Nyquist Archive
Which Should I Use? Real & imaginary? Or magnitude & phase?
Posted on May 4, 2011 | 7 CommentsIn one of our recent articles a question was asked regarding the practical use of real & imaginary type plots compared with modulus & phase type plots. In general, noise...
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...
Interpolation Versus Resampling To Increase The Sample Rate
Posted on June 22, 2009 | 5 CommentsThese are two different techniques aimed at different objectives. First consider a simple sinewave that has been sampled close to the Nyquist frequency (sample rate/2). Visually this looks very pointy. We...Evaluating A Closed Loop Control System For High Pressure Pumps
Posted on March 29, 2007 | 1 CommentProsig were recently involved in the validation of a closed loop control system for an automotive pump supplier. The customer has a large number of test cells, each test cell...
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)....Frequency, Hertz & Orders
Posted on February 3, 2002 | No CommentsThe most common form of digitising data is to use a regular time based method. That is data is sampled at a constant rate specified as a number of samples/second....
Data Decimation. What Do I Do?
Posted on June 6, 2001 | No CommentsSometimes we have digitised data at a much higher rate than we need. How can we reduce the sampling rate? If I wanted to say halve the sample rate can...
Removing Phase Delay Using Phaseless Filtering
Posted on June 6, 2001 | No CommentsIn many instances we need to filter a signal to remove unwanted frequencies. If we use classical filters such as Butterworth, Chebyshev or even Bessel then a phase delay is...
