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The carbon microphone, also known as carbon button microphone, button microphone, or carbon transmitter, is a type of microphone, a transducer that converts sound to an electrical audio signal. It consists of two metal plates separated by granules of carbon. One plate is very thin and faces toward the speaking person, acting as a diaphragm.
In control engineering, a single-input and single-output (SISO) system is a simple single-variable control system with one input and one output. In radio, it is the use of only one antenna both in the transmitter and receiver .
Francis Blake was born in Needham, Massachusetts on December 25, 1850, the son of Caroline Burling (Trumbull) and Francis Blake, Sr. [1]. In 1879, he invented a carbon microphone for use in the telephone, and patented [2] [3] [4] it shortly after Thomas Edison invented a similar microphone that also used carbon contacts.
It is usually used to turn on a transmitter or recorder when someone speaks and turn it off when they stop speaking. It is used instead of a push-to-talk button on transmitters or to save storage space on recording devices. On cell phones, it is used to save battery life. Intercom systems that use a speaker in a room as both a speaker and a ...
Most of these were connected to the set being controlled by wires, but the Philco Mystery Control (1939) was a battery-operated low-frequency radio transmitter, [14] thus making it the first wireless remote control for a consumer electronics device. Using pulse-count modulation, this also was the first digital wireless remote control.
Single-ended signaling is the simplest and most commonly used method of transmitting electrical signals over wires. One wire carries a varying voltage that represents the signal, while the other wire is connected to a reference voltage, usually ground .
The remote keyless systems using a handheld transmitter first appeared on the French made Renault Fuego in 1982, [4] and as an option on several American Motors vehicles in 1983, including the Renault Alliance. The feature gained its first widespread availability in the U.S. on several General Motors vehicles in 1989. [citation needed]
A direct-conversion receiver (DCR), also known as a homodyne, synchrodyne, zero intermediate frequency or zero-IF receiver, is a radio receiver design that demodulates the incoming radio signal using synchronous detection driven by a local oscillator whose frequency is identical to, or very close to the carrier frequency of the intended signal.