Explain the operation of oscillators, Electrical Engineering

Assignment Help:

Q. Explain the operation of oscillators.

Oscillator is a circuit that changes dc energy from the power supply into ac energy. An amplifier provided with a positive feedback becomes an oscillator and it produces an output signal even though there is no external input signal. The function of the oscillator is just the reverse of a rectifier. The block diagram of an oscillator is given below:

449_Explain the operation of oscillators.png

Consider the block diagram of figure. A voltage source Vin drives the input terminals of an amplifier. The amplifier output voltage is AVin and it drives the feedback network producing a feedback voltage Vf = AbVin. If the circuit of the amplifier and the feedback network provide correct phase shift, then this feedback voltage Vf will be in phase with signal Vin that drives the input terminals of the amplifier. Now, if switch is closed and simultaneously the voltage source Vin is removed, the feedback voltage Vf will drive the input terminals of the amplifier. If Ab is less than 1, AbVin will be less than Vin, the signal feedback is not sufficient to drive the amplifier and the feedback circuits and the output signal will die out. If Ab is greater than 1, the output signal builds up resulting in oscillations with growing magnitude. If Ab is equal to 1, AbVin = Vin and the output voltage is a sine wave whose amplitude remains constant.

When the oscillator circuit is switched on, the only signal source at input is the noise voltage generated by the resistors. This noise voltage gets amplified and then appears at the output. This amplified noise now drives the feedback circuit, which can be a resonant, or a phase shift network. The feedback voltage is maximum at a particular frequency and also the phase shift for positive feedback is correct at this frequency. So we get oscillations at one frequency only though noise voltage contains all frequencies.


Related Discussions:- Explain the operation of oscillators

Determine downink of a cdma system, Consider the point-to-point radio link ...

Consider the point-to-point radio link introduced in problem 9. By how much must transmit power be increased to maintain the maximum BER of 10-5 if the channel is flat Rayleigh-fad

Difference equation of transfer function, Now you have to digitally impleme...

Now you have to digitally implement this circuit. Compute a difference equation which if you implement will behave exactly like this circuit.

Drawing, #question what are the types of lines used there and their applica...

#question what are the types of lines used there and their application ..

Explain working of inverting amplifier, Q. Explain working of Inverting Amp...

Q. Explain working of Inverting Amplifier? One common op-amp circuit is shown in Figure. For the case of finite voltage gain Ao of an op amp that is otherwise ideal, the output

Calculate the current flow using norton theorem, Calculate the current flo...

Calculate the current flow in 30Ω resistor for the circuit in figure using Norton Theorem.

What is open-loop voltage gain, Q. What is Open-loop voltage gain? The ...

Q. What is Open-loop voltage gain? The op amp amplifies the difference vd between the voltage on the noninverting (+) terminal and the inverting (-) terminal; see Figure. The t

Semiconductors, Charge density I n a semiconductor

Charge density I n a semiconductor

What do you mean by negative clamper, Q. What do you mean by Negative Clamp...

Q. What do you mean by Negative Clamper? During the positive half cycle the diode conducts and acts like a short circuit. The capacitor charges to peak value of input voltage V

Trends, what is south africas perspective?

what is south africas perspective?

Pid controller design, PID controllers are popularly adopted in a wide rang...

PID controllers are popularly adopted in a wide range of industrial processes. The objective of this design practical is to study the way this PID controller changes system dynamic

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd