Automatic electrode channel impedance measurement system for egg monitor
First Claim
1. An impedance measurement system for measuring impedance of at least one electrode channel for use in a recorder of signals comprising:
- means for generating complementary oscillating signals, said complementary oscillating signals defining at each transition of said oscillating signals an assertion time, said recorder having at least one pair of electrodes, said at least one pair of electrodes being connectably applied to a subject'"'"'s body, said subject'"'"'s body and said at least one pair of electrodes defining said at least one electrode channel, said at least one electrode channel cooperating with said means for generating complimentary oscillating signals to monitor and record said signals;
conditioning means for producing a pair of attenuated and filtered complementary oscillating signals based upon the complementary oscillating signals;
signal generating means for converting said pair of attenuated and filtered signals into oscillating load-independent currents and applying said oscillating load-independent currents to said electrode channel to produce a responsive signal representative of impedance of said electrode channel;
amplification and filtering stage means for amplifying and filtering said responsive signal for generating a time-dependent signal;
threshold means for ascertaining a reset time at which said time-dependent signal crosses a threshold level;
timing means for measuring a time interval between said assertion time and said reset time; and
converting means for converting said time interval into an impedance value.
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Accused Products
Abstract
An impedance measurement system for electrocardiographic recorders which allows measurement of the electrode channel impedance without the need for a separate piece of equipment. The impedance measurement system, which is an integral part of the recorder, applies complementary oscillating currents having short transition times to an electrode channel defined by a pair of electrode leads, a pair of electrodes and the patient tissues. The analog current signals flowing through the electrode channel create a voltage across the electrode channel which is amplified and applied to a dual range filtering stage. The low range section of the dual range filtering stage generates a time-dependent signal which causes the output of the low range filtering circuit to produce a signal applied to the timing input of a microprocessor. The microprocessor calculates the time elapsed between each transition of the oscillating current signals and the occurrence of a signal at the output of the low range filtering circuitry. From that elapsed time, the microprocessor calculates the impedance of the electrode channel being monitored. In addition, in response to the signal appearing at the output of the high range section of the dual range filtering stage, the microprocessor verifies contemporaneously the integrity of the electrode leads in order to validate the measured impedance value.
100 Citations
8 Claims
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1. An impedance measurement system for measuring impedance of at least one electrode channel for use in a recorder of signals comprising:
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means for generating complementary oscillating signals, said complementary oscillating signals defining at each transition of said oscillating signals an assertion time, said recorder having at least one pair of electrodes, said at least one pair of electrodes being connectably applied to a subject'"'"'s body, said subject'"'"'s body and said at least one pair of electrodes defining said at least one electrode channel, said at least one electrode channel cooperating with said means for generating complimentary oscillating signals to monitor and record said signals; conditioning means for producing a pair of attenuated and filtered complementary oscillating signals based upon the complementary oscillating signals; signal generating means for converting said pair of attenuated and filtered signals into oscillating load-independent currents and applying said oscillating load-independent currents to said electrode channel to produce a responsive signal representative of impedance of said electrode channel; amplification and filtering stage means for amplifying and filtering said responsive signal for generating a time-dependent signal; threshold means for ascertaining a reset time at which said time-dependent signal crosses a threshold level; timing means for measuring a time interval between said assertion time and said reset time; and converting means for converting said time interval into an impedance value. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method to selectively measure impedance of at least one pair of electrodes, said at least one pair of electrodes being operatively connected to a subject'"'"'s body, said subject'"'"'s body and said at least one pair of electrodes defining an electrode channel, comprising the steps of:
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producing complementary oscillating load-independent current signals defining at each transition of said oscillating current an assertion time; applying said current signals to said electrode channel; monitoring a first voltage produced by the application of said current signals to said electrode channel; amplifying and filtering said first voltage to obtain a time-dependent voltage; establishing a DC threshold voltage; comparing said time-dependent voltage to said threshold voltage to generate, at a reset time, a timing signal indicative of a point at which said time-dependent voltage crosses said threshold voltage; measuring a time interval between said assertion time and said reset time; converting said time interval to an impedance value; and displaying said impedance value.
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Specification