Chapter 2
NI 5450 Overview
©
National Instruments Corporation
2-27
NI PXIe-5450 User Manual
Filtering and Interpolation
The filtering and interpolation stage of the OSP block increases the
effective sample rate of the signal generator while protecting the frequency
spectrum of the interpolated data from images. This protection occurs when
the data passes through a lowpass filter after zero stuffing. The frequency
response of the low pass filter can be changed with the Filter Type property
or the
NIFGEN_ATTR_OSP_FIR_FILTER_TYPE
attribute.
Writing I/Q Data
On multichannel devices, I/Q data can either be written to individual
channels (for example, designating one channel for I data and one channel
for Q data) or to both channels of the device at once when following the
multichannel waveform allocation guidelines.
Basic Onboard Signal Processing Properties
The following properties must be configured before you can use the OSP
block:
•
OSP Mode
•
OSP Enabled
•
Data Processing Mode
•
IQ Rate
•
Frequency Shift
•
FIR Filter Type
OSP Mode
The OSP Mode property or the
NIFGEN_ATTR_OSP_MODE
attribute
specifies the generation mode implemented by the OSP block. The OSP
block can operate in IF and Baseband modes. On the NI 5450, the default
OSP mode is Baseband generation.
Inp
u
t D
a
t
a
O
u
tp
u
t D
a
t
a
High
Sa
mple R
a
te
Low P
ass
Zero
Low
Sa
mple R
a
te
S
t
u
ff
Filter
