Vector Signal Generator
NI PXIe-5673, NI PXIe-5673E
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◾
85 MHz to 6.6 GHz frequency range
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◾
>100 MHz bandwidth
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Up to +10 dBm RF power
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112 dBc/Hz phase noise at 10 kHz
offset at 1 GHz
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66 dBc adjacent-channel leakage ratio
for WCDMA-like signals
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<7.5 ms tuning time
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-64 dBc typical image rejection at 2.4 GHz
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-64 dBc typical carrier suppression
at 2.4 GHz
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Full bandwidth streaming
from disk (100 MS/s)
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RF List Mode support for NI PXIe-5673E
Operating System
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Windows 7/Vista/XP/2000
Included Software
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NI Modulation Toolkit
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NI-RFSG driver
Programming API
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LabVIEW Real-Time
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LabWindows
™
/CVI
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◾
C++/.NET
Overview
The NI PXIe-5673 and PXIe-5673E are wide-bandwidth 6.6 GHz RF
vector signal generators. Combined with the appropriate software, an
NI PXIe-5673/5673E can generate a variety of signals. With the NI Modulation
Toolkit for LabVIEW, it can generate different waveforms including AM, FM,
CPM, ASK, FSK, MSK, PSK, QAM (4, 16, 64, and 256), multitone signals, arbitrary
waveforms, and many others. In addition, you can combine these vector signal
generators with standard-specific software to generate signals for GPS, GSM/
EDGE/WCDMA, WLAN, WiMAX, DVB-C/H/C, ISDB-T, ZigBee, and others. With
NI PXIe-5673/5673E stream-from-disk capabilities, you can generate continuous
waveforms that are up to several terabytes in length.
As Figure 1 illustrates, the NI PXIe-5673 consists of the NI PXIe-5611 RF
upconverter, the NI PXI-5652 RF continuous wave (CW) source, and the
NI PXIe-5450 dual-channel arbitrary waveform generator (AWG). The NI PXI-5652
CW source uses a voltage-controlled oscillator (VCO) architecture, enabling
frequency tuning times no greater than 6.5 ms. In addition, the NI PXIe-5450
AWG 16-bit digital-to-analog converter (DAC) generates baseband I and Q
signals at data rates of up to 200 MS/s. At this sample rate, the generator is
capable of producing more than 100 MHz of RF bandwidth. Figure 2 shows
a QPSK signal with more than 100 MHz of bandwidth at 5.8 GHz. The signal
represented is configured for a symbol rate of 100 MS/s and a root raised cosine
filter with an alpha of 0.22.
Basic Architecture
The NI PXIe-5673 uses direct RF upconversion from differential baseband I and Q
signals. A block diagram of the system is shown in Figure 1.
NI PXIe-5450
DAC
90
˚
NI PXIe-5611
DAC
NI PXI-5652
Figure 2. QPSK Signal with Wide Bandwidth
Figure 1. Block Diagram of the NI PXIe-5673
Vector Signal Generator
Enhanced Architecture
The NI PXIe-5673E (E for enhanced) offers additional performance and features
including RF List Mode support and configurable loop bandwidth for decreased
tuning times. As with the NI PXIe-5673, the NI PXIe-5673E comprises three
modular instruments. The NI PXIe-5450 is a dual-channel AWG that provides
16-bit digital-to-analog conversion and generates baseband I and Q signals at
data rates of up to 200 MS/s. You then can use an enhanced NI PXIe-5611 RF
upconverter with an NI PXIe-565x CW source acting as the local oscillator (LO)
for direct upconversion to RF.
With the enhanced NI PXIe-5673E, you can configure a wide- or narrow-loop
bandwidth for the VCO of an NI PXIe-565x. By using a wide-loop bandwidth, you
increase tuning time at the expense of additional phase noise; if you require
lower phase noise over faster tuning times for a particular measurement, you
can specify a narrow phase-locked loop (PLL) bandwidth for best performance.
You can achieve tuning times of less than 300 µs to under 0.1 ppm of the final
frequency when using the wide-loop bandwidth configuration.
RF List Mode
The NI PXIe-5673E provides list mode support for fast and deterministic RF
configuration changes. You supply a configuration list, and the RF modules
proceed through the list without additional interaction with the host system and
driver, making the configuration changes deterministic. Figure 4 illustrates this
determinism with a single tone at 1 GHz stepping through six power levels in 7 dB
steps starting with -10 dBm and ending with -45 dBm and a 500 µs dwell time
specified for each step. Analysis was performed using the NI PXIe-5663E vector
signal analyzer.
Fast Waveform Downloads
One of the biggest advantages of PXI Express instrumentation is the benefit of
high-speed waveform transfer rates. Using an NI PXIe-5673/5673E, you can
download waveforms onto an instrument’s memory significantly faster than with
traditional instrumentation. Using a x4 PCI Express interface, you can download
waveforms to memory at speeds of up to 800 MB/s.
Figure 4. Deterministic 500 µs Power Steps Using the NI PXIe-5673E and RF List Mode
You can use the NI PXIe-5673E in both open- and closed-loop scenarios
to specify the source for the configuration trigger that advances from one
configuration to the next. In an open-loop situation, the NI PXIe-5673E advances
through the list based on a user-defined time specification for each step. The
closed-loop scenario relies on an external trigger that may be provided by the
device under test to advance through the RF configuration list.
Phase-Coherent Generation
The flexible architecture of an NI PXIe-5673/5673E enables multiple instruments
to share a common start trigger, reference clock, and even an LO. As a result, you
can synchronize up to four NI PXIe-5673/5673E RF vector signal generators for
phase-coherent signal generation. A typical configuration of two synchronized
generators is shown in Figure 3. With up to four channels of synchronized RF
signal generation, you can easily address MIMO and beamforming applications.
NI PXIe-5450
DAC
90
˚
RF Record and Playback
You can combine an NI PXIe-5673/5673E with a PXI RF vector signal analyzer for
record and playback applications. Using a 2 TB redundant array of inexpensive
disks (RAID) volume, you can continuously generate up to 100 MHz (400 MB/s)
for more than 1.5 hours. In this application, an NI PXIe-5663/5663E vector
signal analyzer records up to two hours of continuous RF signal and the data is
stored as a binary file on a RAID volume. The NI PXIe-5673/5673E then streams
recorded waveforms from disk. In addition to recorded waveforms, you can use
streaming technology to generate large simulated waveforms.
NI PXIe-5611
DAC
NI PXIe-5450
DAC
90
˚
NI PXIe-5611
High-Performance Signal Generation
Higher-order modulation schemes such as 256-QAM require strong dynamic
range and phase noise performance. Using an NI PXIe-5673/5673E, you can
generate a variety of signals with significant accuracy. As shown in Figure 5,
a loopback configuration with an NI PXIe-5673/5673E and NI PXIe-5663/5663E
yields a typical EVM (RMS) measurement of 0.5 percent (1250 symbols, software
equalization disabled).
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DAC
NI PXI-5652
Figure 3. Simplified Block Diagram of Synchronized RF Vector Signal Generators
2
Vector Signal Generator
Figure 5. Constellation Plot of 256-QAM
In Figure 5, a center frequency of 1 GHz, a symbol rate of 5.36 MS/s, and a
root raised cosine filter with 0.12 alpha was used. The RF power was set to -10 dBm
and analysis was performed with the NI PXIe-5663. In addition, the wide
bandwidth of an NI PXIe-5673/5673E combined with high-performance image
rejection enabled the generation of modulated signals at high symbol rates. For
example, Figure 5 shows a constellation plot of a 64-QAM signal at 40.99 MS/s
with an RMS EVM of 0.9 percent (1250 symbols, equalization disabled).
Figure 7. Spectrum of QPSK Signal at 1 GHz
A symbol rate of 3.84 MS/s and a root raised cosine filter with alpha 0.22 is
used. As Figure 7 illustrates, an NI PXIe-5673/5673E yields an adjacent channel
power measurement of better than -69 dBc rejection when configured with the
settings described.
Flexible Software
With NI Modulation Toolkit for LabVIEW software, you can operate an
NI PXIe-5673/5673E as a general-purpose vector signal generator. Using
NI LabVIEW or LabWindows/CVI example programs, you can generate a variety
of modulated signals.
These modules are programmed with the NI-RFSG driver, which contains
several performance-enhancing characteristics. Using an optimized driver
stack combined with fast-settling VCO-based hardware, you can tune an
NI PXIe-5673/5673E to 0.1 ppm of its settling frequency with a typical tuning
time of less than 1.5 ms. With the NI PXIe-5673E, a wide-loop bandwidth
configuration results in tuning times to within 0.1 ppm of the final frequency
in under 300 µs.
You also can use the NI-RFSG driver to enhance the RF performance. With
Figure 6. Constellation Plot of QPSK with 50 MHz of Bandwidth
an RF impairments API, you can manually or programmatically adjust I/Q
impairments such as gain imbalance, DC offset, and quadrature skew.
A LabVIEW property node that illustrates how you can adjust these parameters
on the fly is shown in Figure 8.
In Figure 6, a center frequency of 825 MHz was used. The RF power was set
to -10 dBm and analysis was performed with the NI PXIe-5663. While an EVM
of 0.9 percent is a nominal value, the typical result is 1.1 percent.
In addition, the combination of high dynamic range and a linear front end
yields high-performance adjacent channel power measurements. In Figure 7,
observe the spectrum for a QPSK signal at 1 GHz center frequency.
Figure 8. RFSG Impairments Property Node
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3
Vector Signal Generator
Typical out-of-the-box image and carrier suppression is better than -60 dBc,
but you can reduce suppression to better than -80 dBc for a particular frequency
and temperature by adjusting quadrature impairments through the RFSG VQ
impairments API. Figure 9 illustrates the carrier suppression at 1 GHz for a
10 MHz tone.
Ordering Information
NI PXIe-5673
128 MB onboard memory...............................................................780418-01
512 MB onboard memory...............................................................780418-02
NI PXIe-5673E
128 MB onboard memory...............................................................781263-01
512 MB onboard memory...............................................................781263-02
Phase Coherent VSGs
NI PXIe-5673/5673E VSG channel extension kit ...........................780485-01
NI PXIe-5673E two-channel VSG ...................................................781340-02
NI PXIe-5673E three-channel VSG .................................................781340-03
NI PXIe-5673E four-channel VSG ...................................................781340-04
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For complete product specifications, pricing, and accessory information,
call 800 813 3693 (U.S.) or go to
ni.com/pxi.
Figure 9. Use the impairments API to reduce image and carrier suppression.
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Vector Signal Generator
Specifications
Frequency
Frequency Range
85 MHz to 6.6 GHz
85 MHz to 3.3 GHz
85 MHz to 1.3 GHz
Note:
NI PXIe-5673 part numbers vary according to memory size.
NI PXIe-5673 Part Number
780418-0X
dBc
2
0
–
–
–
–
–
–
–2
780417-0X
780416-0X
–4
–6
Bandwidth
Modulation bandwidth
(3 dB double sideband)..........................
>100 MHz
The modulation bandwidth specification assumes the frequency range is between
85 MHz and 6.6 GHz. For example, 100 MHz bandwidth can be achieved at a
frequency of 135 MHz but not 85 MHz.
2
0
–2
dBc
–4
–6
–8
–10
–200
–
–150
–
–
–
–8
–10
–200
–150
Figure 3. Typical Modulation Bandwidth at 5.8 GHz Carrier Frequency
Data streaming continuous
transfer rate ......................................
500 MB/s, nominal
Tuning Resolution (NI 5650/5651/5652)
<1.3 GHz ................................................
≤1.3 to ≤3.3 GHz....................................
≤3.3 to ≤6.6 GHz....................................
<1 Hz
<2 Hz
<4 Hz
–
–100
–
–50
0
MHz
50
100
–
150
–
200
Figure 1. Typical Modulation Bandwidth at 1 GHz Carrier Frequency
In figures 1 through 5, typical modulation bandwidths show the actual baseband
response. The usable bandwidth is limited by the NI 5450 I/Q generator sample
rate from -80 to 80 MHz. The shaded area between the solid lines indicates the
frequency range covered by this specification.
2
0
–2
dBc
–4
–6
–8
–10
–200
–
–150
–
–
–
–
–
–
–
–
–
Figure 2. Typical Modulation Bandwidth at 2.4 GHz Carrier Frequency
–
–100
–100
–
–50
–50
–
0
MHz
0
MHz
50
50
–
100
100
–
150
150
–
200
200
Frequency Settling Time
0.1 x 10
-6
of final frequency...................
0.1 x 10 of final frequency...................
-6
<7.5 ms, maximum
<3.5 ms, typical
The frequency settling time specification includes only frequency settling and
excludes any residual amplitude settling that may occur as a result of large
frequency changes.
Internal Frequency Reference (NI 5650/5651/5652)
Frequency ..............................................
Initial accuracy ......................................
Temperature stability (15 to 35 ˚C) .......
Aging
Per year .............................................
±5 x 10
-6
, maximum
10 MHz
±3 x 10
-6
±1 x 10
-6
, maximum
External Reference Input (NI 5450)
Frequency ..............................................
Amplitude ..............................................
Input impedance....................................
Coupling ................................................
10 MHz
1.0 V
pk-pk
to 5.0 V
pk-pk
into 50 Ω
50 Ω
AC
External Reference Output (NI 5450)
Frequency ..............................................
Reference clock out...............................
Output impedance .................................
Coupling ................................................
10 MHz
0.7 V
pk-pk
into 50 ½, nominal
50 ½
AC
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