In electronics, a local oscillator (LO) is an electronic oscillator used with a mixer to change the frequency of a signal. This frequency conversion process, also called heterodyning, produces the sum and difference frequencies from the frequency of the local oscillator and frequency of the input signal.
Why local oscillator is used in superheterodyne receiver?
The superheterodyne receiver uses one or more mixers and local oscillators to convert the received signal channel to another frequency band for more convenient filtering and amplification.
Which oscillator is used in local oscillator?
triode
Why local oscillator frequency is higher?
The reason a higher frequency is commonly chosen in a Super heterodyning receiver, is to leave more distance between the difference or intermediate frequency and the other two frequencies so that the IF signal can be more easily passed through a filter and attenuate the the original two signals.
Which oscillator is used as local oscillator in superheterodyne radio receiver?
The signal is then fed into a circuit where it is mixed with a sine wave from a variable frequency oscillator known as the local oscillator (LO). The mixer uses a non-linear component to produce both sum and difference beat frequencies signals, each one containing the modulation contained in the desired signal.
What type of local oscillator is used in most modern receivers?
What type of local oscillator is used in most modern receivers? Frequency synthesizers.
Which device is used as an oscillator?
An oscillator is a mechanical or electronic device that works on the principles of oscillation: a periodic fluctuation between two things based on changes in energy. Computers, clocks, watches, radios, and metal detectors are among the many devices that use oscillators.
What is the frequency of the local oscillator?
The r.f. circuits and the local oscillator are all tuned by varactor diodes. The tuning range is from 470−860 MHz. At these frequencies, the circuit Q s are relatively low, with values of about 30 at 600 MHz.