Fourier Archive
Negative Frequencies – What Are They?
Posted on December 13, 2011 | 1 CommentNormally when we are analysing a signal it is a purely real signal, that is it has no imaginary part. A classic example is of course a sine wave. When...
What is Synchronous (Angular) Sampling?
Posted on November 9, 2011 | No CommentsThe term synchronous data is usually applied to vibration or acoustic data that is captured from an item of rotating equipment at regularly spaced angle intervals as distinct from regularly...
10 Educational Mechanical Engineering Videos
Posted on May 17, 2010 | 5 CommentsWe’ve had a good look around YouTube and dug up a great collection of educational mechanical engineering videos. There’s a wide range of information here from simple maths tutorial to...
Amplitude And Energy Correction – A Brief Summary
Posted on September 1, 2009 | 8 CommentsAmplitude and energy correction has been and is a continuing point of confusion for many people calculating spectra from time domain signals using Fourier transform methods. The first thing to...
Data Windows : What, why and when?
Posted on July 20, 2009 | 7 CommentsBefore we discuss the use of data windows, we should first remind ourselves of three basic properties of the FFT (Fast Fourier Transform) process. First, energy information in signal must...
Vibration Monitoring Phase Measurement And The Tacho Signal
Posted on March 4, 2008 | 5 CommentsAny vibration signal may be analyzed into amplitude and phase as a function of frequency. The phase represents fifty percent of the information so it is most important to measure...
Notes On Fourier Analysis
Posted on July 29, 2003 | 14 CommentsFourier analysis takes a signal and represents it either as a series of cosines (real part) and sines (imaginary part) or as a cosine with phase (modulus and phase form)....
