Amplified system for determining parameters of a patient
First Claim
1. In combination for providing at selective positions on a patient'"'"'s skin signals representing the patient'"'"'s parameters at these positions, an electrode constructed to be attached to the patient'"'"'s skin at the selective positions to provide signals indicative of the parameters on the patient'"'"'s body at the selective positions, an amplifier having an input terminal with an impedance approaching infinity and providing at the output terminal signals corresponding to the signals from the electrode, and an output stage connected to the amplifier and constructed to reject noise and to pass signals at frequencies below a particular value.
1 Assignment
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Accused Products
Abstract
An electrode is attached at a selective position to a patient'"'"'s body to provide signals representative of the patient'"'"'s parameters (e.g., electrocardiogram) at that position. The electrode signal may be in microvolts or millivolts. Depending upon the characteristics of the patient'"'"'s skin, the electrode impedance may vary to approximately 200 kilohms. The electrode signals pass to an amplifier having an input impedance (e.g., 1015 ohms) approaching infinity and a low output impedance The amplifier impedances insure that the electrode signal will pass through the amplifier without loss in signal strength and without change in signal characteristics. A low pass filter connected to the amplifier output eliminates noise and passes signals at low frequencies (e.g., 1 kilohertz). The filter and the amplifier are disposed on a printed circuit board with the amplifier physically and electrically isolated from the filter. Another low pass filter may be connected to the input of the amplifier.
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Citations
34 Claims
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1. In combination for providing at selective positions on a patient'"'"'s skin signals representing the patient'"'"'s parameters at these positions,
an electrode constructed to be attached to the patient'"'"'s skin at the selective positions to provide signals indicative of the parameters on the patient'"'"'s body at the selective positions, an amplifier having an input terminal with an impedance approaching infinity and providing at the output terminal signals corresponding to the signals from the electrode, and an output stage connected to the amplifier and constructed to reject noise and to pass signals at frequencies below a particular value.
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6. In a combination for providing signal at selective positions on a patient'"'"'s skin of the patient'"'"'s parameters at the selective positions,
an electrode constructed to be applied to the selective positions of the patient'"'"'s skin to provide a signal representative of the patient'"'"'s parameters at these selective positions, an amplifier connected to the electrode to amplify the signals at the electrode, and a low pass filter connected to the amplifier to provide an output in which noise is eliminated and signals in a particular frequency range are passed by the low pass filter, the amplifier having characteristics of providing a high input impedance and a low output impedance.
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13. In combination for providing at selective positions on a patient'"'"'s skin signals representing the patient'"'"'s parameters at these positions,
a first electrode constructed to be attached to the patient'"'"'s skin at the selective positions to provide signals representing the patient'"'"'s parameters at these positions, a second electrode constructed to be attached to the patient'"'"'s skin at positions different from the selective positions to provide reference signals, amplifiers connected to the first and second electrodes and having properties of providing a high input impedance approaching infinity and having a low output impedance, and a high pass filter connected to the amplifiers for eliminating noise and for passing signals at relatively high frequencies.
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21. In combination for providing at selective positions on a patient'"'"'s skin first signals representing the patient'"'"'s parameters at these positions,
a first electrode coupled to the patient'"'"'s skin at one of the selective positions for producing first signals representing the patient'"'"'s parameter at this position, a second electrode coupled to the patient'"'"'s skin at a position other than the selective position for producing reference signals, a first amplifier coupled to the first electrode for amplifying the first signals, the first amplifier having an input impedance approaching infinity, and a second amplifier coupled to the second electrode for amplifying the second signals, the second amplifier having an input impedance approaching infinity, and a differential circuit connected to the first and second amplifiers to eliminate noise and to produce an output signal representing the difference between the first and second signals.
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25. In combination for providing at selective positions on a patient'"'"'s skin first signals representing the patient'"'"'s parameters at these positions,
an electrode coupled to the patient'"'"'s skin at one of the selective positions for producing second signals representing the patient'"'"'s parameters at this position, and an amplifier connected to the first electrode for amplifying the signals from the electrode, the amplifier having an input impedance approaching infinity.
Specification