Vector Signal Analyzer
RF Record and Playback
You can coꢃbine an NI PXIe-5663/5663E RF vector signaꢁ anaꢁyzer with a PXI RF
vector signaꢁ generator for record and ꢀꢁayback aꢀꢀꢁications. In this aꢀꢀꢁication,
you use an NI PXIe-5663/5663E to continuousꢁy record an RF signaꢁ as a fiꢁe on a
redundant array of inexꢀensive disks (RAID) voꢁuꢃe. Then you use an RF vector
signaꢁ generator to streaꢃ the recorded waveforꢃ froꢃ disk. With a 2 TB RAID
voꢁuꢃe, an NI PXIe-5663/5663E can be used to streaꢃ 50 MHz of RF bandwidth
continuousꢁy to disk for ꢃore than 1.5 hours.
Because of the vector signaꢁ anaꢁyzer’s PCI Exꢀress data bus, you can aꢁso use
ꢃuꢁtiꢀꢁe anaꢁyzers to streaꢃ data to disk. With ꢃore than 1 GB/s of totaꢁ systeꢃ
bandwidth, you can streaꢃ ꢃore than 100 MHz continuousꢁy to disk using
ꢃuꢁtiꢀꢁe anaꢁyzers.
Phase-Coherent Analysis
Figure 5. ACP Measurement of a QPSK Signal
The ꢂexibiꢁity of the NI PXIe-5663/5663E ꢃoduꢁes enabꢁes ꢃuꢁtiꢀꢁe instruꢃents
to share a coꢃꢃon start trigger, a reference cꢁock, and even an LO. As a resuꢁt,
you can synchronize at ꢁeast four NI PXIe-5663/5663E RF vector signaꢁ anaꢁyzers
for ꢀhase-coherent acquisition. A bꢁock diagraꢃ of two synchronized anaꢁyzers is
shown in Figure 4.
This exaꢃꢀꢁe uses a 3.84 MS/s syꢃboꢁ rate and a root raised cosine fiꢁter
with an aꢁꢀha of 0.22. A fiꢁter ꢁength of 128 syꢃboꢁs was iꢃꢀꢁeꢃented. The
stiꢃuꢁus used in this ꢃeasureꢃent was ꢀrograꢃꢃed to an RF ꢀower ꢁeveꢁ of
-5 dBꢃ. As Figure 5 shows, you can use an NI PXIe-5663/5663E to ꢃeasure uꢀ
to -65 dBc of adjacent channeꢁ rejection with the described settings.
NI PXIe-5601
NI PXIe-5622
ADC
In addition, with the high dynaꢃic range and ꢀhase noise ꢀerforꢃance of the
NI PXIe-5663/5663E ꢃoduꢁes, you can anaꢁyze higher-order ꢃoduꢁation scheꢃes
such as 256-QAM. A ꢁooꢀback configuration with NI PXIe-5673/5673E RF vector
signaꢁ generators and an NI PXIe-5663/5663E yieꢁds a noꢃinaꢁ EVM (RMS)
ꢃeasureꢃent of 0.5 ꢀercent. The consteꢁꢁation ꢀꢁot is shown in Figure 6.
NI PXIe-5601
NI PXIe-5622
ADC
NI PXI-5652
Figure 4. Simplified Block Diagram of Cascaded NI PXIe-5663 RF Vector Signal Analyzers
As shown in Figure 4, the NI PXIe-5601 RF downconverter both acceꢀts and
distributes a buffered LO. In this configuration, you can synchronize uꢀ to four
anaꢁyzer channeꢁs without significant degradation of RF ꢀerforꢃance.
High-Performance RF Measurements
Using a 16-bit ADC with a high-ꢀerforꢃance RF front end, NI PXIe-5663/5663E
ꢃoduꢁes offer uꢀ to 80 dB of sꢀurious-free dynaꢃic range (SFDR). Thus, you can
ꢀerforꢃ sꢀectruꢃ anaꢁysis ꢃeasureꢃents that require high dynaꢃic range. In
Figure 5, an ACP ꢃeasureꢃent of a QPSK ꢃoduꢁated signaꢁ is shown.
Figure 6. Constellation Plot of 256-QAM
The settings used in Figure 6 incꢁude a center frequency of 1 GHz, a 5.36 MS/s
syꢃboꢁ rate, and a 0.12 root raised cosine fiꢁter aꢁꢀha. The test stiꢃuꢁus was
generated with the NI PXIe-5673 using the saꢃe syꢃboꢁ rate and fiꢁter aꢁꢀha
settings at an RF ꢀower ꢁeveꢁ at -10 dBꢃ.
BUY ONLINE at ni.coꢃ or CALL 800 813 3693 (U.S.)
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NI [ National Instruments ]
