Data interpolation with SBench 6 software.

Spectrum Instrumentation adds new functionalities to SBench 6 software

  • Spectrum Instrumentation adds customization, automation, processing, and interpolation capabilities to its SBench 6 software to control its digitizers, arbitrary waveform generators, and other digital I/O boards and modules.
  • This software manages the process of signal acquisition, generation, display, analysis and documentation.

# Scripting allows easy automation
For users who want to utilize SBench6 in an automated sequence of operations, a scripting tool is now available. Scripting allows basic commands to be arranged via a plain ASCII file that is called by the SBench 6 program. For example, SBench 6 can be instructed to load specific configurations, start and stop acquisitions, wait or loop, export data and even call external programs.

Scripting with SBench 6 software
Example of a small ASCII script file that asks SBench 6 to make ten acquisitions each minute and export the data produced directly to Matlab.

# Data interpolation
Another addition to the SBench 6-Professional software is data interpolation. This feature can be used to improve parameter measurements in situations where the sampling rate of a digitizer is limiting measurement precision. Based on the SinX/x (or sometimes called SinX) algorithm, the SBench 6 interpolation function inserts samples in a predictive manner between the actual acquired data points. When done correctly, this produces a waveform with a higher effective sampling rate and a closer approximation to the analogue waveform that is being analyzed.

Data interpolation with SBench 6 software.
Interpolation can significantly improve parameter measurement accuracy and precision.

The benefit of interpolation becomes apparent as the input signal frequency begins to approach the Nyquist limit (half the sampling rate). Consider above figure. Here a 20 MHz sine wave with 1.82 V amplitude is acquired by a digitizer sampling at 125 MS/s and with 16-bit resolution. The yellow trace on the left shows the signal without interpolation and with the sample points connected by linear lines. The blue trace on the right is the same signal but with interpolation activated. Both traces have been expanded vertically so you can examine the top of the sine wave.

Note that the 20 MHz signal is still well below the Nyquist limit of 62.5 MHz. However, the yellow trace (without interpolation) already has an insufficient sampling rate to precisely measure the signal’s amplitude. The problem is that, at 125 MS/s, each cycle of the sine wave only contains around six sample points. Activating the interpolation function effectively improves the sampling rate. In this example, an interpolation factor of 10 was selected, creating a trace with 60 samples per cycle. Parameter measurements for the Peak-to-Peak amplitude (lower left corner) made for both traces show the significant improvement in amplitude accuracy that is possible.
Providing the frequency content of the input signal does not exceed the Nyquist limit, interpolation can be also be used to improve other parameter measurements (such as rise and fall times, as well as cyclic measurements like frequency and period).

# Customized Calculations
SBench 6-Professional has an extensive array of data processing tools (e.g. FFT analysis, math functions, filtering, averaging, parameter measurements, etc.) that can now be complimented by a new plug-in option which enables users to create their own customized calculations as a self-compiled plug-in that is automatically linked into the SBench 6 calculation pool. The plug-in option includes an SDK as well as a number of examples based on the C++ programming language. It allows programmers to develop their own plug-ins by combining advanced calculations on the acquired signals. Any calculation that can be realized with standard development methods is possible. Furthermore, any files in the system (such as filter parameters, sensor calibration values or reference signals) can be utilized in the calculation. The SDK also provides a call-back function for interaction with the user so that simple dialogs and other information, such as cautions or critical warnings, can then be flagged to the user.

Plug-in for SBench 6 software
A Plug-in example for signal inversion with customized data storage.

The plug-in option allows users to integrate their own processing functions directly into the SBench 6 program. Resulting signals can be displayed, used for further calculations, exported or can be part of a report. For example, when using a digitizer together with sensors, the plug-in could embed specific sensor calibration information into the program. Above figure shows a typical plug-in example where signals are inverted and stored. Note that programmer can define the calculation configuration using integer or double values, combo boxes, strings or checkboxes. Once the routines are developed, the resulting plug-in files can be freely distributed with any SBench 6 Professional license to end-users.

# Calculate Single Values
It is now also possible for the new Formula function to calculate single values. These values can be computed from the cursor information, any sample of a source signal or even from other calculation results.

Adding to the processing flexibility, “single values” can even be accessed and incorporated into a formula when creating new waveforms with the program’s Function Generator feature. The result is a waveform creation tool that lets you make waveforms using recorded or loaded signals.

# Detect out-of-range signals with Input Channel Preview
An Input Channel Preview window has been added to SBench 6-Professional. The window works by continuously monitoring the input signals at a low sampling rate and then displaying their key signal characteristics using a bar graph. The Input Channel Preview window reveals, for each active channel, the signal’s current minimum, maximum and average value. Color coding (green, red and yellow) then highlights when signals are in and out of range or when an input range has changed status. Users are instantly alerted to each channel’s condition, making it immediately obvious when changes to the setting of their gain or offset may be required.

# Free for all SBench6-Professional Users
With the exception of the Plug-in tool for customized calculations, which is an option, users of SBench 6-Professional can access the new capabilities (Scripting, Single Value Formula, Input Channel Preview and Interpolation) for free. The functions, along with other recent additions to the program, such as FFT based Power Spectrum Density measurements, can be obtained by downloading the latest version of the software from the Spectrum Instrumentation website. A free trial version of SBench 6-Professional is also available.