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HOW ACTIVE NOISE REDUCTION (ANR) IN AVIATION HEADSETS WORKS

Headphones are a pair of small electronic devices designed to be worn, over the head, into the user's ears, to listen to sound.  In the aviation sub-sector, manufacturers developed a headphone technology that reduces unwanted noise using active noise reduction (ANR) to achieve a quieter flight environment. Noise-reduction headphones are designed to neutralize low-frequency engine and travel noise in aircraft. Basically, when you wear a headset while flying, this technology controls the reduction of ambient sound in two ways:

Passive noise control: The body of the earphone is used to protect against unwanted sound, either in or over the ear. Most headphones also depend on sound-proof mechanisms to prevent higher-frequency noise from reaching the ear. Active noise control: This method makes use of acoustic components like microphone, amplifier, and speaker to isolate ambient sound without affecting the desirable sound. ANR technology achieves isolation of sound that creeps into the ambience with the aid of the following:


1. Microphones to pick up ambient noise.


2. Electronics that match the sound and create an opposite sound.


3. Speakers that produce the opposite signal into the ear cup to cancel out unwanted noise.


These actions as performed by these components are simultaneous.


In the aviation environment, ANR is a technology that makes hearing of in-flight important information like safety announcements easier. The ANR technology works in such a way that unwanted sound is reduced by the addition of another sound specifically to cancel out the unwanted one. Analog circuits or digital signal processing is used in achieving modern active noise control. The waveform of the background noise is analyzed through adaptive algorithms, and then the generated signal will either isolate or invert the polarity of the original signal.  The inverted signal is then amplified and a transducer creates a sound wave directly proportional to the amplitude of the original waveform.


The effect creates a destructive interference. Thereby, the volume of ambient noise is effectively reduced. ANR seeks to reduce sound emissions, for the personal comfort of the traveler, or due to issues of environmental considerations or legal compliance. However, noise-control headphones have the following drawbacks:


They cost more than regular headphones.


ANR relies on power source usually enhanced through a USB port or a battery that must be replaced or recharged periodically.  The size and weight of the ANR headphones, compared to regular headphones, increases with the addition of battery and electronics as supporting components, thereby posing carriage issues. Clearly, ANR technology is able to do less when passive noise control provided by the ear cups is effective. The degree to which manufacturers are able to get a right blend of the passive noise control devices and ANR technology will determine acceptance of their products. It is a question of personal preference what choice of headset to make. Though, higher-end headsets tend to be very comfortable whilst reducing ambient noise, there is no one headset that works best for every head.

INVERTER MICROWAVE OVENS - THE TECHNOLOGY THAT MAKES MICROWAVE THE WAY TO COOK

A microwave oven is a kitchen appliance that exposes food to the wavelength of light radiating heat in an electromagnetic spectrum.  Microwave ovens are capable of cooking a variety of foods or re-heating previously cooked food. They are rapid in heating slowly-prepared cooking items, such as hot butter, fats, and chocolate.

WHAT IS INVERTER TECHNOLOGY

Advancement in technology has enabled manufacturers to conceive the idea of a microwave oven with inverter technology.  The design of microwave oven with inverter technology ensures that the appliance derives its main source of power supply from in-built inverters. In the earlier designs of microwave oven which utilize magnetic coils or transformers to generate power, there is no stability in power generation and utilization throughout the cooking time. The function of conventional microwaves is constantly constrained by fluctuations and inadequacy in power supply, often leading to uneven cooking and cold spots.

It is this loophole that gave rise to the invention of a technology that operates steadily under stable power conditions throughout the cooking time, so as to ensure food is cooked more evenly.  In this improved technology, the inverter circuit boards replace the magnetic coil and transformer present in the old style microwave oven. The inverters improve the efficiency and effectiveness of microwave ovens by making the re-heating and cooking of food much faster and thorough. Inverter microwave oven technology is designed as an improvement on the conventional microwave oven.

 

The most significant advantage of inverter microwave oven over conventional microwaves is that its function is not hindered by inadequate or unstable power supply. The new technology cooks evenly, and improves the quality, texture and flavor of food, leaving no shrinkages and no cold spots.

This invention has greater capacity, and is lighter to carry than the conventional ones, because they use circuit boards, instead of transformers and capacitors.  It relies on power provided by the inverter, which remains constant.

The consistent and even distribution of heat also allows food to be easily- defrosted.  It is also an environmentally- friendly product that is quick and easy to use. However, this improvement in technology has only been made available by selected brands - Panasonic and GE

Panasonic is a renowned maker and distributor of home appliances especially microwave ovens. They have introduced a range of microwaves with inverter technology. The machines help keep food warm, needing no further cooking. With this state of the art technology you can enjoy double level cooking.

The Panasonic product allows two dishes to be placed in the oven and both will cook evenly and quickly. Some inverter microwave ovens reduce the defrosting time of food by nearly half because they are made to quickly defrost.


The inverter microwave oven is designed to select the proper cooking time and power level with one button pressed at a time.  Taking the popular yearnings of everyone in mind, Panasonic have developed inverter microwave oven to meet all needs.