0
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"
IF = Intermediate Frequency
A crystal oscillator is an oscillator circuit whose frequency of operation is primarily decided by the frequency for which the crystal was cut.
An intermediate frequency oscillator is the oscillator which operates at a specific frequency depending on it's purpose. For an FM receiver, the IF is 10.7MHz. For an AM receiver, the IF is 455kHz. For TVs, it's different for the luminance/chrominance/audio information.
When two frequencies are sent to a nonlinear mixer circuit, the frequencies output include both the original inputs, F2-F1, and F2+F1 where F2 is the higher frequency. So, if Fs (signal from antenna) and Fi (intermediate frequency, say 10.7MHz) are both sent to a nonlinear mixer, then Fi+Fs (along with others) will be output, which means that your desired signal (music from the radio, etc.) is NOW on a 10.7MHz carrier, where it can be singled out (via filter) and the signal is worked with at 10.7MHz instead of potentially 107+MHz. It's a lot easier to design a circuit at 10.7MHz then it is at 107+MHz.
If the crystal is cut to resonate at the IF, a crystal oscillator can be used for the IF oscillator. So, the IF oscillator COULD be a crystal oscillator. Hope that helps :-)
Add your answer:
Earn +20 pts
What is the difference between crystal and local oscillator?
oscillator frequency is different.crystal working piezo electric effect
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 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)
Difference between Harmonic oscillator and anharmonic oscillator?
In case of HARMONIC OSCILLATOR the relation b/n FORCE AND DISPLACEMENT is LINEAR but in the case of ANHARMONIC OSCILLATOR relation b/n force and displacement is not linear.Hence this non-linearity arises the fact that the spring is not capable of exerting a restoring force that is proportional to the displacement.
What is the purpose of a local oscillator in mixer?
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.
What is the difference between crystal and local oscillator?
oscillator frequency is different.crystal working piezo electric effect
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 are the Difference between RC oscillator And LC oscillator?
The difference between an RC and LC is that the frequency - determining device in the RC oscillator is not a tank circuit. LC can operate with A or C biasing, while RC can only operate with A.
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 difference between generator and oscillator?
A generator is used to convert mechanical energy to electrical energy. An oscillator is used to convert dc to ac
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 colpitts and clapp oscillator?
The Clapp oscillator is a variation of the Colpitts oscillator that includes an additional capacitor in series with the inductor to improve frequency stability. This additional capacitor in the Clapp oscillator helps reduce the effect of the active device's parasitic capacitance, leading to better frequency stability compared to the Colpitts oscillator.
What is the difference between colpitts and hartley ossilator?
colpitts oscillator has two coils in series and one capacitor in parallel. hartley oscillator has one capacitor and one coil in parallel
Difference between Harmonic oscillator and anharmonic oscillator?
In case of HARMONIC OSCILLATOR the relation b/n FORCE AND DISPLACEMENT is LINEAR but in the case of ANHARMONIC OSCILLATOR relation b/n force and displacement is not linear.Hence this non-linearity arises the fact that the spring is not capable of exerting a restoring force that is proportional to the displacement.
What is the purpose of a local oscillator in mixer?
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.
What is difference between oscillator and regulator ic?
oscillator is which oscillates to a required proportion in order to generate signal with required frequency. whereas, regulator limits the signal to a predefined value and offers a constant out put through out
