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A local oscillator is a device that generates a sinusoidal signal with a frequency such that the receiver is able to generate the correct resulting frequency, or intermediate frequency (IF), for further amplification and conversion into audio detection. There is one local oscillator in a single conversion super heterodyne receiver where heterodyning or mixing is used to generate beat frequencies, which may be the sum or the difference of two frequencies.
The local oscillator is usually adjustable and in step with the increment or decrement in the receiver frequency. For instance, if the receiver is tuned to 1,455 kilohertz (kHz) as radio frequency input (RF-in), the local oscillator frequency (LOF) may be set to 1,910 kHz for a so-called high side injection. The two signals are fed to an electronic device known as the mixer, which derives LOF - RF-in = IF or 455 kHz, which suggests why amplitude modulation (AM) broadcast receivers have about four stages of low-power amplifiers tuneable to 455 kHz.
Wiki User
∙ 11y ago
Wiki User
∙ 10y agoA local oscillator is an electronic device used to generate a signal normally for the purpose of converting a signal of interest to a different frequency using a mixer. This process of frequency conversion, also referred to as heterodyning, produces the sum and difference frequencies of the frequency of the local oscillator and frequency of the input signal of interest. These are the beat frequencies. Normally the beat frequency is associated with the lower sideband, the difference between the two.
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What is difference between self excited mixer and separately excited mixer?
location of local oscillatorself - oscillator is integral to mixerseparate - oscillator is a physically separate stage
What is the difference between crystal and local oscillator?
oscillator frequency is different.crystal working piezo electric effect
What is a local oscillation?
A local oscillator is used in a superheterodyne radio circuit for example.The incoming radio frequency is mixed with an internal local oscillator circuit to generate a new intermediate frequency (IF) .The local oscillator usually runs at a frequency of 470kHz and is generated by an inductor and capacitor(LC oscillator)
What is the difference between local oscillator and oscillator?
Oscillator is a generic word for any circuit that produces an alternative signal. The shape of the signal, its stability and its output impedance are not considered in this case. "Local oscillator" is one specific type of oscillator used in radio receiver for the purpose of frequency conversion. the input Radio Frequency( RF ) signal is "mixed" with the local oscillator signal and the subtraction of two frequencies is obtained at the output. "Mixing" in this context means: "multiplication"\ In some other context in electronics (specially audio) mixing means "adding" the mathematical operation for local oscillator is F out=Fin - F loc.osc. The output of the mixing operation can also be Fin+F loc.Osc. But this higher frequency is usually filtered out. The local oscillator needs to be a pure sine wave with a very good frequency stability and usually very stable output voltage. Recently very good "synthesizers" are introduced in the market that permit generation "programmable local oscillation"
Tell you what an intermediate frequency amplifier do?
The intermediate frequency (IF) amplifier lies between the mixer and the demodulator. The mixer shifts the input radio frequency (RF) signal into the range of the IF amplifier. The IF amplifer is a band pass amplifier, so only RF signals that are the IF frequency distance away from the local oscillator in the mixer can pass through to the demodulator. This process is called the superhetrodyne process.
What is difference between self excited mixer and separately excited mixer?
location of local oscillatorself - oscillator is integral to mixerseparate - oscillator is a physically separate stage
What is function of an oscillator?
A local oscillator is an electronic device used to generate a signal normally for the purpose of converting a signal of interest to a different frequency using a mixer. This process of frequency conversion, also referred to as heterodyning, produces the sum and difference frequencies of the frequency of the local oscillator and frequency of the input signal of interest. These are the beat frequencies. Normally the beat frequency is associated with the lower sideband, the difference between the two.
What is the difference between crystal and local oscillator?
oscillator frequency is different.crystal working piezo electric effect
What is a frequency range of LC oscillator?
depends on the oscillator and its purpose
What is the purpose of an oscillator crystal?
"A circuit within a computer that creates a series of pulses that pace the computer's electronic system. The oscillator clock synchronizes, paces and coordinates the operations of the computer's circuit." -- webopedia
What is a local oscillation?
A local oscillator is used in a superheterodyne radio circuit for example.The incoming radio frequency is mixed with an internal local oscillator circuit to generate a new intermediate frequency (IF) .The local oscillator usually runs at a frequency of 470kHz and is generated by an inductor and capacitor(LC oscillator)
What is local oscilator?
A local oscillator is used in a superheterodyne radio circuit for example.The incoming radio frequency is mixed with an internal local oscillator circuit to generate a new intermediate frequency (IF) .The local oscillator usually runs at a frequency of 470kHz and is generated by an inductor and capacitor(LC oscillator)
What is the difference between local oscillator and oscillator?
Oscillator is a generic word for any circuit that produces an alternative signal. The shape of the signal, its stability and its output impedance are not considered in this case. "Local oscillator" is one specific type of oscillator used in radio receiver for the purpose of frequency conversion. the input Radio Frequency( RF ) signal is "mixed" with the local oscillator signal and the subtraction of two frequencies is obtained at the output. "Mixing" in this context means: "multiplication"\ In some other context in electronics (specially audio) mixing means "adding" the mathematical operation for local oscillator is F out=Fin - F loc.osc. The output of the mixing operation can also be Fin+F loc.Osc. But this higher frequency is usually filtered out. The local oscillator needs to be a pure sine wave with a very good frequency stability and usually very stable output voltage. Recently very good "synthesizers" are introduced in the market that permit generation "programmable local oscillation"
Tell you what an intermediate frequency amplifier do?
The intermediate frequency (IF) amplifier lies between the mixer and the demodulator. The mixer shifts the input radio frequency (RF) signal into the range of the IF amplifier. The IF amplifer is a band pass amplifier, so only RF signals that are the IF frequency distance away from the local oscillator in the mixer can pass through to the demodulator. This process is called the superhetrodyne process.
Differetiate between LC oscillators and crystal controlled oscillators?
difference between local oscillator and controlled oscillator
How to calculate image frequency?
f (image) = 2 * f (local oscillator) + fc ................. if f ( l.o ) > fc f (image) = 2* f (local oscillator) - fc
When would a mixer in an AM superhet receiver output be zero?
The mixer output should be a signal at the IF frequency ... generally 455 KHz in an AM radio. It's the difference-frequency between the onboard local oscillator and the frequency of whatever's coming down from the antenna. Expect no RF energy from the mixer when there's no RF energy in the passband of the RF amp section ahead of the mixer ... i.e. nothing being received. If the RF section is wide open across the band, or there IS no RF section and the antenna goes straight to the mixer, and there's no mixer output, then this indicates that either you're on the far side of the moon receiving nothing across the whole AM band, or else your antenna input is grounded and the mixer is shielded.
