The process of separating or extracting the modulation from a signal is called demodulation or detection. For amplitude modulation, the process of demodulation or detection can be accomplished very simply using a diode, or it may be achieved in other ways that provide more effective demodulation of the waveform. As amplitude modulation is still widely used as a result of its simplicity, receivers incorporating AM demodulators are manufactured in quantities of many millions each year. Within these radios a simple AM detector consisting of a diode is used. AM demodulation or detection process In order to look at the amplitude demodulation process it is necessary to first look at the format of an AM signal. An AM signal consists of …
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AM
In order that a steady radio signal or “radio carrier” can carry information it must be changed or modulated in one way so that the information can be conveyed from one place to another. There are a number of ways in which a carrier can be modulated to carry a signal – often an audio signal and the most obvious way is to vary its amplitude. Amplitude Modulation has been in use since the very earliest days of radio technology. The first recorded instance of its use was in 1901 when a signal was transmitted by a Canadian engineer named Reginald Fessenden. To achieve this, he used a continuous spark transmission and placed a carbon microphone in the antenna lead.…