normally represent a quantity based on their amplitude
with respect to a reference voltage. Scalar signals
consist of two waveforms that represent the sine and
cosine of an angle. The device that performs these types
of conversions is a digital-to-analog converter (DAC).
The DAC may be either a component of a larger
device or a stand-alone equipment such as the
Digital-to-Analog Converter CV-2517B/UYK.
Digital-to-synchro conversion is required when
communicating with systems that use synchro data
transmission.
Digital-to-synchro converters are
usually found as components of multipurpose
conversion equipment.
However, a DAC may be
modified with a scott-tee transformer to generate
synchro signal outputs from scalar voltage waveforms.
DIGITAL-TO-LINEAR/SCALAR
CONVERSION
A digital-to-analog converter (DAC) is a device
that receives digital information in the form of a binary
word and transforms that information into variations of
an analog signal. The DAC outputs an analog signal
derived from a reference signal. Normally both the
converter and the analog device receiving the data
operate off of the same reference. The reference signal
is normally greater than or equal to the maximum limit
of the output of the converter.
The continuous output signal is varied in steps
based on the binary inputs to the converter. BAMs are
normally used as the binary input for CDS DACs. As
a bit position changes in the binary data, the output
signal is stepped up or down, based on the value of the
bit position or bit positions changed in the input. The
output signal only changes when the input data changes.
Each converter outputs a single proportional
voltage signal.
This signal is suitable for linear
operations. Two converters are required for scalar or
synchro conversions.
Two separate proportional
voltages must be developed to represent the scalar
sine/cosine angle which may in turn be fed to a scott-tee
transformer to generate a 3-wire synchro signal.
THE DIGITAL-TO-ANALOG CONVERTER
CV-2517B/UYK
The Digital-to-Analog Converter (DAC)
CV-2517B/UYK is a multipurpose converter capable
of accepting parallel digital data and converting it to
400-HZ linear, resolver, or synchro outputs. The DAC
(figure 13-5) provides the means for digital combat
direction systems to communicate with analog gun,
electronic countermeasures (ECM), or sonar
subsystems.
Figure 13-5.—DACs and mounting base.
13-8
