Measurement Computing USB-1616HS-2, User Manual, Page: 23 / 54

USB-1616HS-2 User's Guide Functional Details
23
Although averaging can be effective, it suffers from several drawbacks:

Noise in measurements only decreases as the square root of the number of measurements—reducing RMS
noise significantly may require many samples. Thus, averaging is suited to low-speed applications that can
provide many samples.

Only random noise is reduced or eliminated by averaging. Averaging does not reduce or eliminate periodic
signals.
Analog output
The USB-1616HS-2 has two 16-bit, 1 MHz analog output channels. Analog outputs can be updated at a
maximum rate of 1 MHz.
The channels have an output range of -10 V to +10 V. Each D/A can continuously output a waveform. In
addition, a program can asynchronously output a value to any of the D/A channels for non-waveform
applications, assuming that the D/A is not already being used in the waveform output mode.
When used to generate waveforms, you can clock the D/As in several different modes.

Internal output scan clock : The onboard programmable clock can generate updates ranging from 1 Hz to
1 MHz.

External output scan clock
: A user-supplied external output scan clock at the DPR screw terminal.

External input scan clock
: A user-supplied external input scan clock at APR can pace both the D/A and
the analog input.

Internal input scan clock : The internal ADC scan clock.
Example: Analog channel scanning of voltage inputs and streaming analog
outputs
The example shown in Figure 11 adds two DACs and a 16-bit digital pattern output to the example presented in
Figure 7 on page 19.
Figure 11. Analog channel scan of voltage inputs and streaming analog outputs example
This example updates all DACs and the 16-bits of digital I/O. These updates happen at the same time as the
output scan clock. All DACs and the 16-bits of pattern digital output are updated at the beginning of each scan.