NSI Standard Edition
Far-Field Measurement And Analysis Software

NSI-SW-5312

NSI's Far-field Measurement and Analysis Software consists of the NSI 2000 Standard Edition Software package configured for far-field applications. The NSI 2000 Software is the most advanced and comprehensive antenna measurement software available today, and is currently running on a large number of installed antenna measurement systems. The NSI 2000 far-field software represents a combination of experience and technology that stands ready to solve your toughest antenna measurement challenges.

The Far-field Measurement and Analysis software is capable of interfacing to positioner controllers from third party suppliers such as ACC, MI-Technologies and Orbit, allowing far-field systems to be designed or upgraded with a mix of positioner controllers from NSI and other suppliers. For far-field applications, the NSI software uses the same proven RF equipment drivers and multi-beam control software that is used in all of NSI's antenna measurement systems.

The NSI 2000 Far-field software is capable of calibrated gain measurements, and post-measurement antenna pattern analysis, including beamwidth and side lobes levels. The NSI 2000 Professional Edition Far-field Software includes the popular NSI Scripting capability, which allows the user to automate many of the NSI 2000 measurement and processing functions. The scripting capability may also be used to interface existing acquisition or analysis software written in other languages such as Fortran, C or C++.

Some of the far-field unique capabilities of NSI 2000 are described in the following pages. Additional details on NSI 2000 Professional Edition Software may be found in the Software section of this catalog.

NSI 2000 Far-Field Features Include:

• Data collection and processing software are part of one package
• Full 32-bit Windows NT application and support for standard Windows conventions (cut and paste, right mouse click for additional option, etc)
• Data collection of multiple axes, frequency and switches in a single measurement
• Collection of arbitrary frequency, beam, and switch combinations
• Positioning control using multiple controllers
• Adjustment and control of measurement smear
• Gain calibration and pattern measurement modes
• Ability to export plot or measurement data to an ASCII file for customer analysis
• Ability to import ASCII data files for plot overlays
• Standard analysis routines included (beampeak, beamwidth, side lobes level, etc.)
• Drag and Drop plots
• Scripting Language Support (optional)
• Operator controlled plot annotation
• On-line Help

Control of Multiple Positioner Controllers

For range upgrades, NSI 2000 is designed with the capability to mix and match positioner controllers. This allows the user to define a test with positioner movement from more than one controller. For example, the operator might want to control the AUT position with an SA2012A controller and the Tx head with an Orbit AL-4806 controller. This design allows the greatest flexibility possible during the acquisition sequence. The figure below shows a configuration where NSI 2000 is controlling the roll head positioner axis with an NSI stepper motor controller and the large azimuth positioner with an SA2012A based subsystem.

Calibration and Pattern Modes

In NSI 2000 calibration mode is designed to be used for calibrated gain measurements. Calibration measurements are typically multi-frequency measurements done prior to making pattern measurements of the AUT. The calibration measurements are used to compute the difference between the measured gain standard, its gain table and the measured AUT. Pattern measurements of the AUT can be multi-beam, multi-frequency measurements. During processing, the gain will be automatically computed based on the calibration measurements for any frequency.

Post-Measurement Analysis

NSI 2000 has a set of post-measurement analysis functions that are produced as a part of the standard output. These are 3 dB BW, 6 dB BW, 10 dB BW, right and left side lobes level. In addition, the Scripter can be configured to produce plots with any level of sophistication of analysis functions. The analysis results can be easily placed back into the plot text before printing.

Scripting

The NSI 2000 Professional Edition includes a scripting capability that can be configured to incorporate any sophisticated data acquisition and analysis feature. The scripting feature is similar to VBA in Office 2000 applications and is essentially the Visual Basic programming language. With the Scripter you can create macros to perform any feature you can do through the standard NSI 2000 user interface. In addition, you can add capability to affect program flow with script commands such as For-Next loops and If-Then-Else statements. These commands can interrupt the normal sequence of operation to perform special acquisition, processing or analysis tasks.

The Scripter has a simple user interface that allows you to easily create custom scripts (shown below). A list of commands below which correspond to NSI 2000 dialog options can be placed into the program using drag-and-drop and then modified by the user. The list always contains information reflecting the current state of all menus.

Once the set of commands is in place and has been edited with the desired numbers, the user hits the play button and executes the script. Each script command is executed which in turn changes the menu options and produces the desired output plots or files. The Scripter also has access to the data itself. Arrays can be accessed which contain the measured or processed data. These can be used to get at the data directly for special processing, as desired by the user. In addition, the Scripter has the ability to execute other programs (. call DLLs made in other languages, such as Fortran or C++.