A SPACEBORNE ANALOG TO DIGITAL CONVERTER DESIGN.
JOHNS HOPKINS UNIV SILVER SPRING MD APPLIED PHYSICS LAB
Pagination or Media Count:
A nine bit analog to digital converter was designed for the DME-A satellite. This analog to digital converter uses the successive approximation principle to convert an analog voltage to its equivalent state. TI integrated circuits are used in the digital logic. The analog portion contains a voltage comparator, constant current sources, their respective solid state switches, a precision ladder network, and plus and minus reference supply voltages. A conversion is made in 400 microsec with an accuracy specified to be plus or minus 2 of full scale linear. The outputs are 9 bits straight binary with all logical ones representing positive full scale of 275 mv and all logical zero representing negative full scale of -275 mv. Negative logic defines a zero to be high voltage, 3.5V, and a one to be low voltage, 0.5V for this design. Power for this device is required from the plus and minus twenty volts and plus four volts. Continuous power is about 45 of a watt. Normal operation requires a pulsed power of about 12 watt. Author
- Computer Hardware