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Signal Generation & Analysis for W-i-d-e-b-a-n-d Aerospace/Defense Systems Choosing the right broadband measurement solution for your application

The ever evolving need for improved radar resolution, high data rate of the unique test instrumentation communications, and robust interference immune reception is the driv- that is available to address the spe- ing force behind the increase in wide bandwidth signals used in modern cial needs of advanced aerospace/ Electronic Warfare (EW), MILitary COMmunications (MILCOMS), ELec- defense applications. tronic INTelligence (ELINT), and Direction Finding (DF) systems. New Architectures to Meet Finding instrumentation to and with the current state-of-the-art, the Challenge test these ever evolving wideband the wideband signal being generated Historically, these wideband test aerospace/defense systems can be a or analyzed may be in a digital form signal demands have required complex, challenge. Many of these advanced rather than an analog form. As signal custom-built test instrumentation. wideband systems are coherent multi- bandwidth exceeds 200 MHz, ﬁnding Agilent now offers test equipment channel designs, employing phased effective test equipment solutions for architectures with the features and array antennas that require multi-port today’s advanced RF system becomes interconnection ports needed to enable test capability. Both wideband signal increasingly difﬁcult. advanced wideband multi-port micro- generation and analysis are needed, In this article, we look at some wave signal generation and analysis.

Phased array Arbitrary Base-band I-Q modulation Performance waveform RF Out #N signal generator generator

Arbitrary Base-band I-Q modulation 10MHz waveform Performance RF Out #2 ref. generator signal generator (N8241A) (E8267D) Distribution amplifier (Z5623AK08) Sync. Clock trigger Arbitrary Performance RF Out #1 waveform Base-band I-Q modulation signal generator MXI-4 generator (E8267D) (N8241A) LAN

Phase coherent RF Out #1 Personal computer RF Out #2 Phase ajustable

Figure 1: The Z2090B system can produce multiple modulated signal outputs that are phase coherent with precisely synchronized modulation patterns. This allows simulation of the spatial relationships of an arriving wave-front arriving at multiple antennas.

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To illustrate, let’s explore some of the speciﬁc test and analysis solutions Base-band I-Q beginning with signal generation. Arbitrary modulation 10MHz Performance waveform RF Out #2 ref. signal Wideband Signal Source Solutions generator generator N8241A Agilent’s Z2090B wideband signal ( ) (E8267D) source solution utilizes the low phase noise E8267D Performance Signal Generator (PSG) and the high-resolu- Sync. Clock tion N8241A arbitrary waveform trigger Performance generator. The unique N8241A leads Arbitrary Base-band I-Q signal RF Out #1 the industry with an amazing 15 bits waveform modulation MXI-4 generator of amplitude resolution at sample generator (E8267D) rates of 1.25 GS/s. (N8241A)

Working together, the 44 GHz PSG LAN and high dynamic range N8241A arbitrary waveform generator deliver superb performance for a number of Personal difficult wideband applications. computer Phased Array & DF Testing Agile phased array antennas Figure 2: To generate entire spectral environments multiple N8241A arbitrary dominate new designs, many of which waveform generators can be up-converted to different frequency bands with the operate over wide bandwidths. Test- E8276D performance signal generators. ing the agile array’s ability to track a target hundreds of miles away often challenges of Phased Arrays and DF ing of modulated waveforms. requires a challenging test stimulus equipment. Architectural intercon- Phase offsets between multiple that is precisely phased across mul- nections have been provided to allow phase coherent signals from the 44 tiple channels to simulate an arriving multiple PSGs to be modulated with GHz E8267Ds are implemented using wave-front. multiple N8241A arbitrary waveform digitally synthesized modulation. This Similarly, some intelligence receiv- generators. The modulated outputs allows synthesis of complex signals ers use multiple phase coherent receiv- of the PSGs can then be connected to arriving at antenna ports with the ers to determine the bearing angle to a phase coherent array. This arrange- proper delays to simulate an arriving the signal emitter. ment can synthesize signal band- wave front. Testing these systems is difficult. widths up to 1 GHz from flexible Their wideband designs require pre- digital files defined in Agilent’s Signal Broadband EW Spectral Environments Bandwidth requirements for mili- As signal bandwidth exceeds 200 tary communications have also grown MHz, finding effective test equipment solutions over the years as systems move from for today’s advanced RF system becomes in- voice to bandwidth hungry high-resolution video. creasingly difficult. Aerospace/defense systems typi- cally function in complex RF spectral cisely phased signal inputs at multiple Studio modulation synthesis tool. environments, with jammers and input ports to simulate the spatial The Agilent Z5623A distribu- interferers that utilize many octaves of relationships of various emitters. tion amplifier, along with a common bandwidth. Compounding the growth Field-testing multi-port electronic 10 MHz reference locks the signal in data rate, many communications systems is often cost prohibitive as generators together to create a totally systems have gone to spread spectrum well, requiring expensive configura- phase coherent set of signal outputs. signals that frequency hop over huge tions of multiple airborne or surface The system further enables full bandwidths to reduce the probability assets spaced hundreds of miles apart. control over time, phase, ampli- of intercept and improve performance Responding to this demand, the tude and frequency. Synchronizing in messy signal environments. Agilent Z2090B system architecture the arbitrary waveform generator Generating gigahertz of spectral is uniquely capable of addressing the clocks together, allows precise tim- environment to test the robustness of

TECHNOLOGY LEADER SERIES these data links can require extreme ity, coherency and the like, all present made. These unique capabilities are bandwidth capability. measurement challenges. ideal for comparing the phase differ- When confronted with the need For this reason, Agilent offers a ences between two different wideband to generate such a test environ- variety of signal analysis options for receiver channels. ment, multiple PSGs modulated with broadband system analysis and test. The VSA 90000A's unique wide- N8241A arbitrary waveform gen- band two-port measurement capabil- erators can be offset in frequency to Coherent Receiver Array ity makes it an effective measurement provide continuous signal bandwidths Measurements solution for advanced wideband greater than the 1 GHz available with Whether comparing the phase of multi-channel systems. a single PSG and N8241A system. arrival of two complex modulations For example, five PSGs and to resolve a bearing angle or charac- Software Defined Radios N8241As can generate up to 5 GHz terizing the spectral shape of an Ultra When considering broadband of spectrum to test a broad range of Wide Band (UWB) signal, the Infini- signal measurement capability, spectral situations. ium Oscilloscope offers a tremendous logic analyzers may not immedi- Furthermore, the N8241A's su- variety of wideband measurements. ately come to mind; however, with perior sequencing ability allows it to Agilent’s Infiniium 90000A series the ubiquitous trend to implement create complex signals using sequenc- oscilloscopes sample at rates up to 40 greater portions of complex systems ing of short repetitive signal snippets GS/s, providing analysis bandwidths in software defined hardware with without massive amounts of signal up to 13 GHz wide. Furthermore, ultra fast FPGA digital processing, memory. This important feature enables long or continuous play of wide bandwidth spectral environments, Field-testing multi-port electronic sys- without Tera bytes of high-speed tems is often cost prohibitive as well, requiring waveform storage memory. expensive configurations of multiple airborne or In addition, the N8241A incor- porates a built-in Direct Digital surface assets spaced hundreds of miles apart. Synthesis (DDS) feature that expands simulation capabilities without using the 90000A has the industry’s lowest increasingly the wideband signal is additional memory. noise floor, best phase noise per- digital rather than analog. The Z2090B can also be config- formance and the flattest frequency The Agilent analysis product line is ured to playback wideband signal response. unique in that the 89600A VSA soft- recordings taken from the field. These superior performance traits ware is available on a variety of hard- MILCOM engineers can employ the allow the multi-channel Infiniium ware platforms. Spectrum analyzers, Z2090B to analyze system responses oscilloscope to capture ultra narrow oscilloscopes and logic analyzers can to multi-path, interference and more, time domain events and conduct RF all host this powerful analysis tool. using either recorded or synthesized modulation analysis. The Agilent 16800 series logic ana- signals. The ‘VSA 90000A Ultra Wideband lyzers, for example, support measure- Advanced tools, like Signal Studio Signal Analyzer,’ bundles the Infi- ment of wideband modulations in or third party software solutions, can niium 90000A oscilloscope with the digital formats with the 89600A VSA quickly and easily generate complex 89600A Vector Signal Analyzer (VSA) software. multi-carrier spectral environments software. This powerful combination Not only do these high speed wide that include moving emitters with expands the Infiniium’s measurement bandwidth logic analyzers provide changing Doppler shifts. capability far beyond traditional time a means to measure digital signal The Agilent Z2090B series signal domain measurements. The VSA modulation performance while still in simulation systems offer the flexibil- software enables frequency domain a binary bus format, but the 89600A ity and performance for addressing spectral measurements as well as in software interface is identical to that challenging wideband signal stimulus depth modulation measurements. used on Infiniium oscilloscopes and requirements. In addition to performing these traditional vector signal analyzer measurements on signals with many instruments. Broadband Signal gigahertz of bandwidth, the multiple The 89600A analysis software Analysis Options input ports of the high-speed oscil- can then be applied to vastly differ- Many of the same challenges that loscope allow simultaneous two-chan- ent signal formats. Logic analyzers exist for creating test signals exist for nel analysis. can perform modulation analysis analyzing broadband modulated sig- Even cross channel signal correla- on digital I–Q busses. Even bus nals: bandwidth, multi-port capabil- tions and phase measurements can be signals deep inside Field Program-

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Inﬁniium Oscilloscope

16800 Logic Analyzer

Inﬁniium Oscilloscope PSA Spectrum Analyzer + Opt 123

IIQ Q I Q MS8 DAC IF RF Data LS8 FPGA Clock MS8 DAC LS8

Figure 3: Agilent offers a unique set of wide bandwidth analysis tools that all use the powerful 89600A vector signal analyzer software. High-speed logic analyzers, broadband oscilloscopes and high performance spectrum analyzers allow consistent detailed modulation analysis, no matter what signal format is used. mable Gate Arrays (FPGA) can to achieve measurement bandwidths Whether the requirements are for be probed with Agilent’s FPGA up to 230 MHz throughout the PSA’s radar, EW, ELINT, phased arrays, or dynamic probing. frequency range of 3 Hz to 50 GHz. just terrestrial Ultra Wide Band (UWB) The view scope function coordi- Other external down-converters can communications, the Z2090B provides nates precision timing of the logic be used for wider bandwidths. In addi- a test stimulus platform for wideband Product speciﬁ analyzer and oscilloscope signals on tion to the broad frequency range and success. a single screen, to reveal the exact high bandwidth of these instruments, The advanced measurement capa-

digital bus state of signal errors found the 89600A VSA software provides bilities of Agilent’s 89600A VSA soft- cations and descriptions in this document subject to change without notice. with the 89600A VSA software. error corrected data with its new down- ware and variety of hardware front ends The MXA or E4440 PSA series converter calibration algorithms. These ranging from the E4440 PSA, Infiniium of Performance Spectrum Analyzers routines remove I and Q gain, offset, oscilloscopes to the 16800 series logic (PSA) also support the same 89600A and quadrature errors introduced by analyzers, can tackle tough wideband, software, allowing uniform analysis the down-converter interface. This coherent multi-port analysis problems. of all types of signal formats at vastly unique combination of high-perform- Agilent would like to help. Sup- different frequencies and with vastly ance hardware and software provides a ported by factory experts, the Agilent different signal formats. Now, one powerful measurement tool for broad- field representative is trained to assist consistent set of analysis software band MILCOM signals as well as char- you in electing the right broadband can compare modulated signals acterization of radar pulses containing stimulus and analysis test solutions across digital and analog format complex intra-pulse modulation. for demanding aerospace and defense transitions. applications. For wideband analysis the PSA Outlook spectrum analyzer with option 123 Agilent offers the wideband mea- FOR MORE INFORMATION can function as a broadband down- surement solutions needed to extend Visit www.agilent.com/find/wideband converter whose IF output can be dig- performance far beyond typical test or call 1-800-829-4444 to speak with itized using the Infiniium oscilloscope instruments. your Agilent sales representative.