pulses, said number being proportional to the time duration of the resultant pulse; f. a plurality of gating networks, each connected to a fine phase detector and corresponding coarse phase detector for producing output signals to the other of the inputs of the digital counter; and g. a plurality of digital accumulators, each connected to the clock oscillator, a sign phase detector and a corresponding gating network for producing a digital number therein representing the position of one of the movable members.

Claim 5

An apparatus for measuring the position of a plurality of movable members by applying an analogue transducer to each member, each transducer having an input coupled to a signal source and an output connected to a respective converter for generating a square wave output per member, the apparatus comprising: a. a clock oscillator for producing a constant frequency pulse rate; b. a digital counter for each movable member coupled to the clock oscillator and including inputs for selectively increasing and decreasing the periodicity of an output square wave form; c. a plurality of sign phase detectors, each having inputs connected to one of the converters and a corresponding digital counter for providing a binary signal to one of the inputs of the digital counter, said binary signal representing the direction of a shift in phase of one input of the sign phase detector with respect to the other input; d. a plurality of fine phase detectors, each responsive to the constant frequency pulse rate and having inputs connected to one of the converters and a corresponding digital counter, and each includes (1) means for producing a binary output indicating a shift in phase between the inputs of the fine phase detector, and (2) means for producing an output pulse in response to the binary output; e. a plurality of coarse phase detectors, each having inputs connected to the clock oscillator, one of the converters and corresponding digital counter and each includes (1) means for producing a first output pulse width in response to a square wave output, (2) means responsive to the output square wave form for producing a smaller second output pulse width having a time relation with the first pulse width as to be wholly contained therein when there is a predetermined minimum phase difference between the inputs, (3) means for comparing the first pulse width and the second pulse width and producing a resultant pulse having a time duration proportional to the time the second pulse width is not contained within the first pulse width, and (4) means responsive to the constant frequency pulse rate and the resultant pulse for generating a number of pulses, said number being proportional to the time duration of the resultant pulse; f. a plurality of gating networks, each connected to a fine phase detector and corresponding coarse phase detector for producing output signals to the other of the inputs of the digital counter; and g. a plurality of digital accumulators, each connected to the clock oscillator, a sign phase detector and a corresponding gating network for producing a digital number therein representing the position of one of the movable members.