JYTEK USB-62405, User Manual

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Operation 31
channels. Data not retrieved in time is overwritten with new data with -
out notification. The UD-DASK Function Library Reference provides cor -
responding software API details.
Continuous Acquisition Mode
Differs from software polling mode only in the generation of block data
in continuous acquisition mode without the need to consider data over -
writing or acquiring repeat data in software polling mode. This mode is
suitable for when continuous data is to be acquired in a fixed and pre -
cise time interval. Please note the data buffer size must be a multiple of
256 in continuous acquisition mode. The UD-DASK Function Library Ref -
erence provides corresponding software API details.
3.2.5 Anti-Aliasing Filter and Frequency Response
The filter limits the bandwidth of the signal path and rejects out-of-band
noise. The digital filter of the Sigma-Delta ADC sets the overall frequency
response, using multi-stage FIR topology to provide linear phase with
minimal passband ripple and high stopband attenuation. These image
frequencies, if present in the signal and not externally filtered, will fold
back (or alias) into the passband, causing errors. The stopband of the
ADC provides 100dB attenuation of frequencies that begin just beyond
the passband and continue out to ADC over-sampling rate. The
USB-62405 provides an anti-aliasing, low-pass, simple RC filter in front of
the ADC inputs to limit possible high amplitude out-of-band signals and
noise.