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1/f noise; A-weighting; Ambient noise level; Antenna noise temperature; Artificial noise; Audio noise reduction; Audio system measurements; Black noise; Blue noise; Burst noise; Carrier-to-receiver noise density; Channel noise level; Circuit noise level; Colors of noise; Comfort noise; Comfort noise generator; Cosmic noise; Crackling noise; DBa ...
If electrons flow across a barrier, then they have discrete arrival times. Those discrete arrivals exhibit shot noise. The output noise level of a shot noise generator is easily set by the DC bias current. Typically, the barrier in a diode is used. [4] Different noise generator circuits use different methods of setting the DC bias current.
A "quiet zone" sign, indicating that "no person operating any vehicle within the zone shall sound the horn or other warning device of the vehicle, except in an emergency" [1] Noise regulation includes statutes or guidelines relating to sound transmission established by national, state or provincial and municipal levels of government
Highway noise is today less affected by motor type, since the effects in higher speed are aerodynamic and tire noise related. Other contributions to the reduction of noise at the source are: improved tire tread designs for trucks in the 1970s, better shielding of diesel stacks in the 1980s, and local vehicle regulation of unmuffled vehicles.
Electronic noise control: Electronics, sensors, and computers are also employed to cancel noise by using phase cancellation which matches the sound amplitude with a wave of the opposite polarity. This method employs the use of an active sound generating device, such as a loudspeaker to counteract ambient noise in an area.
Thus, receivers with a narrow bandwidth have a higher sensitivity than receivers with a large bandwidth and input noise can be decreased by cooling the receiver input stage. A noise diode is a device which has a defined excess noise ratio (ENR). When the diode is off (unpowered) the noise from it will be thermal noise defined by the above formula.
Ambient noise level is measured with a sound level meter. [4] It is usually measured in dB relative to a reference pressure of 0.00002 Pa, i.e., 20 μPa (micropascals) in SI units. [5] This is because 20 μPa is the faintest sound the human ear can detect. [5] A pascal is a newton per square meter. The centimeter-gram-second system of units ...
Background noise is an important concept in setting noise levels. Background noises include environmental noises such as water waves , traffic noise , alarms , extraneous speech , bioacoustic noise from animals, and electrical noise from devices such as refrigerators , air conditioning , power supplies , and motors .