Propagation tuned oscillator for orthopedic parameter measurement
View Patent ↗A measurement system for capturing a transit time, phase, or frequency of energy waves propagating through a propagation medium ( 702 ) is disclosed. The measurement system comprises two different closed-loop feedback paths. The first path includes a transducer driver ( 726 ), a transducer ( 704 ), a propagation structure ( 702 ), a transducer ( 706 ), and a zero-crossing receiver ( 740 ). The series and parallel resonance of the transducer ( 704 ) does not overlap the series and parallel resonance of the transducer ( 706 ). A second path includes a transducer driver ( 1126 ), a transducer ( 1104 ), a propagation medium ( 1102 ), a reflecting surface ( 1106 ), and an edge-detect receiver ( 1140 ). Each positive closed-loop path maintains the emission, propagation, and detection of energy waves in the propagation medium ( 702, 1102 ). In either path, a propagation tuned oscillator maintains positive closed-loop feedback of the system that sustains detection, emission, and propagation of energy waves or pulses in a medium.
1. A propagation tuned oscillator (PTO) to maintain positive closed-loop feedback of energy waves in an energy propagating structure where energy waves propagate through a medium configured to couple to the muscular-skeletal system such that detection of a propagated energy wave initiates an energy wave emission into the medium, where the medium is configured to measure a parameter of the muscular-skeletal system, and where the parameter affects the medium.
2. The PTO of claim 1 where the propagation tuned oscillator tunes a resonant frequency of the energy waves in accordance with physical changes in the energy propagating structure.
3. The PTO of claim 2 where an integer number of energy waves propagates in the medium when positive closed-loop feedback is applied.
4. The PTO of claim 2 where the PTO measures one of transit time, frequency, or phase of a propagated energy wave.
5. The PTO of claim 4 where a parameter to be measured is applied to the medium and where changes in the parameter affect one of transit time, frequency, or phase of a propagated energy wave.
6. The PTO of claim 4 where a positive closed-loop feedback path of the PTO comprises a transducer driver configured to drive at least one transducer for the emission of energy waves into the medium, the energy propagating structure, and a zero-crossing receiver configured to detect the propagated energy wave.
7. The PTO of claim 4 where the positive closed-loop feedback path of the PTO comprises a transducer driver configured to drive at least one transducer for the emission of energy waves into the medium, the energy propagating structure, and a edge-detect receiver configured to detect the propagated energy wave.
8. The PTO of claim 4 where the energy propagating structure comprises:
a first transducer;
the medium where the first transducer is coupled to the medium at a first location; and
a second transducer coupled to a second location of the medium.
9. The PTO of claim 8 where a series and parallel resonance of the first transducer is configured not to overlap a series and parallel resonance of the second transducer.
10. The PTO of claim 4 where the energy propagating structure comprises:
a transducer;
the medium where the transducer is coupled to the medium at a first location; and
a reflecting surface at a second location of the medium.
11. A wireless sensing assembly comprising:
a sensor comprising:
a first transducer;
a medium where the first transducer is coupled to the medium at a first location; and
a second transducer where the second transducer is coupled to a second location of the medium and where a series and parallel resonance of the first transducer does not overlap a series and parallel resonance of the second transducer;
a propagation tuned oscillator operatively coupled to the sensor to maintain positive closed-loop feedback of energy waves in an energy propagating structure where energy waves propagate through a medium such that detection of a propagated energy wave initiates an energy wave emission into the medium and where the wireless sensing assembly comprises one or more load surfaces, an accelerometer, electronic circuitry, a transceiver, and an energy supply, to measure applied forces and transmit measurement data to a secondary system for further processing and display.
12. The wireless assembly of claim 11 where the medium is a waveguide.
13. The wireless assembly of claim 11 where the medium is compressible.
14. A method of measuring a parameter of the muscular-skeletal system comprising the steps of:
applying the parameter of the muscular-skeletal system to a medium;
maintaining positive closed-loop feedback to sustain the emission of energy waves in the medium;
measuring one of transit time, frequency, or phase of propagated energy waves; and
relating the transit time of one or more propagated energy waves to the parameter being measured.
15. The method of claim 14 further including the step of tuning a resonant frequency of energy waves in accordance with physical changes of the medium where a number of energy waves in the medium is an integer number.
16. The method of claim 14 further including the steps of:
detecting wave fronts of propagated energy waves; and
emitting an energy wave into the medium upon detecting a wave front.
17. The method of claim 14 further including the steps of:
detecting zero crossings of propagated energy waves; and
emitting an energy wave into the medium upon detecting a zero-crossing.
18. The method of claim 14 further including a step of propagating energy waves through a compressible waveguide.