Measurement Computing Data Translation DT9857, Руководство пользователя

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Chapter 5
84
Analog Output Features
This section describes the following features of analog output operations:
• Analog output channels, described below
• Output ranges and gains, described below
• Output resolution, described below
• Output clocks, described below
• Output conversion mode, described on page 85
• Output triggers, described on page 88
• Data format and transfer, described on page 89
• Error conditions, described on page 89
Analog Output Channels
DT9857 and DT9857E modules support two analog output channels (0 and 1) through analog
output subsystem 0. You can also update the digital output port in the analog output stream
by specifying channel 2 in the analog output channel list.
DT9857 and DT9857E modules provide a two-pole, 120 kHz Butterworth filter and quiet start
circuitry to prevent noise from interfering with the output signal.
The analog output channel powers up to a value of 0 V ±10 mV.
Output Range and Gain
DT9857 and DT9857E modules can output bipolar analog output signals in the range of ±10 V
using a gain of 1.
Output Resolution
The resolution of the analog output channel is fixed at 32-bits; you cannot specify the
resolution in software.
Output Clocks
The DT9857 and DT9857E modules support a 48 MHz internal clock source, which is derived
from the 24 MHz USB crystal oscillator. The same internal 48 MHz clock signal is used for the
both the analog input and analog output subsystems.
For the analog output subsystem, use software to specify the internal clock source and the
output frequency. The output frequency can range between 30 kHz and 216 kHz.