Communications: electrical – Continuously variable indicating – Condition responsive
Patent
1986-03-31
1987-08-25
Caldwell, Sr., John W.
Communications: electrical
Continuously variable indicating
Condition responsive
34087016, 340573, 128736, 331 66, B08C 1900
Patent
active
046896210
ABSTRACT:
A temperature responsive transmitter is provided in which frequency varies linearly with temperature. The transmitter includes two identically biased transistors connected in parallel. A capacitor, which reflects into the common bases to generate negative resistance effectively in parallel with the capacitor, is connected to the common emitters. A crystal is effectively in parallel with the capacitor and the negative resistance. Oscillations occur if the magnitude of the absolute value of the negative resistance is less than the positive resistive impedance of the capacitor and the inductance of the crystal. The crystal has a large linear temperature coefficient and a resonant frequency which is substantially less than the gain-bandwidth product of the transistors to ensure that the crystal primarily determines the frequency of oscillation. A high-Q tank circuit having an inductor and a capacitor is connected to the common collectors to increase the collector current flow which in turn enhances the radiation of the oscillator frequency by the inductor.
REFERENCES:
patent: 3158027 (1964-11-01), Kibler
patent: 3323513 (1965-02-01), Gnadke
patent: 3534728 (1970-10-01), Barrows
patent: 3739279 (1973-06-01), Hollis
patent: 4107625 (1978-08-01), Courier de Mere
patent: 4177800 (1979-12-01), Enger
patent: 4456892 (1984-06-01), Vandergraaf
patent: 4560959 (1985-12-01), Rokos et al.
patent: 4574205 (1986-03-01), Nagano
J. R. Riley-"Crystal-Controlled, Surgically Implantable, Temperature Telemetry Transmitter"--Medical & Biological Engineering & Computing--May 1980, pp. 363-364.
Donaldson et al-"Silicone-Rubber Adhesive as Encapsulants for Microelectronic Implants; Effect of High Electric Fields and of Tensile Stress"--Medical & Biological Engineering & Computing-Nov. 1977--pp. 712-715.
Ramey et al--"A Temperature Monitoring System for Use on Normal Newborn Infants"--IEEE Trans. Instrum. & Meas. (U.S.A.), vol. 1M-21, No. 1 (Feb./1972).
Fenton--"Remote Temperature Measurements"--Instruments and Control Systems--vol. 43, No. 6--Jun. 1970.
Cupal et al--"A Pulsed Carrier Dual Channel; Biotelemetry System for Bouvine Nutrition Studies"--8th ISA Biomedical Sciences Instrumentation Symposium--May 1970--pp. 194-200.
Novinskii et al--"Quartz Thermometer with Oscillator Based on Field-Effect Transistors"--Instrum. & Exp. Tech. (U.S.A.), vol. 20, No. 3, pp. 2, 909-910, Dec. 1977.
Caldwell Sr. John W.
Fatahi-Yar Mahmoud
Lupuloff Harry
Manning John R.
The United States of America as represented by the Administrator
LandOfFree
Temperature responsive transmitter does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Temperature responsive transmitter, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Temperature responsive transmitter will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1925967