Document
-. 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
Internal Transformers (40PHz Option) No Trims or Adjustments Necessary
APPLICATIONS Driving Control Transformers Driving Torque Receivers (with External Amplifiers)
OServo Mechanisms
Retransmission Systems
BPositional Control SGENERAL DESCRIPTION OThe DSC1705 and DSC1706 are Digital-to-Synchro and Digital-
to-Resolver converters capable of driving electromechanical
Lloads of up to 1.3VA. EThey accept a 14- or 12-bit digital input representing angle Tand a reference voltage of either 60Hz or 400Hz, and produce Ea 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).
REFERENCE
TRANS. FORMERS
SCOTT
TEE TRANSFORMERS
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 specified 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.
Model
DSC170S
DSC1706
ACCURACY.
:1:4arc-minutes
:t8 arc-minutes
RESOLUTION INPUT CODE
14 Bits (lLSB =1.3 arc-minutes) M14S-BB=its1N80a°tural ParallelBinarywith
12 Bits (lLSB = 5.3 arc-minutes)
M12S-BBi=ts
Natural 180°
Parallel
Binary
with
REFERENCE VOLTAGE INPUT With Internal Transformers . Low Level
High Level External Transformer Options2
REFERENCE FREQUENCY
26V rms 115V rms 4V rms
60Hz or 400Hz
..
.
.
REFERENCE INPUT IMPEDANCE
With Internal Transformers Low Level .
High Level External Transformer Options2
DIGITAL IN,PUT(TTL COMPATIBLE)
OUTPUT VOLTAGE AND FORMAT With Internal1ransformers Low Level
OHigh Level BExternal :Transformer Options3 SLOAD CAPABILITY OSHORT CIRCUIT PROTECTION LOUTPUT SETTLING TlME4 ERADIUS VECTOR VARIATION
(Transformation Ratio)
TEINTERNAL TRANSFORMER ISOLATION
20kQ 200kQ lOkQ lTTL Load
11.8V rms Line-to-Line Synchro or Resolver
90V rms Line-o-Line Synehro or Resolver
7V rms Sineand Cosine
1.3VA ContlDuousfor 5 minutes
°
50/Js for 180 Step to.1% max Sineand Cosine
500V de
. . . .
.
.
. . . . .
.
POWER SUPPLIES Voltage Current. (a) No Load (b) Full Load Mean
WARM-UP TIME
OPERATING TEMPERATURE RANGE
STORAGE TEMPERATURE RANGE SIZE
t15V de :1:5%
95mA per Line 225mAper Line
lsee to Full Accuracy
0 to +700C
Standard
-55°C to +105°CExtended
-55°C to +125°C
3.125" x 2.625" x 0.8" (79.4mm x 66.7mm x 20.3mm)
.
.
.
.
. . .
. .
WEIGHT
MEAN TIME BETWEEN FAILURES (MTBF) CALCULATED
8 ounces(224 grams)max 150,000 Hours
. .
NOTES
.Specifications same as DSC1705. I Accuracy applies over the full operating temperature range
of the option and for: (a) :1:10%reference frequency and amplitude variation. (b) 10% harmonic distortion on the reference.
(c) :t5% power supply variation. (d) Any balanced load from no load to full load.
2 Refers to input to converter and not to external transformers. 3 Refers to output from internal converter amplifiers and not from
external transformers. .