Aeroflex CS9000 Broadband Signal System Brings True Modularity to Advanced Testing
By Mark Prichard, Aeroflex

The CS9000 Broadband Signal System, BSS, is the latest in the development of Aeroflex advanced testing and mission instruments. The CS9000 grew out of the continued deployment of the Broadband Signal Analyzer, BSA, and the Broadband Signal Generator, BSG, and takes advanced testing to fully modular capabilities. The modularity of the CS9000 not only includes hardware channelization, but also packaging, testing software, mission applications and firmware.

Supporting complex systems operations, including simultaneous full bandwidth playback and monitoring/recording, the CS9000 supports development, testing and mission operations. The areas of deployment include advanced radio, RADAR, electronic warfare, intelligence and space applications. The CS9000 multiple channel capability can also be used in EME and EMI operations.

The CS9000 BSS is developed around the concept of connection of an Analog to Digital Converter, ADC, or Digital to Analog Converter, DAC, directly to an extremely large recording/playback data buffer. Because the CS9000 is fully modular, each input and output channel retains its own operational hardware and controls. The concept of operation for the CS9000 BSS is most readily thought of as a controller connected to modular channels. Each channel has been developed as a stand-alone device complete with all components, from RF input to data converters to the direct coupled memory buffer. The modularity of the channels on the CS9000 BSS also allows for integration of both BSA and BSG channels into a fully integrated instrument.

Although the CS9000 BSS is designed to support complex operations all the way to the lowest level of signal parameterization, the operator interaction is through an easily operated Graphical User Interface, GUI. The GUI has many levels of operation, from “Engineering” level where all functions, hardware and software of the instrument are available, to the “Operator” interface to facilitate ease of use and minimize operational interaction while still providing access to results that are deemed most important.

Control of the BSS system is accomplished through a Graphical User Interface. Each channel has its own controls for independent operation either through the GUI or over TCP/IP messaging over 1000 baseT Ethernet™.

Hardware Performance
The CS9000 BSS system’s input BSA and output BSG channels are designed to operate in two configuration bandwidths (narrow and wide), and in two ranges of RF tuning (low and high). The wideband channels for the BSA and BSG have a maximum bandwidth of 472 MHz (3dB) and the narrow-band channels have a maximum bandwidth of 72 MHz (3 dB). The narrowband channels also support digital and tunable down/up conversion of the signals for reduced bandwidth operations. Input and output RF tuning operational range of the high band channels are from 2 MHz to 18 GHz with 4 Hz resolution. The low band channels are fully tunable from 2 MHz to 6 GHz with a resolution of 1 Hz. The input RF converters are multiple stage construction with IF filtering to remove out of band signals before the data stream is sampled by the ADC. The output RF converters are also multistage, which utilizes a reconstruction IF filter to flatten the RF output.

Data Recording and Analysis
As stated above, the CS9000 configured with BSA channels allows the user to directly sample the RF space through downconverters and ADCs and streams this into a high-speed data buffer. This data buffer has a capacity of 32 Gigabytes per channel. In narrow band mode, this 32 GB buffer supports record operations of up to 100 (72 MHz BW) seconds of data. These record times can be extended, by powers of two, up to more than 5 hours (0.328 MHz BW), of recording time by utilization of the integrated digital down converters. In wideband mode (472 MHz BW) the 32 GB buffer supports record operations of 28 seconds.

The CS9000 BSS is designed to provide the highest dynamic range of input available in supporting the above listed bandwidths. The narrowband channels utilize 14-bit ADC and DACs giving over 68 dBc of dynamic range. In wideband mode the input channel utilizes a 10 bit ADC that is masked to 8-bit. For wideband output, the CS9000’s BSG channels use 14-bit technology. The high dynamic range of this DAC allows for data generation from playback of recordings without degradation from the digital conversion and minimal distortion for the RF upconversion.

Because the RF input is downconverted to an IF frequency, then directly sampled by the ADC, and then streamed into the high-speed memory buffer, all inputs can be considered as data streams. The data streams can have very complex analysis operations performed upon them. These data operations are performed on the time domain data streams to increase the dynamic range of the system to over 120 dBc on appropriate signals while in narrowband mode. In wideband mode the dynamic range of signal detection is around 80 dBc.

Software
The CS9000 BSS implements a GUI for data analysis and hardware control. As stated above, the GUI can be used at the engineering level for full control, or the operations level for support of specific applications.

The CS9000 also supports remote control of the system in a server-client configuration for all hardware operations through TCP/IP messaging. A published API, included with the remote control application and libraries, is available for the system. Example programs are included in the remote control package.

Analysis
The input data streams for the system, along with hardware control, analysis and visualization, are brought to the user via the Signal Safari™ interface. This GUI allows the user to quickly set up the instrument to the most appropriate mode of operation, verify the signal collection integrity, analyze the signal of interest (SOI), and then provide data storage.

Advanced tools allow the user to analyze complex signals, including their surrounding RF environment, with time domain dependence. The capability of the analysis suite to isolate a single SOI from the surrounding environment, both in time and frequency, allows the user to apply different software tools to completely understand the collected signals. With complete control of the time domain, RF center frequency, and bandwidth settings on the real-time data stream, advanced signal analysis in other dimensions can also be accomplished. Full coherent analysis of digital and analog demodulation domains is supported by the CS9000’s access to the full memory buffers of the collected signals.

Each BSA channel can also support sequencing operations. The user defines the method of collection in time, frequency, power and triggering, and the system will operate in an automatic mode. This includes each recording being saved into high-speed memory or stored to the disk drive at the end of recording.

Data Generation
The CS9000, when integrated with BSG channels, allows for the user to generate data streams of not only the signals of interest but also the full RF environment. With multiple channel systems, expansion is accomplished by adding channels to the PCIe bus to extend the bandwidth of the system. Extremely complex and complete environment structures can then be generated. Because each channel can have up to 32 GB of signal buffer, time domain dependent signals can be easily generated to meet the most demanding testing requirements.
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The application for data creation is accomplished by using the Vector Signal Simulator (VSS) GUI. This application package allows for mixing of multiple types of signals into a single data stream. The wide bandwidth of the generation channel, as well as the full control of center frequency and bandwidth, allows very complex data structures to be created. The VSS interface allows the user to control all aspects of the signal to be created. Supported data types include Analog (AM, FM, PM), Digital (ASK, FSK, nPSK, nQAM) and advanced RADAR and agile radio signals as well. Users can also incorporate recordings from BSA channels or other recording devices into the data structures created by the VSS portfolio of signals.

For playback of signals, the CS9000 uses the Vector Signal Player (VSP) application GUI. This interface allows the user to select files for playback, whether VSS created or recordings. User has control of power, frequency, playback time and start triggering to support advanced test requirements.

Each of the CS9000 BSG channels also supports sequencing. Sequencing allows the user to define a playback structure that the BSG channel will then output. This powerful method of operation can be used to create extremely complex data structures that can be changed within a single clock cycle. In a wideband BSG channel, this means that 472 MHz of bandwidth signal can be changed in 833 picoseconds. In narrowband mode (72 MHz), this structure can be changed in 4.8 nanoseconds.

Data Structure
One of the major advantages of the CS9000 is that data, both input and output, operations are conducted on real data streams. The use of a single ADC or DAC in each channel eliminates the IQ imbalance that is a limitation of most collection and playback systems. The use of a single converter in all operations ensures that the data structures contain only the signals of interest and not IQ components that contaminate the input and/or output data.

The CS9000 data format is stored in Big Endian binary as an open format. Recorded data files from the CS9000 can be read by third party programs such as MatLab™.

General Features
The CS9000 BSS system is a modular and configurable instrument. The inclusion of BSA and BSG channels is a simple process of adding components to the PCIe bus. Systems can be reconfigured as needed. Since the controller for the CS9000 requires only a PCIe bus interface, this component of the system can be easily upgraded to incorporate the latest technology in controllers to meet future needs.

The form, fit and function of the CS9000 is determined by the user’s requirements. The CS9000 technology can be constructed as standard rack mount equipment or configured for mobile operations for deployment.

All configurations are essentially a controller connected to a selection of input and/or output channels. For form factor choices, users have a selection of controllers (19" rack mount, laptop, etc.), bandwidths (narrow (72 MHz) or wide (472 MHz)), and RF range (6 GHz or 18 GHz.)
Power requirements for the CS9000 are 120/240 VAC for rack mount or 9-32 VDC for mobile applications. The amount of current required is dependent upon the number of channels.
RF input and output is usually through the front panel connectors, but other configurations are supported.

Mass storage on the CS9000 systems is accessible and removable through the front panel. If the disk drives are removed, there is no internal mass storage in the system. Volatility statements for moving systems in and out of classified areas are available.

For reduction of system downtime, the CS9000 supports many methods of system recovery, from spare operating system drives to bring the applications back to factory settings, to disaster recovery DVDs and applications. For most hardware support, a channel can be removed from the system and brought back to operational status at the factory. Critical spare lists are available as well.

The CS9000 BSS is an advanced signal conformance instrument and can be calibrated to NIST traceability, depending upon customer requirements.

Aeroflex
www.aeroflex.com
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