However Portable radio receivers are very widely used in other areas of modern technology, in televisions, cell phones, wireless modems, Portable radio clocks and other components of communications, remote control, and wireless networking systems.
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The Portable radio requires electric power, provided either by batteries inside the Portable radio or a power cord which plugs into an electric outlet.
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However FM Portable radio is less susceptible to interference from Portable radio noise and has higher fidelity; better frequency response and less audio distortion, than AM.
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Besides the broadcast receivers described above, Portable radio receivers are used in a huge variety of electronic systems in modern technology.
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The oscillating electric and magnetic fields of the Portable radio wave push the electrons in the antenna back and forth, creating an oscillating voltage.
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Practical Portable radio receivers perform three basic functions on the signal from the antenna: filtering, amplification, and demodulation:.
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Power of the Portable radio waves picked up by a receiving antenna decreases with the square of its distance from the transmitting antenna.
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The degree of amplification of a Portable radio receiver is measured by a parameter called its sensitivity, which is the minimum signal strength of a station at the antenna, measured in microvolts, necessary to receive the signal clearly, with a certain signal-to-noise ratio.
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An audio signal, representing sound, as in a broadcast Portable radio, is converted to sound waves by an earphone or loudspeaker.
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The strength of the signal received from a given transmitter varies with time due to changing propagation conditions of the path through which the Portable radio wave passes, such as multipath interference; this is called fading.
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Marconi's initial Portable radio system had relatively poor tuning limiting its range and adding to interference.
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Today these simple Portable radio receivers are constructed by students as educational science projects.
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Crystal radio used a cat's whisker detector, invented by Harrison H C Dunwoody and Greenleaf Whittier Pickard in 1904, to extract the audio from the radio frequency signal.
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Advent of Portable radio broadcasting increased the market for Portable radio receivers greatly, and transformed them into a consumer product.
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At the beginning of the 1920s the Portable radio receiver was a forbidding high-tech device, with many cryptic knobs and controls requiring technical skill to operate, housed in an unattractive black metal box, with a tinny-sounding horn loudspeaker.
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Portable radio was the first to give a correct explanation of how De Forest's triode tube worked.
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Portable radio invented the feedback oscillator, regenerative receiver, the superregenerative receiver, the superheterodyne receiver, and modern frequency modulation .
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Invention of the transistor in 1947 revolutionized radio technology, making truly portable receivers possible, beginning with transistor radios in the late 1950s.
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In digital Portable radio broadcasting systems such as Digital Audio Broadcasting, the analog audio signal is digitized and compressed, typically using a modified discrete cosine transform audio coding format such as AAC+.
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Since the Graphical User Interface to the Portable radio has considerable flexibility, new features can be added by the software designer.
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