DSC1705_15 Datasheet, PDF (1/4 Pages) Analog Devices – DIGITAL TO SYNCHRO CONVERTERS

-. ANALOG
W DEVICES
Digital- to-Synchro
Converters
I
DSC1705/1706 I
FEATURES
Very Low Radius Vector Variation (Transformation
Ratio) (:to.1%)
High Accuracy (:t2 arc-mins at +25°C)
12- or 14.Bit Resolution
No 5 Volt Power Supply Required
MIL Spec/Hi Rei Versions Available
Internal 1.3VA Amplifiers
OBSOLETE ^{Internal Transformers (40PHz Option)}
No Trims or Adjustments Necessary
APPLICATIONS
Driving Control Transformers
Driving Torque Receivers (with External Amplifiers)
Servo Mechanisms
Retransmission Systems
Positional Control
GENERAL DESCRIPTION
The DSC1705 and DSC1706 are Digital-to-Synchro and Digital-
to-Resolver converters capable of driving electromechanical
loads of up to 1.3VA.
They accept a 14- or 12-bit digital input representing angle
and a reference voltage of either 60Hz or 400Hz, and produce
a 3 wire or 4 wire output suitable for driving Synchros or
MODELS AVAILABLE
The two Digital to Synchro/Resolver converters described in
this data sheet differ primarily in the areas of resolution and
accuracy as follows:
Model DSC1705XYZ is a 14-bit converter with an overall
accuracy of :t4 arc-minutes.
Model DSC 1706XYZ is a 12-bit converter with an overall
Resolvers.
accuracy of 18 arc-minutes.
The 400Hz converters contain internal1.3V A amplifiers as
well as output and reference transformers.
The 60Hz versions contain internal 1.3VA amplifiers but
require external output and reference transformers.
If it is necessary to drive a load requiring more than 1.3VA,
options for both the 400Hz and 60Hz converters are available
allowing the use of external amplifiers and transformers.
The XYZ option code defines the option thus: (X) signifies
the operating temperature range, (Y) signifies the reference
frequency, (Z) signifies the output and the reference voltages,
whether the output is in ~ynchro or Resolver format and
whether external transformers are required.
II
RHi
RADIUS VECTOR
One of the outstanding features of these converters is the
almost negligible Radius Vector variation (Transformation
Ratio).
REFER-
ENCE
TRANS.
FORMERS
SCOTT
TEE
TRANS-
FORMERS
53
On many Digital-to-Synchro converters presently available, the
individual sine and cosine outputs produced do not follow the
exact sine and cosine laws, and depending upon angle can vary
up to :t7%. This is not always important as the ratio of the sine
to the cosine, i.e., the tangent, is always correct to the speci-
fied accuracy of the converter. There are cases however, when
driving torque receivers and certain servo control loops when
this variation is unacceptable.
"^MSB
/
OIGiTAL INPUT WI
Principle of Operation
FUNCTIONAL DIAGRAM, DSC170S and DSC1706
The principle of operation of the converters described in
this data sheet is shown in the diagram above.
The design of the DSC1705 and DSC1706 has reduced this
variationto lessthan to.l%. This meansthat when the
convertersare usedin closedloop servosystems,the gain of
the closed loop is independent of the digital input angle, thus
making reference correction unnecessary.