Spectral Dynamics - SigLab

General SigLab Application Questions

What application notes are available?

Here is a list of downloadable Application Notes. You can download and save each full application note simply by clicking on the title.

Can I export my SigLab data to Microsoft Excel?

After making measurements, you can instantly create a single report file (as an Excel file-.xls) that includes the key measurement parameters, the acquired data in a table, and your custom data plots. The report file is generated by an Excel Macro written in Visual Basic. The code is concise, well documented, and most importantly, all yours for you to customize.

How can SigLab help with designing and implementing controls systems?

The SigLab/MATLAB combination is ideal for the design and analysis of control systems. Almost all of SigLab's Virtual Instruments are used at various points in a typical control design scenario. SigLab's measurement results may be used directly or as inputs to the numerous MATLAB control oriented toolboxes. An advanced recursive lattice system identification package for system modeling is part of the standard SigLab application software. Also, both broad band FFT based, and traditional swept-sine, transfer function estimators are provided. The SigLab/MATLAB combination is a total solution for control system analysis whether the underlying paradigms be classical, state-space, or fuzzy.

You should also browse the Application Center for specific Application Notes and User Applications for Control.

What can SigLab do for structural analysis?

SigLab is ideal for mechanical structural analysis. Input signal conditioning may be added inside SigLab for a direct accelerometer and force transducer interface. (See Application Note: Biasing Internally Amplified Accelerometers) Multiple SigLabs may be linked together (with appropriate optional cables) creating a fully synchronized 8-16 channel system. SigLab's network analyzer is used to accurately measure the mechanical transfer functions using a shaker or a "modal hammer" to excite the structure. Force and Exponential windows are available. Measurement results drive the MATLAB based Structural Dynamics Toolbox from the Scientific Software, or by saving them in the UFF File format, they can be loaded into most commercially available modal analysis packages including ME'Scope from Vibrant Technology Inc. and SMS Star Modal from Spectral Dynamics. SigLab is a very sophisticated multi-channel system truly at a fraction of the price of currently available comparable equipment.

You should also browse the Application Center for specific Application Notes and User Applications for structural analysis.

What can SigLab do for noise and vibration analysis?

This is a traditional application area for "FFT spectrum analyzers". SigLab's band-translation analysis may be used to study the closely spaced spectral components produced by gear-trains, bearings, and rotating machinery in general. Using SigLab to acquire long data records and then post-processing with MATLAB's High Order Spectral Analysis and new Wavelet Toolboxes may provide new insights and analysis possibilities.

You should also browse the Application Center for specific Application Notes and User Applications for noise and vibration analysis.

What can SigLab do for audio applications?

This a question that can probably best be answered by browsing the Application Center pages and seeing what is relevant to your audio work. However, here is a short list of features relevant to audio work that should also be useful:

SigLab is an audio bandwidth measurement instrument, DC to 50 KHz.
SigLab has an extremely low-distortion measurement front end, 90 dB of dynamic range.
SigLab generates high fidelity signals.
SigLab can record, generate, and playback any signal in the audio bandwidth.
SigLab can acquire very long data records.
SigLab has many virtual instruments available including a DISTORTION ANALYZER and an OCTAVE ANALYZER.
SigLab is MATLAB-integrated making it easy to do time and frequency analysis.
SigLab is light-weight and very easy to use.

Also for more audio-related applications information, download the Application Note: Using SigLab for Audio Amplifier Product Test Applications.

How easy would it be to develop my own custom application?

We have a single MEX function called siglab that you can call from MATLAB just as you would call your own M-file function. This function is called with various arguments and is used both to setup the proper operating states of SigLab and, retrieve measurement data. Numerous examples are provided with the system to get you going.

We only use standard MATLAB programming tools, no MATLAB toolboxes are required, but you may use them if you wish. All of the measurement applications are supplied as MATLAB M-files and are available for modification.

What is the difference between ".m" and ".mi" files?

The larger applications use a programming tool called a pre-processor to make the code more efficient without loosing readability. Most development languages have this tool embedded in them but MATLAB does not.

DSP Technology created this pre-processor and calls it "MPP" for MATLAB Pre-Processor. Any file with the "mi" extension (vxx.mi) will always be accompanied by a file of the same name but with an "m" extension (vxx.m). The "mi" extension is the code used as input to the MPP where the "m" is the output from MPP and what is executed by MATLAB. This pre-processing step only takes place during code development and not during normal execution of the applications. If one compares the "mi" code to the "m" code you will see that the "mi" code is far more readable. There is extensive documentation on the MPP program in the SigLab Programmer's Reference documentation.

SigLab has both input and output channels. Can it be used as a controller?

SigLab is optimized to be a superior quality measurement system for audio range analog signals. The ADC and DAC employed to deliver this superior measurement quality are not optimum for real time control because of time delay in the conversion process. However, this delay is a constant and at lower sampling rates it becomes less of an issue. The optional package SigLab DTSS allows you to download state-space models to the hardware.

How is SigLab different from dSPACE?

Just as SigLab is optimized to be a superior quality measurement system, dSPACE is optimized for hardware-in-the-loop controller applications. For high speed control applications, use SigLab to characterize the dynamics of the plant, MATLAB/SIMULINK to create and simulate the control algorithm, dSPACE to implement the control algorithm and then use SigLab to measure and compare the design results with the simulation.

How is SigLab different from the host of data acquisition plug-in boards available today on the market?

The SigLab family offers two or four fully alias-protected, time-synchronized input signal analysis channels and one or two signal generation channels with greater than 90dB spurious free dynamic range (SFDR), better than 90dB alias protection at all measurement bandwidths and frequency translation (zoom) for narrow band measurements. These attributes clearly position SigLab as a full-blown lab-quality dynamic signal analyzer when compared to simple data acquisition boards.

How does SigLab compare with HP Analyzers?

At less than 1/2 the cost, the SigLab is a comparable in performance to the HP35670A FFT Dynamic Signal Analyzer. SigLab provides the added benefits of portability, expandability, integrated System Identification Algorithm and MATLAB integration. For applications that require higher channel counts, the HP3566A offers up to 16 channels with inferior dynamic range and bandwidth for almost twice the cost of our 16-channel SigLab 20-168 multibox configuration.

What platforms do you currently support?

SigLab currently supports only PC platforms running Windows 95, Windows 98, Windows NT 4.0, Windows 2000, or Windows XP.

A complete set of ready-to-use-out-of-the-box user interfaces (VIs) implemented in MATLAB (v5.3 or greater required) ship with SigLab. These VIs communicate with the hardware using the MATLAB MEX interface to our siglab.dll driver.

Versions of the siglab.dll for use as a development tool are also available for LabVIEW.

Spectral Dynamics, Inc. 2730 Orchard Parkway, San Jose CA 95134-2012, tel: 408-678-3500, fax: 408-678-3580