Tunnel diode oscillator applied as sensor-modulator for telemetry of temperature in human beings and animals

The purpose of this study was to use the tunnel diode in order to evaluate objectively the temperature in human beings and animals based on the region of negative resistance of the tunnel diode, we have designed and developed a relaxation tunnel diode oscillator circuit (astable) that acts as sensor and modulator of its oscillation frequency. The modulated signal corresponding to the temperature is transmitted by radio telemetry in FM. The prove of the system was carried out in animal test (rat), where the tunnel diode (sensor-modulator) was implanted. The range of temperature of the tunnel diode as a sensor of temperature was characterized of 0 /spl deg/C to 50 /spl deg/C with a resolution of 0.03 /spl deg/C and an accuracy of /spl plusmn/0.1 /spl deg/C. Additionally, measurements of temperature of the human skin using the same tunnel diode were obtained.