The error signal e(n) is measured by the error sensor in acoustic chamber where the primary noise signal d(n) and anti-noise
signal y(n) is mixed.
Extremely robust transducers are integrated into the exhaust system, and with the anti-noise
technology they abate exhaust noise and, when necessary, the system can actively shape the noise.
In January the Birmingham Airport anti-Noise
Group and Friends of the Earth launched the Flyagra campaign and website to persuade the council to turn down the airport's application for planning permission.
This would enable local authorities to implement anti-noise
measures such as diverting train and automobile traffic away from schools and residential areas--and give us all a little peace and quiet.
The microphone, located close to the noise source, captures the noise of internal fans, processes an anti-noise
signal in the ANC digital signal processing (DSP)-based controller and transmits the anti-noise
via the speaker.
It will give directions on navigation, engaging the enemy and have an anti-noise
gadget to let airmen cope with the 1,500mph din.
For the third type of customer, and to complete its brake pad offer, Ferodo[R] has developed ThermoQuiet[R], which combines excellent stopping power, enhanced anti-noise
features, and outstanding product life.
Target markets for this product include vibration absorption segments for rail transportation, anti-noise
paving tiles, sports surfaces, playground surfaces and panels for railway crossings.
However, the National Noise Association (an umbrella organisation for several anti-noise
protest groups) even uses the upbeat slogan that this is "The Year of the National Noise Strategy", which probably won't get many pulses racing.
And an anti-noise
team from the city council moved in to confiscate two hi-fis and amplifiers, as well as 50 CDs.
The low-noise sensor is made of ETFE (ethylene-tetrafluorethylene) or PVDF (polyvinylidene fluoride) with patented anti-noise
shielding and is robust under exposure to various chemicals and varying temperatures.
Which is where the admiration of the anti-noise
campaigners and the anti-pollution lobby starts to be tinged with the worry of those concerned with road safety.