FFT Spectrum AnalyzerVibration and frequency analysis with a Fast Fourier transform

FFT Spectrum Analyzer Overview Performance and Flexibility

Dewesoft FFT spectrum analyzers provide all main functions for spectral frequency analysis with advanced averaging, selectable resolution (64.000 lines and more), or direct specification of the bandwidth (e.g. 0.01 Hz). Multiple channels can be displayed and analyzed in real-time in a single FFT analyzer instrument. It also allows comparing FFT data easily. 

Dewesoft FFT analyzers offer either real-time direct online frequency spectrum analysis during the measurement or offline frequency analysis on the stored data. 

Check the video on the left to get a brief overview and see why our spectrum analyzer is the best performing and most flexible spectrum analyzer in the world. 

FFT Analyzer Applications Practical Uses for FFT Analysis

Inspecting measured data in the frequency domain is often the primary part of analyzing and monitoring signals. Data from a variety of sensors are used across virtually all industries in order to solve problems, optimize designs, test prototypes, monitor machinery, and many other jobs like the ones listed below:

• Predictive machine health monitoring

• Structural dynamics analysis

• Durability testing

• Fatigue analysis

• Rotating machinery and rotating equipment analysis

• Bearing fault detection

• Order tracking analysis

• Torsional and rotational vibration analysis

• Combustion analysis

• Human body vibration tests

• Room acoustic, loudspeaker design, environmental noise analysis

• Brake noise testing

• Mechanical shock response tests, drop tests, impact tests

Typical Configurations Of Dewesoft FFT Analyzers

Basic 4 channel vibration FFT analyzer:

• SIRIUS Mini 3xACC, 1xACC+ data acquisition system

• Up to four single-axis or one triaxial IEPE/ICP® accelerometers

• Microphone (1x-4x)

• 1x Tacho

Standard 8 channel vibration FFT analyzer:

• SIRIUS DualCoreADC 6xACC, 2xACC+ DAQ system

• Up to 8 single-axis or two triaxial IEPE/ICP® accelerometers

• Microphones (1-8)

• Tacho sensors (1-2)

Portable 8-16 channel vibration FFT analyzer:

• SIRIUS R1DB or R2DB DAQ systems with SIRIUS DualCoreADC 6xACC, 2xACC+ signal conditioning slice

• Up to 16 single-axis or 5 triaxial IEPE/ICP® accelerometers

• Microphone (1-16)

• Tacho (1-4)

• Built-in computer and SSD data logger

• Built-in display and keyboard

• Li-ion battery powered

Advanced vibration FFT analyzer:

• 100+ IEPE or Charge channels in the configuration of daisy-chained SIRIUS modular slices or high-channel SIRIUS rack solutions.

Cursors and Markers Multipurpose Frequency Cursor Functions

The Dewesoft FFT analyzer allows setting multiple processing markers for automatic detection of different parameters. Our frequency analyzer offers the following markers:

• Free marker: Free markers can be freely added. The marker shows us the axis position and the amplitude of the selected graph location.

• Maximum marker: The maximum marker finds the highest amplitude in the spectrum.

• RMS marker: RMS markers will sum up all the FFT lines in the selected band and calculate the RMS value.

• Sideband marker: The sideband marker monitors the modulated frequencies to the left and right from the selected centerline.

• Harmonic marker: Shows harmonics of the fundamental frequency, and can be used to investigate signal distortion and non-linearities. 

• Damping marker: Damping markers are best to use in modal testing when we want to find out how our transfer curve is damped. We select it when we are interested in the quality factor, damping ratio, or attenuation rate of a selected peak.

• Delta marker: shows the difference in channel values between two positions of the marker.

• Kinematic marker: Advanced envelope detection is used to identify bearing frequencies and bearing faults. Kinematic markers simplify fault detection during measurement. Create your own bearing sets in the database. 

• Zoom marker: Easily zoom in the selected region of the channel(s).

• Vector cut marker: Outputs a user-defined region of a spectrum as a new channel.

• Trigger marker: Outputs 0 or 1 depending on if the user-defined trigger level is exceeded by the related signal.

All processing markers work as derived math channels and will create new channels that can be stored and used for additional analysis.

Bearing Fault Detection With Envelope Detection

Envelope detection is a standard procedure for the early detection of faults on ball bearings.

When a failure of the ball bearing occurs, it will produce ringing with a frequency that corresponds to its natural frequency. This ringing will repeat each time when a damaged part of the ball hits the ring or vice versa. In addition, the inner ring, outer ring, cage, and balls have different typical repeating frequencies depending on the geometry of the bearing and the rotational frequency. 

With DewesoftX data for bearing components are automatically managed by a bearing database. Using envelope detection and the bearing database simplifies pin-pointing critical frequency components related to specific bearing components and enables kinematic cursors to be used. 

Download Bearing Envelope Analysis brochure​​​​​​​.

Full Spectrum Math Two-sided Fourier Transform

Full Spectrum transform (aka “two-sided Fourier”) changes complex input signals from the time domain to the complex frequency domain. The input signal should be in the form of complex synchronous data (real & imaginary). Real and imaginary parts are usually gathered from two proximity probes installed along the X and Y axes. Traditional spectrum calculations provide no information regarding the direction of motion of individual frequency components on rotating shafts, but full-spectrum fills that gap.

Full-spectrum is used for signal modulation, signal demodulation, and rotor whirl analysis. 

The full spectrum transform can be performed on:

• A single value or block history

• Windowing

• Overlap and DC cutoff

Cross-spectrum and Auto Spectrum

The typically used results from FFT analysis are the Power spectra (Autospectra) determined from single individual input channels. If characteristics across multiple channels are required for analysis of correlation and phase relations, then cross power spectra are used.

With cross-spectra a reference channel is selected and cross-spectra is calculated for all channels relative to that reference channel.

Vibration Monitoring and Machine Condition Monitoring

Dewesoft also provides great tools for long-term vibration and machine condition monitoring.  What Faults Can We Detect?

• Bearing faults

• Overheating

• Shaft unbalance

• Detached mounting

• Gear-tooth failure

• Load misalignment

• Stator eccentricity

• Other machine catastrophic failures

The Historian software package provides a time-series database for long-term data storage. The database can be either located locally, on the remote server, or in the cloud. The solution is based on the InfluxDB time-series database. Historian provides several features for your historic data:

• Raw and reduced data: while raw data is always stored on the measurement unit for an in-depth analysis, a Historian takes the role of long-term reduced data storage into the cloud database.

• Data safety and retransmit: if the connection between the measurement hardware and the database is lost, the data is safely stored locally on the measurement unit and then retransmitted to the database when the connection is available.

• Trending and Analysis: Historical data can always be recalled and downloaded from the Historian database and used for trend analysis as well as for in-depth analysis and root cause identification.

Great Investment Future-Proof Application

Dewesoft FFT analyzers are a great investment for the future. Our solutions are constantly being improved, and new features are being added all the time. All updates to our FFT analysis software suite are free of charge. We offer lifetime free software updates and free software technical support.

Our industry-leading 7-year warranty on Dewesoft data acquisition systems means worry-free measurements for you. We are committed to ensuring that your investment in our measurement equipment was a good one - even when the unexpected occurs. 

Together with world-class data acquisition technology, Dewesoft provides the best FFT analysis solution your money can buy.