Introduction
The DBS 8750 is a high speed (400 kHz), 16-bit, precision, dual channel
Arbitrary Waveform Synthesizer. Fully compatible with VXI specification Rev.
1.3, the DBS 8750 occupies a single "C" size slot in a VXI chassis. Highly accu-
rate standard and arbitrary waveforms are generated for use in a variety of de-
manding applications such as acoustical signatures, vibration analysis, complex
signal generation, automatic test equipment, linear device testing, digital com-
munications, and biomedical signal simulation.
Combining the superior performance of a dual digital-to-analog converter
(DAC), with a 100 dB dynamic range, and the speed and processing capability
of the TMS320C30 digital signal processor (DSP), the DBS 8750 provides pre-
cise, direct digital synthesis (DDS) of analog signals at an economically attrac-
tive price.
For maximum flexibility, three sources of digital data are supported for arbitrary
waveform generation and signal processing: downloaded data from VXI-resi-
dent memories, calculated data from the resident DSP, and local bus trans-
ferred data via connector P2 from other adjacent cards such as the Analogic
DBS 87xx family of VXI digitizer modules.
This multiple sourcing of waveform data, complemented by versatile triggering
and cross-synchronization capabilities, allows easy integration of precision ana-
log signal synthesis within sophisticated VXI instrumentation applications.
Software integration effort is reduced to an absolute minimum with the DBS 8750.
Message-based device architecture allows serial word communication protocols
with any Slot 0 Controller using Standard Commands for Programmable
Instruments (SCPI). A selection of available software drivers is offered for use
with the unit.
Features
u
16-Bit Precision
u
400 kHz Update Rate
u
Two Independent Outputs
u
500V Block Isolated Outputs
u
0.003% Differential Nonlinearity
u
High Performance DSP
u
Library of Standard Functions
u
SCPI Command Compatibility
u
Fully Compatible with the Analogic
DBS Series Modules
u
Software Drivers Available
Applications
u
Acoustic Signature
u
Automatic Test Equipment
u
Vibration Stimulus
u
Digital Communication
u
Biomedical Signal Stimulus
u
Linear Device Testing
u
Precision Audio Component Testing
Clock
Trig
Gate
Out 1
Out 2
Digital
Timing
&
Control
Output Stage 1:
Filter
Attenuator
Output Drive
Output Stage 2:
Filter
Attenuator
Output Drive
DAC 1
Waveform
Memory
32K Words
TTL Trigger Lines
Internal Data Bus
Mux
DSP/User
Shared
Memory
32K SRAM
17K User
Accessible
DC-to-DC
Converter
+5V
15V; +5V
Mux
DAC 2
Waveform
Memory
32K Words
Program
Memory
PROM
DSP
(TMS320C30)
Analog
Controls
DAC
1
DAC
2
V
X
I
I
N
T
E
R
F
A
C
E
Isolated
Figure 1. The DBS 8750 Block Diagram.
High Precision Arbitrary
Waveform Synthesizer
in a "C" Size VXI Module
DBS 8750
bus
ANALOG OUTPUTS
Number of Channels
2
Output Drive (programmable)
Single-ended or Differential
Output Voltage
10V Single-ended or Differential
(@ no load)
Maximum Load Current
40 mA
Crosstalk Ch. to Ch.
96 dB
Resolution
16 bit
Offset (programmable)
+10V to 10V in 1 LSB Steps
Attenuation (programmable):
0 dB to 30 dB in 0.01 dB steps.
Gain (filter bypass)
1 0.5%
Differential Non-Linearity
0.003% of FSR Max.
Output Impedance
(switch selectable)
50
or 600
Output Coupling
(switch selectable)
DC or AC
Isolation
300 VDC
STANDARD WAVEFORM
OUTPUTS
Sine Wave
Frequency
12.5 Hz to 20 kHz
Peak Distortion
2
96 dB @ 1.0 kHz
93 dB @ 20 kHz
Total Harmonic Distortion
3
94 dB @ 1.0 kHz
90 dB @ 20 kHz
Square Wave, Triangle Wave
Frequency
12.5 Hz to 30 kHz
Settling Time to 1 LSB after 10V
Step
16 s (output filter off)
Offset Voltage Typ.
20 mV
FILTERS
Filter Type
6 pole Butterworth
Modes of Operation
ON or bypass (programmable)
Pass Band Frequency
25 kHz (3 dB point)
Flatness in Pass Band
0.1 dB to 10 kHz Max.
0.25 dB to 20 kHz Max.
Attenuation in Stop Band
90 dB
Settling Time
250 s to 16 bit accuracy for 20
volt step function
STABILITY (0C TO +50C)
Required Warm-up Time
(for ultimate specifications)
15 minutes
Offset Tempco
23 V/C Typ.
75 V/C Max.
Gain Tempco
20 ppm FSR/C Typ.
40 ppm FSR/C Max.
Differential Nonlinearity Tempco
5 ppm FSR/C Max.
MEMORY
Waveform memory
(each channel)
32K words @ 16 bits
Shared DSP/User Memory
17K words for data transfers to/
from VXI memory or P2 local bus
TRIGGERING AND
SYNCHRONIZATION
External Clock (input #1)
Front Panel BNC (TTL) active low,
400 kHz Max, 120 nS Min. pulse
width
External Clock (input #2)
TTLTRIG line P2 connector
External Trigger/Start (input)
Front Panel BNC (TTL) active low
or TTLTRG line
Gate (Delayed Gate) (output)
Front Panel BNC (TTL) or TTLTRG
line. Active low during waveform
generation. Programmable delay
20 s to 41.94 sec. relative to Ext.
Trigger/Start
Precision Clock (output)
TTLTRIG line P2 connector
Clock Accuracy
16 MHz 0.005%
DSP PROCESSOR
TMS320C30 @ 33 MHz
FRONT PANEL INDICATOR
Self-Test Pass/Fail
Green/Red LED
POWER REQUIRED
+5V Supply
+4.75V Min., +5.25V Max.
Power Consumption
20W maximum
ENVIRONMENTAL AND
MECHANICAL
Rated Performance
0C to 50C
Storage
25C to +75C
Relative Humidity
0 to 85% noncondensing up to
+40C
Cooling
1.4 litre/sec. airflow for 10C rise at
0.39 mm H
2
O back pressure
Dimensions
"C" size VXI
Weight
3 lbs, 4 oz/1.47 kg
NOTES:
1. Unless otherwise noted, all specifi-
cations apply at 25C.
2. Peak Distortion -- peak distortion
represents the ratio between the
highest spurious frequency below
the Nyquist rate and the signal.
3. Total Harmonic Distortion -- total
harmonic distortion represents the
ratio between the RMS sum of all
harmonics up to 20th harmonic and
the RMS value of the signal.
Specifications subject to change with-
out notice.
DBS 8750
Specifications
1
Ordering Guide
DBS 8750
Waveform Synthesizer
SCPI Programmable
Equation
Waveform
SCPI Expression
(A sin
1t) (B sin
2t)
CALculate:MATH FOR T A SIN(
1t) B SIN(
2t)
*
*
*
a
0
(A+betcos
t) +
a
(A+betcos
t)
b
CALculate:MATH FOR T1 A+b e^(t) COS(
t) FOR T2 A+b e^(t) COS(
t)
*
*
*
*
A sin (
(t x)) / (
(t x))
CALculate:MATH FOR T1 A SIN(
(tx))/(
(tx))
*
*
*
Printed in U.S.A.
1997 ANALOGIC Corporation
Bulletin No. 16-100546 REV 1 3/97 2.5M
Analogic Corporation
Measurement and Control Division
8 Centennial Drive
Peabody, MA 01960-7987, USA
Tel: (508) 977-3000
Fax: (508) 977-6814
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