Superheterodyne Receiver - Design and Principle of Operation

Design and Principle of Operation

The principle of operation of the superheterodyne receiver depends on the use of heterodyning or frequency mixing. The signal from the antenna is filtered sufficiently at least to reject the image frequency (see below) and possibly amplified. A local oscillator in the receiver produces a sine wave which mixes with that signal, shifting it to a specific intermediate frequency (IF), usually a lower frequency. The IF signal is itself filtered and amplified and possibly processed in additional ways. The demodulator uses the IF signal rather than the original radio frequency to recreate a copy of the original information (such as audio).

The diagram at right shows the minimum requirements for a single-conversion superheterodyne receiver design. The following essential elements are common to all superhet circuits: a receiving antenna, a tuned stage which may optionally contain amplification (RF amplifier), a variable frequency local oscillator, a frequency mixer, a band pass filter and intermediate frequency (IF) amplifer, and a demodulator plus additional circuitry to amplify or process the original audio signal (or other transmitted information).

Read more about this topic:  Superheterodyne Receiver

Famous quotes containing the words design, principle and/or operation:

    To nourish children and raise them against odds is in any time, any place, more valuable than to fix bolts in cars or design nuclear weapons.
    Marilyn French (20th century)

    The principle of fashion is ... the principle of the kaleidoscope. A new year can only bring us a new combination of the same elements; and about once in so often we go back and begin again.
    Katharine Fullerton Gerould (1879–1944)

    You may read any quantity of books, and you may almost as ignorant as you were at starting, if you don’t have, at the back of your minds, the change for words in definite images which can only be acquired through the operation of your observing faculties on the phenomena of nature.
    Thomas Henry Huxley (1825–95)