# Tag: Nyquist

## How Do I Upsample and Downsample My Data?

This post covers how to upsample and downsample data and the possible pitfalls of this process. Before we cover the technical details let us first explain what we mean

## The Effect of the Nyquist Theory on Rotational Order Analysis

Nyquist theory is generally understood, but this understanding usually relates to time sampling and the conversion to the frequency domain. Rotational order analysis and the effect of the

## RMS From Time History And FFT Spectrum

The RMS of a time history is a measure of the signal’s overall energy and is often used when extracting features from a signal for prognosis and trending

## Which Should I Use? Real & imaginary? Or magnitude & phase?

In 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

## Aliasing, Orders and Wagon Wheels

These days most people collecting engineering and scientific data digitally have heard of and know of the implications of the sample rate and the highest observable frequency in

## 10 Educational Mechanical Engineering Videos

We’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

## Interpolation Versus Resampling To Increase The Sample Rate

These 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

## Evaluating A Closed Loop Control System For High Pressure Pumps

Prosig 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

## What Is A Fourier Transform?

A Fourier Transform 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

## Order Tracking, Frequency and Hertz

The 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