Prosig Signal Processing Blog

Notes, tutorials, news and articles on digital signal capture, processing, techniques and applications

April 14, 2008

WHAT ARE dB, NOISE FLOOR & DYNAMIC RANGE?

By James Wren, Application Engineer, Prosig

TitleMost 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 be explained in this article, it is also useful for a wide variety of measurements in other fields such as electronics and communications.

One particular use of dB is to quantify the dynamic range and accuracy of an analogue to digital conversion system. This applies to Prosig’s P8000 range of data acquisition hardware where the noise floor, dynamic range and resolution are all specified in terms of dB. read »»»

May 23, 2007

WHAT IS RESONANCE?

By James Wren, Application Engineer, Prosig

ResonanceFirst, in order to explain resonance we have to explain the terms we will use.
• A resonance is a particular frequency.
• A period is the amount of time it takes to complete one cycle
• The number of cycles in one second is the frequency of an oscillation.
• Frequency is measured in Hertz, named after the 19th-century German physicist Heinrich Rudolf Hertz
• A single Hertz is equal to one cycle per second.
read »»»

March 29, 2007

EVALUATING A CLOSED LOOP CONTROL SYSTEM FOR HIGH PRESSURE PUMPS

By James Wren, Application Engineer, Prosig

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 test cell has 8 pumps continually on test. Each pump is instrumented with a revolution or tachometer sensor, giving a once per revolution tachometer pulse. Additionally, there are various analogue transducers on each pump which measure parameters, such as pressure at the pump inlet and outlet. read »»»

September 11, 2006

MEASURING FOR SUCCESS

By James Wren, Application Engineer, Prosig

The following application note shows the steps taken to perform a structural analysis on an automotive exhaust pipe structure with the aim of improving the structural damping properties of the exhaust pipe mount. This application note is a follow up to a previous article – “Preventing Component Failure In The Fast Lane”.

A recent signal processing application note described how the Prosig sponsored Dalmeny Racing Formula Ford Team, whilst contesting the UK Formula Ford 1600cc championship, suffered several minor structural failures on a particular part of an exhaust pipe mount. Prosig dispatched a team of engineers and after a brief survey of the damage the Prosig engineers made an outline assessment “Our initial thoughts are that the exhaust itself might be resonating at particular engine speeds, thus causing some shear forces in the mount, which could then in turn cause stresses in the material leading to cracking and eventually failure.” read »»»

June 6, 2006

MADE TO MEASURE

By James Wren, Application Engineer, Prosig

Made to MeasureIn this note the different types of transducers that can be used with the Prosig P8000 series data acquisition system are discussed. The article deals with the design and function of the different types of transducer and the applications they are normally associated with. read »»»

May 17, 2006

FATIGUE & DURABILITY TESTING

By James Wren, Application Engineer, Prosig

The following application note describes the test and measurement process for the fatigue testing and development cycle of a component. Strain gauges were used to monitor the strain levels in a particular suspension component. The component had been known to fail at various intervals. A predicted life for the component was required to analyse the feasibility of the its continued use or to see if a design change was required. The component under test (Figure 1) was an automotive suspension component, specifically a tie rod. The testing was carried out by a major automotive manufacturer. read »»»

February 20, 2006

EXHAUST DEVELOPMENT USING A PROSIG P8000 SYSTEM

By James Wren, Application Engineer, Prosig

The 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 vehicle under test was required by local legislation to have an overall radiated noise level of less than 70 dB. When tested, the vehicle was found to be producing 71.8 dB of radiated noise. The design of the exhaust system clearly needed to be reviewed and modified. read »»»

August 26, 2005

A SIMPLE NOISE TEST

In 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 Formula Ford racing car. Whilst the car was instrumented for structural tests on the exhaust the opportunity was taken to also take some noise and vibration readings during an engine run up. It was felt that these would provide some useful “real world” data as well as maybe providing some extra information regarding the exhaust bracket failure. After analysing and animating the hammer data it became clear that the engine runup data wouldn’t be needed. However, it was decided that some analysis should be carried out to see if the noise and vibration data backed up the conclusions of the other tests. read »»»

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