Physiological sensor and transmitter
First Claim
1. In a blocking oscillator for generating a sequence of bursts of oscillations, said blocking oscillator having an amplifying device that has a control element,a resonant circuit including an inductor and a tuning capacitor operatively connected to said amplifying device, said oscillator also including a blocking capacitor connected to said resonant circuit for developing a control bias;
- means for applying said control bias to said control element to quench said oscillations when the bias attains one value and to initiate said oscillations when said bias attains another value, said control capacitor charging in one direction while said oscillator is oscillating and in the other direction when said oscillator is quiescent to change said bias;
an isolation impedence connecting said blocking capacitor between said resonant circuit and said control element, whereby intermittent switching of the amplifying element on and off precludes intermittent direct connection and disconnection of said blocking capacitor across said resonant circuit, thereby concentrating the oscillations to a narrow band of frequencies determined by said tuning capacitor and said inductor substantially independently of said blocking capacitor.
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Accused Products
Abstract
A small self-contained sensor and transmitter assembly including a sensor for detecting physiological and bio-medical phenomena and a transmitter for transferring such data to a receiver for display and other use is disclosed. In one embodiment, the sensor is adapted to be secured within the axilla of a patient to detect his temperature by means of a thermistor arranged in heat exchange relation with the body of the patient. The thermistor modulates the pulsing rate of a blocking oscillator which generates a magnetic field, the pulsing rate being proportional to the physiological phenomenon of interest. The oscillator, power supply, antenna, and other circuit elements are mounted within corresponding compartments in a molded plastic housing, the arrangement being such that substantially all of the interconnections between circuit elements are made using only the component lead wires. The thermistor is mounted on the exterior surface of the housing and is thermally isolated from it to provide a fast response, and an adhesive is provided to secure the housing to the patient'"'"'s skin. A resilient cover on the housing provides thermal insulation and insures patient comfort. The transmitter circuitry is constructed for stable operation, fast response, and transmits data in a narrow frequency spectrum for accurate measurement.
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Citations
57 Claims
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1. In a blocking oscillator for generating a sequence of bursts of oscillations, said blocking oscillator having an amplifying device that has a control element,
a resonant circuit including an inductor and a tuning capacitor operatively connected to said amplifying device, said oscillator also including a blocking capacitor connected to said resonant circuit for developing a control bias; -
means for applying said control bias to said control element to quench said oscillations when the bias attains one value and to initiate said oscillations when said bias attains another value, said control capacitor charging in one direction while said oscillator is oscillating and in the other direction when said oscillator is quiescent to change said bias; an isolation impedence connecting said blocking capacitor between said resonant circuit and said control element, whereby intermittent switching of the amplifying element on and off precludes intermittent direct connection and disconnection of said blocking capacitor across said resonant circuit, thereby concentrating the oscillations to a narrow band of frequencies determined by said tuning capacitor and said inductor substantially independently of said blocking capacitor. - View Dependent Claims (2)
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3. In a blocking oscillator for generating a sequence of bursts of oscillations of radio frequency, including an amplifying device in the form of a solid-state element having a control electrode and an output electrode, the oscillator having a tuned circuit including an inductor and a tuning capacitor operatively connected to said electrodes, the improvement comprising:
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a bias control circuit for said oscillator including an isolating resistor and a blocking capacitor connected between said tuned circuit for said control electrode for developing a control bias in accordance with the oscillations in said tuned circuit, wherein the bias on said control electrode charges in one direction while said oscillator is oscillating, finally attaining a bias which quenches said oscillations, and charges in the other direction when said oscillator is quiescent, to reach a value at which oscillations are initiated; and high voltage means connected between said output electrode and said control electrode for stabilizing the time between successive ones of said bursts. - View Dependent Claims (4, 5)
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6. In a blocking oscillator for generating a sequence of bursts of oscillations of radio frequency at a burst rate that corresponds to the value of a physiological parameter of a subject, said oscillator having an amplifying device in the form of a solid-state element having a control electrode and an output electrode and a tuned circuit including an inductor and a tuning capacitor operatively connected to said electrodes, said oscillator including a sensing element having a resistance that varies in accordance with the value of said parameter, the improvement comprising:
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a storage capacitor connected to said tuned circuit for developing a control bias in accordance with the strength and duration of oscillations in said tuned circuit; and a bias control circuit including said sensing element and a resistor connected to said control electrode and to said blocking capacitor whereby said control capacitor changes the bias on said control electrode in one direction while said oscillator is oscillating, finally reaching a bias which quenches said oscillations, and in the other direction when said oscillator is quiescent, to reach a value at which oscillations are initiated, the rate of change of bias while said oscillation is quiescent varying in accordance with the value of said sensing element. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. In a physiological testing unit to be secured to a subject:
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a blocking oscillator for generating a sequence of bursts of oscillations at a burst rate that corresponds to the value of a physiological panameter of the subject, said oscillator having an amplifying device including a control electrode and an output electrode and having a resonant circuit operatively connected to said electrodes, said resonant circuit including an antenna winding adapted to emit signals corresponding to said oscillations; a blocking capacitor connected to said resonant circuit for developing a control bias; a bias control circuit including a sensing element responsive to said parameter connected to said control electrode and to said blocking capacitor, said bias control circuit changing the bias on said control electrode in one direction while said oscillator is oscillating, finally reaching a bias level which quenches said oscillations, and changes the bias level on said control electrode in the other direction when said oscillator is quiescent, finally reaching a bias level at which oscillations are initiated, the rate of change of bias level while said oscillator is quiescent varying in accordance with the value of the parameter detected by said sensing element whereby said burst rate varies with the value of said parameter; a housing enclosing said oscillator; means mounting said sensing element exteriorly of said housing; and means for externally removably attaching said unit to the subject, said sensing element being mounted on the housing to detect a desired physiological parameter of the subject and being connected to said oscillator bias control circuit to modulate said signals in accordance with such parameter. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 40, 41, 42, 43, 44, 45, 46, 47, 48)
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25. A small, self-contained physiological testing unit to be externally secured to a patient and adapted to transmit signals corresponding to the temperature of the patient, comprising:
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a thermistor adapted to be placed adjacent the surface of the patient'"'"'s skin to detect its temperature, said thermistor having a pair of electrodes; an oscillator circuit having an antenna winding, said oscillator being controlled by the thermistor to inductively transmit signals modulated in accordance with the detected temperature; a tubular iron core composed of powdered iron particles held together with an electrically insulating, non-magnetic binder, said winding being wound on the outside of said core; a power supply for said oscillator circuit including a battery fitting snugly within said core; a dimensionally rigid case member formed with a plurality of internal cavities, each cavity being formed to receive a corresponding one of said core and of said electrical components making up said oscillator circuit, said cavities locating said components in such a way that substantially all electrical connections for said oscillator circuit may be made by means of the lead wires on said components; means for mounting said thermistor on the exterior of said case member, said thermistor electrodes being connected through said case member to said oscillator circuit; battery cover means for securing said battery within said case member; a flexible, flanged cover secured to said rigid case member and together with said case providing thermal insulation for said electrical components, said cover providing a pliant outer cover for the testing unit; and a thin adhesive member having adhesive on both sides, one side of the adhesive member being secured to the bottom of the flanged cover and to said case member, said unit being adapted to be secured externally to the patient by the adhesive member with said thermistor adjacent the patient'"'"'s skin. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36)
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- 37. For an oscillator of a radio frequency transmitter, a winding wound on a tubular magnetic core that encircles a miniature battery, said core being composed of carbonyl iron.
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49. In a physiological testing unit to be secured to a subject:
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a blocking oscillator including an amplifying device having a control element for generating a sequence of bursts of oscillations, said oscillator including a resonant circuit operatively connected to said amplifying device and including an antenna winding and a tuning capacitor adapted to emit signals corresponding to the detected physiological condition; a blocking capacitor connected to said resonant circuit for developing a control bias; means for applying said control bias to said control element to quench said oscillations when said bias attains one value and to initiate said oscillations when said bias attains another value, said blocking capacitor charging in one direction while said oscillator is oscillating and in the other direction when said oscillator is quiescent to change said bias; an isolation impedance connecting said blocking capacitor between said resonant circuit and said control element whereby intermittent switching of the amplifying device on and off precludes intermittent direct connection and disconnection of said blocking capacitor across said resonant circuit, thereby concentrating the oscillations to a narrow band of frequencies determined by said tuning capacitor and said antenna winding substantially independently of said blocking capacitor; a housing enclosing said oscillator circuit; means for externally removably attaching said unit to the subject; and a sensing element mounted on the housing to detect a desired physiological parameter of the subject and connected to said oscillator to modulate said emitted signals in accordance with such parameter. - View Dependent Claims (50, 51, 52, 53, 54, 55, 56)
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57. A physiological testing unit including a transmitter having a blocking oscillator for generating a sequence of bursts or oscillations of radio frequency and including an amplifying device in the form of a solid-state element having a control electrode and an output electrode, the oscillator having a tuned circuit including a transmitter antenna and a tuning capacitor operatively connected to said electrodes;
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a bias control circuit for said oscillator including an isolating resistor and a blocking capacitor connected between said tuned circuit for said control electrode for developing a control bias in accordance with the oscillations in said tuned circuit, wherein the bias on said control electrode charges in one direction while said oscillator is oscillating, finally attaining a bias which quenches said oscillations, and charges in the other direction when said oscillator is quiescent, to reach a value at which oscillations are initiated; high voltage means connected between said output electrode and said control electrode for stabilizing the time between successive ones of said bursts; variable impedance means connected between said high voltage means and said blocking capacitor to control the rate of charging of said blocking capacitor while said oscillator is quiescent, whereby the time between successive ones of said bursts is varied in accordance with a parameter sensed by said variable impedance; a housing enclosing said blocking oscillator, bias control circuit and high voltage means; means for mounting said impedance means on the exterior of said housing; and means for securing said housing externally on a subject whose temperature is to be sensed with said impedance means in contact with said subject, whereby said testing unit transmits bursts of oscillations having a time rate which corresponds to the temperature being sensed.
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Specification