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Page Title:
Digital-to-Analog Signal Converters |
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|  MIL-W-85057(AS)
3.5.2.1.2 Analog-to-Digital Signal Converter. The A/D converter
under program control shall be capable of converting two input signals
concurrently.
These two signals shall be multiplexed from five pairs of
external analog inputs (including two spare inputs). Five pairs of signa1s
from within the WDC shall also be selectable from the multiplexer for BIT
purposes. The input impedance shall be greater than 10 megohms and the
input voltage range shall be + 10 V. The output format shall be sign
magnitude with 14 bits, consisting of one sign bit, one overrange bit,
and twelve magnitude bits. The bit weights shall be 10 V (nominal) for
the overrange bit, 5 V (nominal) for the MSB of the magnitude. For any
positive input voltage (Vin), the A/D output shall be l ccurate to within
30 mV of the calculated value, 10 Vin per volt reference (Vref), where
Vref is the measured value of either positive reference voltage specified
herein. For any negative Vin, the A/D output shall be accurate to within
30 mV of the calculated value, -10 Vin/Vraf; where Vref is the measured
value of the negative reference voltage specified herein.
3.5.2.1.3 Conversion Time. For all inputs except the synchro inputs,
the conversion time for a pair of inputs shall not exceed 1.7 ma. For
synchro inputs, the total conversion time for l sin and cos pair of
inputs, including the time required to synchronize with the 400-Hz reference
voltages shall not exceed 4.4 me. The hardware shall be capable of completing
three pairs of synchro-to-digital conversions and five pairs of A/D conversions
in less than 19.6 ma.
3.5.2.1.4 Digital-to-Analog Signal Converters - Two D/A converters
shall be included in the CIU and shall be under program control. Each of
these converters shall have the following characteristics:
(1) Input format:
Two's complement, parallel.
(2) Resolution: 11 bits.
(3) Accuracy: + 5%
(4) Output voltage: + 2.5 V.
.
(5) Output load capability: 1000 ohms, minimum
(6) Conversion time: 1.0 M, maximum.
3.5.2.1.5 Reference Voltages. The CIU shall
provide the following
reference signals which shall be derived from the
+ 10 A/D converter reference
Voltage. The internal reference shall be 10 V +
60 mV. The magnitude of
the - 10 Vdc reference shall be within + 20 mV of
the + 10 Vdc reference No. 2.
(1) + 10 Vdc reference No. 1: 25 miliamperes (mA), maximum.
-38-
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