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 by upsample and downsample and why we may need to use it.…

What Are Vibration, Torsional Vibration & Shaft Twist?

When analyzing rotating shafts some terms are often confused. This post will attempt to explain the differences. So, what are vibration, torsional vibration and twist? What is Vibration? We measure at least one sensor on one channel of our measurement device…

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 Nyquist frequency are, however, less well understood. Most engineers will understand the…

How to avoid a ground loop – It’s not only a problem with accelerometers

When using modern, high technology measurement devices one can often be tripped up by the simplest things. The most common is the ground loop. Time and again this issue rears its head. So, let’s talk about how to avoid a…

Speech Articulation Index – What Does It Mean?

There are many ways to calculate speech articulation index and each has its advantages in different applications. Prosig’s DATS includes four methods for evaluating the Articulation Index as seen in the table below. All four methods are essentially the same and they…

Processing pump data – a classic case of amplitude modulation

When dealing with some vibration data from a pump, we observed some strange phenomena in the data. It turned out to be a classic case of amplitude modulation. Here we explain what that means.

How do we design or modify a system to avoid resonance?

After finding the natural frequency of a system, what could be done to stop or reduce the systems resonance being excited? Basically put, how do we avoid resonance This is simple in theory, but not always so simple in practice.…

Three Methods For Analyzing Vibration In Rotating Components

In this post we will first look at how to process data from rotating machinery. Then we will focus on shaft or gear train twist. Let’s look at 3 different ways to measure and analyse rotating shafts. Each one has…

What Is Resonance? (Part 3)

In the previous two articles (What Is Resonance? (Part 1) & What Is Resonance (Part 2)) in this series we have looked at how we can identify a resonant frequency. Now we will discuss what happens next. What do we…

What Are AC and DC Coupling?

This is an important subject to understand when working in the signal processing field. In terms of AC and DC Coupling, what is Coupling? Quite simply, coupling is the transfer of energy from one medium to another, for example, from…

What is Resonance? (Part 2)

This article is a follow on from What Is Resonance? (Part 1) and answers some of the issues not covered in that post. How do you find the resonant frequency in the real world? What do you do when there…

Video: How To Calibrate Microphones & Accelerometers

Here are two videos on a relatively simple, but sometimes misunderstood procedure – how to calibrate microphones & accelerometers

Understanding Filter Characteristics

Recently when discussing with an engineering student the characteristics of filters, it became clear that some confusion exists around this subject area. This note attempts to explain the differences between types of filter and the effects of the parameters of those…

A Simple Capture, Analysis and Report (Part 4)

This is the final part of our four part tutorial. This adds a report to the worksheet we developed in part 3.

A Simple Capture, Analysis and Report (Part 3)

Today we have the third of our four part tutorial. Here we show how to quickly build a worksheet to analyze the data we captured in parts one and two. Part four will follow on Monday

A Simple Capture, Analysis and Report (Part 2)

Part two of the four tutorials showing a simple setup to capture, analyze and produce a report using Prosig’s DATS software and P8000 hardware. This part deals with setting up realtime displays in the data capture. Part three to follow…

A Simple Capture, Analysis and Report (Part 1)

The first part of a series of four tutorials showing a simple setup to capture, analyze and produce a report using Prosig’s DATS software and P8000 hardware. Part 2 coming soon…

What Is The Difference Between Single Ended & Differential Inputs?

Prosig P8000 systems use differential inputs, but what are they and why are they so special? This subject is not always fully understood and, therefore, the focus of this article is to try to make the difference clearer and explain…

Converting Acceleration, Velocity & Displacement

From time to time I meet engineers who are interested in the conversions between acceleration, velocity and displacement. Often, they have measured acceleration, but are interested in displacement or vice versa. Equally, velocity is often used to find acceleration. This article outlines the nature of the conversion between these units and will suggest the preferred method for doing so. .

How To Float Output Windows in DATS Acquisition V4

Nowadays it is easy to attach extra screens to most computers. It is not uncommon to have a two or even three monitor setups. Even with laptops it is fairly easy to attach either a full size extra monitor or…

Comparison Between Sound Intensity Probes and Acoustic Cameras

Sometimes we are asked about the differences between an acoustic camera and a sound intensity probe and which of the two is better for a particular application. There is no straightforward answer as they are quite different pieces of equipment,…

What is the difference between microphone types?

I’m often asked what is the difference between free field microphones, diffuse field microphones and pressure microphones. For a run-of-the-mill ½ inch microphone the short answer is nothing. However the long answer is a bit more involved. Basically if the…

A Simple Frequency Response Function

The following article will attempt to explain the basic theory of the frequency response function. This basic theory will then be used to calculate the frequency response function between two points on a structure using an accelerometer to measure the…

What Is A Strain Gauge?

A strain gauge is an electrical sensor which is used to accurately measure strain in a test piece. Strain gauges are usually based on a metallic foil pattern. The gauge is attached to the test piece with a special adhesive.…

What Are dB, Noise Floor & Dynamic Range?

Most engineers are probably familiar with or have come across the decibel or dB as a unit of measurement. Its most common use is in the field of acoustics where it is used to quantify sound levels. However, as will…

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