APPARATUS FOR TELEMETERING OF EKG SIGNALS FROM MOBILE STATIONS
First Claim
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1. A telemetering system for transmission of physiological parameters having normal periods, such as EKG signals having QRS portions, including:
- a. means for amplifying signals from a physiological parameter having a period, b. means for converting said signals into pulses of varying width, c. an fm radio transmitter, d. the output of said converting means (b) modulating said transmitter, e. means for measuring the period of the parameter and switch means for controlling the transmission by said radio of said signals, f. means for actuating said transmitter switch when a subsequent value of the periodicity of said parameter departs greater than a predetermined amount from an initial periodicity of said parameter, g. a ramp generator, h. a reference periodic voltage being generated by the ramp generator, i. means for diminishing to zero said ramp voltage with a period initiating change in said parameter, j. a first Zener diode in a path between said ramp generator and switch means for conducting said ramp voltage to actuate said switch means, when a subsequent periodicity of the parameter increases beyond the reference periodicity, k. means for supplying an operating potential apart from the ramp generator to actuate said switch means, l. means for shunting said operating potential to ground, said means including a second Zener diode, having a lower breakdown voltage than said first Zener, which is in a line defining a first shunt to ground, m. a second shunt means to ground, parallel with said first shunt to ground, said second shunt being normally closed and opened only upon a period initiating change in the parameter.
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Abstract
A system for the radio transmission of EKG signals to a hospital from an ambulance. After an initial limited transmission of EKG waves, no further signals are transmitted unless the EKG (R-R) rate departs significantly from the initial rate. The EKG signals modulate a voltage controlled oscillator. A code is associated with the transmission to identify patient, rescue vehicles and hospital.
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Citations
6 Claims
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1. A telemetering system for transmission of physiological parameters having normal periods, such as EKG signals having QRS portions, including:
- a. means for amplifying signals from a physiological parameter having a period, b. means for converting said signals into pulses of varying width, c. an fm radio transmitter, d. the output of said converting means (b) modulating said transmitter, e. means for measuring the period of the parameter and switch means for controlling the transmission by said radio of said signals, f. means for actuating said transmitter switch when a subsequent value of the periodicity of said parameter departs greater than a predetermined amount from an initial periodicity of said parameter, g. a ramp generator, h. a reference periodic voltage being generated by the ramp generator, i. means for diminishing to zero said ramp voltage with a period initiating change in said parameter, j. a first Zener diode in a path between said ramp generator and switch means for conducting said ramp voltage to actuate said switch means, when a subsequent periodicity of the parameter increases beyond the reference periodicity, k. means for supplying an operating potential apart from the ramp generator to actuate said switch means, l. means for shunting said operating potential to ground, said means including a second Zener diode, having a lower breakdown voltage than said first Zener, which is in a line defining a first shunt to ground, m. a second shunt means to ground, parallel with said first shunt to ground, said second shunt being normally closed and opened only upon a period initiating change in the parameter.
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2. The system of claim 1 wherein, a. said means (e) includes means for supplying a potential for actuating said radio switch means, a first switch normally shunting said potential to ground but which opens and fails to shunt upon a period initiating change in the parameter, and a second switch normally open but which shunts said potential to ground when said reference voltage exceeds a predetermined value.
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3. A telemetering system for transmission of physiological parameters having periods, such as EKG signals having QRS portions, including:
- a. means for generating a periodic reference voltage corresponding to an initial periodicity value of said parameter, b. a radio transmitter having a radio transmission switch, c. means for energizing the radio transmission switch by said periodic reference voltage when it exceeds a first predetermined value, d. a second voltage source for energizing said radio transmission switch, e. means shunting to ground said second voltage source except upon period initiating changes in said parameter, f. means for shunting to ground said second voltage source when said periodic reference voltage exceeds a second and lower predetermined value, g. whereby the radio transmission switch is energized and signals corresponding to the physiological parameter are trans-mitted when subsequent periodicity values of the parameters depart from initiAl periodicity values by an amount greater than half of the difference between the first and second predetermined values.
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4. The system of claim 3 including, a. means for visually presenting the periodic reference voltage.
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5. A telemetering system for transmission of physiological parameters having normal periods, such as EKG signals having QRS portions, including:
- a. means for amplifying signals from a physiological parameter having a period, b. means for converting said signals into an audible frequency, of variable pitch, in the range 600 to 2000 Hz, c. an fm radio transmittter, d. the output of said converting means (b) modulating said transmitter, e. means for measuring the period of the parameter and switch means for controlling the transmission by said radio of said signals, f. means for actuating said transmitter switch when a subsequent value of the periodicity of said parameter departs greater than a predetermined amount from an initial periodicity of said parameter, said (f) means including a ramp generator, a reference periodic voltage being generated by the ramp generator, means for diminishing to zero said ramp voltage with a period initiating change in said parameter, g. a first Zener diode in a path between said ramp generator and switch means for conducting said ramp voltage to actuate said switch means, when a subsequent periodicity of the parameter increases beyond the reference periodicity, h. means for supplying an operating potential apart from the ramp generator to actuate said switch means, i. means for shunting said operating potential to ground, said means including a second Zener diode, having a lower breakdown voltage than said first Zener, which is in a line defining a first shunt to ground, j. a second shunt means to ground, parallel with said first shunt to ground, said second shunt being normally closed and opened only upon a period initiating change in the parameter.
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6. The system of claim 5 wherein, a. said means (e) includes means for supplying a potential for actuating said radio switch means, a first switch normally shunting said potential to ground but which opens and fails to shunt upon a period initiating change in the parameter, and a second switch normally open but which shunts said potential to ground when said reference voltage exceeds a predetermined value.
Specification