Measurement Computing PCI-DAS4020/12 - Manual (Page 24)

PCI-DAS4020/12 User's Guide Specifications
24
Dynamics and noise
Table 6. Dynamics and noise specifications
SNR (Signal-to-noise ratio) 66.6 dB
SINAD (signal-to-noise and distortion ratio) 66.5 dB
SFDR (spurious free dynamic range) 80 dB
THD (total harmonic distortion) 80 dB
Noise distribution:
(Rate = 10 KHz-20 MHz, Average % ± 2 bins,
Average % ± 1 bin, Average # bins) Bipolar (5V): 100% / 98% / 5 bins
Bipolar (1V): 100% / 98% / 5 bins
Trig/Ext Clk BNC
Software selectable for A/D Start Trigger (TRIG1), A/D Stop Trigger (TRIG2) or A/D Pacer Gate (AGATE);
also used as an A/D clock input 2X clock source (DAQ_CLK).
Table 7. Trig/Ext Clk BNC specifications
Input impedance 50 ohm, 1 Mohm selectable (coaxial cable termination)
Input threshold Programmable 2.5 V threshold or 0 V threshold
Input slew rate 1 V/µsec min
Input range ±5 V
Bandwidth 40 MHz
Coupling DC
Analog output
Table 8. Analog output specifications
D/A converter type AD7237
Resolution 12-bits
Number of channels 2
Output range ±10 V, ±5 V software selectable
D/A pacing Software paced
Throughput System dependent. Using the Universal Library programmed output function (cbAout) in a
loop in Visual Basic, a typical update rate of 500 Hz (± 50 Hz) can be expected. The rate
was measured on a 330 MHz Pentium II based PC.
Data transfer Programmed I/O
Monotonicity Guaranteed monotonic over temperature
Analog output drift ±0.11 LSB/°C max, all ranges
Settling time
(20 V step to ± ½ LSB) 5 µs max
Slew rate 5 V/µs
Current drive ±5 mA
Output short-circuit
duration 25 mA indefinite
Output coupling DC
Output impedance 0.5 Ohm max
Miscellaneous
 Single buffered output latch
 Update DACs individually
On power-up and reset, the inputs to both D/A output buffers are grounded and the board’s
D/A outputs will be set to 0 volts ± 6 mV. Upon writing to the D/A converters, the output
buffers will reflect the D/A outputs and achieve rated accuracy. However, upon writing a 0
to the D/A’s, a small output change may be noted (up to 10 LSB).