Systems and methods for measuring the frequency of signals generated by high frequency medical devices

• US 10,073,125 B2
• Filed: 12/13/2016
• Issued: 09/11/2018
• Est. Priority Date: 06/29/2012
• Status: Active Grant

• Current Assignee: Covidien LP (Medtronic Plc)
• Original Assignee: Covidien LP (Medtronic Plc)
• Inventors: Moul, Wayne L., Behnke, II, Robert J., Frushour, Scott E. M., Jensen, Jeffrey L.
• Primary Examiner(s): Koval, Melissa
• Assistant Examiner(s): NGUYEN, TRUNG Q
• Application Number:
  US15/377,740
• Publication Number:
  US 20170089962A1
• Time in Patent Office: 637 Days
• Field of Search: 324 7611, 324 7639- 7654, 324 7668, 324 85, 324520, 324633, 324667, 324674, 324681, 324727, 324600
• CPC Class Codes: A61B 18/1206 Generators therefor
• CPC Class Codes: A61B 18/1815 using microwaves
• CPC Class Codes: A61B 2018/00642 with feedback, i.e. closed loop control
• CPC Class Codes: A61B 2018/00773 Sensed parameters
• CPC Class Codes: A61B 2018/00845 Frequency
• CPC Class Codes: A61B 2018/00869 Phase
• CPC Class Codes: A61B 2018/128 generating two or more frequencies
• CPC Class Codes: A61B 2018/1823 Generators therefor
• CPC Class Codes: G01R 23/00 Arrangements for measuring frequencies; Arrangements for analysing frequency spectra
• CPC Class Codes: G01R 23/02 Arrangements for measuring frequency, e.g. pulse repetition rate; Arrangements for measuring period of current or voltage
• CPC Class Codes: G01R 23/145 by heterodyning or by beat-frequency comparison with the harmonic of an oscillator
• CPC Class Codes: G01R 25/00 Arrangements for measuring phase angle between a voltage and a current or between voltages or currents
• CPC Class Codes: G01R 25/02 in circuits having distributed constants

Abstract

A digital measurement system includes an oscillator, a mixer, and a controller coupled to each other. The oscillator provides a reference signal having a second frequency. The mixer generates a down-converted signal based on the output signal and the reference signal. The controller then determines a characteristic of the output signal (e.g., frequency or phase) based on the down-converted signal. An analog measurement system includes a filter having a center frequency, a rectifier, and a controller. The filter filters the output signal and the rectifier rectifies the filtered signal. The controller samples the rectified signal and determines a characteristic of the output signal based on the level of the rectified signal. The reference signal controller may adjust a characteristic of the output signal based on the determined frequency and/or phase of the output signal.

Claims

1. A generator comprising:

a first oscillator configured to generate an output signal having a first frequency;

a second oscillator configured to generate a reference signal having a second frequency;

a first mixer coupled to the first oscillator and the second oscillator and configured to generate a down-converted signal based on the output signal and the reference signal;

a controller configured to determine an actual frequency of the output signal based on the down-converted signal;

an amplifier configured to amplify the output signal and generate an amplified output signal; and

a second mixer configured to generate a second, down-converted signal based on the amplified output signal and the reference signal, wherein the controller is further configured to;

operate at a clock frequency that is lower than the first frequency; and

determine a phase of the amplified output signal based on the second, down-converted signal.

2. The generator according to claim 1, wherein the output signal is a digital signal or an analog signal.

3. The generator according to claim 1, wherein the controller is further configured to control the output signal based on the actual frequency of the output signal.

4. The generator according to claim 1, wherein the second frequency is a fixed frequency or a variable frequency.

5. The generator according to claim 1, wherein the second frequency is set to a frequency such that the difference between the first frequency and the second frequency is less than a clock frequency of the generator.

6. The generator according to claim 1, wherein the second frequency is adjustable and is set to be the same as the first frequency.

7. The generator according to claim 1, wherein the second frequency is adjustable and is set to be different from the first frequency.

8. The generator according to claim 1, further comprising a sensor coupled to an output of the amplifier, the sensor configured to sense the amplified output signal and transmit a sensed, amplified output signal to the second mixer.

9. A generator, comprising:

an oscillator configured to generate an output signal;

a first filter having a first center frequency and configured to filter the output signal to generate a first filtered signal;

a first rectifier configured to rectify the first filtered signal to generate a first rectified signal;

an amplifier configured to amplify the output signal to generate an amplified output signal;

a second filter having a second center frequency and configured to filter the amplified output signal to generate a second filtered signal;

a second rectifier configured to rectify the second filtered signal to generate a second rectified signal; and

a microprocessor configured to;

sample the first rectified signal;

determine a frequency of the output signal based on an amplitude of the first rectified signal;

sample the second rectified signal; and

determine a phase of the amplified output signal based on an amplitude of the second rectified signal.

10. The generator according to claim 9, wherein the first filter is one of a notch filter or a band-pass filter.

11. The generator according to claim 9, wherein the first filter is configured to attenuate the output signal as the frequency of the output signal shifts from the first center frequency.

12. The generator according to claim 9, wherein the output signal is a digital signal or an analog signal.