Electronic thermometer

• US 3,972,237 A
• Filed: 05/28/1974
• Issued: 08/03/1976
• Est. Priority Date: 05/28/1974
• Status: Expired due to Term

• Current Assignee: American Medical Electronics, Inc. (Orthofix Medical Inc.)
• Original Assignee: American Medical Electronics, Inc. (Orthofix Medical Inc.)
• Inventors: Turner, Robert Bruce
• Primary Examiner(s): Queisser, Richard C.
• Assistant Examiner(s): Shoon, Frederick
• Application Number:
  US05/473,494
• Time in Patent Office: 798 Days
• Field of Search: 73/362 AR, 73/359, 73/432 CR, 340/347 M, 340/382, 340/807, 340/645
• US Class Current: 374/169
• CPC Class Codes: G01K 1/028 arrangements for numerical indication
• CPC Class Codes: G01K 7/24 in a specially-adapted circuit, e.g. bridge circuit

Abstract

An electronic thermometer system comprising a temperature sensing circuit for providing an analog signal representative of the temperature being sensed; a voltage to rate converter circuit responsive to the analog signal for providing uniform digital pulses at a repetition rate proportional to the temperature being sensed; and means for counting the digital pulses for a predetermined period of time for providing an indication of the temperature being sensed.

Claims

1. An electronic thermometer system comprising:

a temperature sensing circuit for providing an analog signal representative of the temperature being sensed;

a voltage to rate converter circuit responsive to said analog signal for providing constant width and amplitude pulses at a repetition rate which is proportional to the temperature being sensed, including an integrating circuit, having a first input for receiving said analog signal and a second input for receiving a reference input, responsive to a difference between said first and second inputs for providing a voltage proportional to that difference;

a pulse generating circuit for producing pulses of constant width and amplitude, each said pulse provided in response to a predetermined output level of said integrator; and

a feedback circuit for introducing each said pulse to one of said first and second inputs to reduce the difference between said first and second inputs and reset said integrating circuit; and

means for counting said pulses for a predetermined period of time for providing an indication of the temperature being sensed.

2. An electronic thermometer system comprising:

a temperature sensing circuit for providing an analog signal representative of the temperature being sensed;

a voltage to rate converter circuit responsive to said analog signal for providing constant width and amplitude pulses at a repetition rate which is proportional to the temperature being sensed, including an integrating circuit, having a first input for receiving said analog signal and a second input for receiving a reference input, responsive to a difference between said first and second inputs for providing a voltage proportional to that difference;

a pulse generating circuit for producing pulses of constant width and amplitude, each said pulse produced in response to a predetermined output level of said integrator; and

a feedback circuit for introducing each said pulse to one of said first and second inputs to reduce the difference between said first and second inputs and reset said integrating circuit;

including an RC network which includes capacitive and resistive impedance components interconnecting said temperature sensing circuit and said voltage to rate converter circuit, which has a current characteristic inverse, and similar to, the thermal time constant of said temperature sensing circuit, and which is responsive to said analog signal representative of the temperature being sensed to increase the current flow to said voltage to rate converter circuit for driving the system to indicate the final value temperature before that temperature is actually measured.