orders Archive
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...
Video: Noise & Vibration From Rotating Machines
Posted on October 4, 2011 | No CommentsThis is complete version of the video illustrating my recent article How To Measure Noise & Vibration In Rotating Machines. This video was previously published on the blog in 3 parts....
How To Analyze Noise & Vibration In Rotating Machines
Posted on August 9, 2011 | 3 CommentsIn this article we will look at the basic steps behind a simple rotating machinery study. We won’t look in great detail at some of the techniques involved – we deal with...
Measurement And Analysis Of Torsional Vibration
Posted on October 17, 2008 | 13 CommentsTorsional vibration is of key importance in the area of vehicle development and refinement. The main contributory source is the engine where periodically occurring combustion cycles cause variation in the...
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...
Orders v Time – Comparing Overall Levels
Posted on October 23, 2007 | 4 CommentsBy combining a speed signal with a data signal and using the Short Time FFT algorithm (Hopping FFT), it is possible to extract order data directly as a function of...
Sound Steering
Posted on September 12, 2007 | No CommentsThe requirement was to develop a ‘standard’ test for assessing the sound quality of power steering pumps in vehicles. Measurements needed to be objective so that the method would be...Measuring Torsional Crank Shaft Jitter
Posted on June 24, 2007 | No CommentsUsing Prosig’s P8000 series data acquisition system with DATS signal analysis software, torsional analysis (crank jitter) was performed on an automotive engine attached to an engine dynamometer. The significance of...Order Cuts And Overall Level
Posted on February 25, 2007 | No CommentsOrder cuts are taken from a set of FFTs, each one at a different rpm. The rms level is then found as the Square root of the Sum of the...
Exhaust Development Using A Prosig P8000 System
Posted on February 20, 2006 | 2 CommentsThe following note describes an application of the Prosig P8000/DATS system in the refinement of an automotive exhaust muffler design for a major after-market exhaust manufacturer in Europe. The particular...Torsional Vibration, Tacho Pulses And Aliasing
Posted on January 12, 2006 | 3 CommentsWith shafts, gears and the like, the general method of determining the rotational speed is to use some form of tachometer or shaft encoder. These give out a pulse at...
Analyzing Shaft Twist And Repairing Damaged Tachos
Posted on October 19, 2005 | 1 CommentA shaft has been instrumented with two shaft encoders, one at each end. Each shaft encoder gives out a once/rev pulse and a 720 pulses/rev signal. Each signal was digitised...A Simple Noise Test
Posted on August 26, 2005 | 2 CommentsIn a recent article we described how the Prosig P8000 hardware and DATS software had been used to help Dalmeny Racing diagnose a problem with an exhaust bracket on their...Average Waterfalls Or Average Orders?
Posted on June 14, 2005 | No CommentsOne would expect that averaging waterfalls and then extracting orders would give the same result as extracting orders from individual waterfalls and then averaging them. This is not the case.
Audio Equalisation Filter & Parametric Filtering
Posted on May 17, 2005 | No CommentsWhen working with audio signals a common requirement is to be able to equalise, cut or boost various frequency bands. A large number of hardware devices on the market provide...
Measuring Torsional Twist & Vibration Along a Shaft or Through a Geartrain
Posted on May 15, 2002 | 3 CommentsThe measurement of the twist angle between two points along a shaft or through a gear train may be derived from a pair of tacho signals, one at each end...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....
