A logarithmic response resistor-capacitor telemetry modulator
Abstract
A unique electronic circuit has been developed for use in a rocket-borne temperature sonde to convert a thermistor resistance to a modulation frequency for telemetry application. The modulator's frequency versus resistance curve drifts less than 4% as the temperature of the electronics varies from +60C to -60C. The drift is easily corrected by including a reference circuit in the sonde. The modulator can be made almost entirely insensitive to power supply voltage changes, and can be made to dissipate less than 0.1-microwatt power in the thermistor without degrading resolution, temperature stability, or voltage stability. Because it passes alternating current through the thermistor, it possesses a nearly logarithmic frequency versus resistance curve with a resistor-capacitor (R-C) network instead of a transistor.
- Publication:
-
NASA STI/Recon Technical Report N
- Pub Date:
- April 1975
- Bibcode:
- 1975STIN...7610203B
- Keywords:
-
- Modulators;
- Radiosondes;
- Rocket-Borne Instruments;
- Telemetry;
- Atmospheric Temperature;
- Circuits;
- Ionospheric Sounding;
- Sounding Rockets;
- Space Communications, Spacecraft Communications, Command and Tracking