Explain about amplifier noise, Electrical Engineering

Assignment Help:

Q. Explain about Amplifier noise?

Amplifier noise arises from both thermal sources (resistances) and nonthermal sources (semiconductor devices). Although nonthermal noise is not related to physical temperature and does not necessarily have a uniform spectrum like that of thermal noise, one still refers to an amplifier's noise temperature Ta, for convenience, as a measure of noisiness referred to the input. The model of a noisy amplifier is shown in Figure (a) with input noise N = ηB = kTB from a source at temperature T, and the output power given by


Nout = GN + Na = GN + GkTaB = Gk(T + Ta)B

where Na = GkTaB is the output noise power caused only by the amplifier, G is the power gain of the amplifier, and B is the bandwidth of the amplifier. Note that the amplifier noise Na is added to the amplified source noise to yield the output power in Equation. If T = T0 (i.e., room temperature), then Nout ≅ Na, and the amplifier noise dominates the source noise, which is a common occurrence. When Ta >> T0, the amplifier is very noisy, although not physically hot.

Figure (b) depicts the variation of noise temperature with frequency for a nonthermal source. Several phenomena lumped together under the term one-over-f (1/f ) noise lead to the pronounced low-frequency rise in Figure (b). Such 1/f noise is produced by transistors and certain transducers, such as photodiodes and optical sensors.

1761_Explain about Amplifier noise.png


Related Discussions:- Explain about amplifier noise

Electric current vs magnetic field, When a current is passed through a cond...

When a current is passed through a conductor, a magnetic field is created in its surroundings. We can represent this magnetic field by drawing 'field (or 'flux') lines' with two

Applications of hall effect, Applications of Hall Effect: (i)  To dete...

Applications of Hall Effect: (i)  To determine whether semiconductor is of n type or p type. (ii) To determine carrier concentration. (iii) Measurement of carrier mobili

Process of spark erosion machining, Describe the basic process of Spark Ero...

Describe the basic process of Spark Erosion (Electric Discharge) machining? Discuss the advantages of EDM as compared to other nontraditional procedures with regard to : (i)

Find the effective area of a half-wave dipole, Q. The effective area of a d...

Q. The effective area of a dipole is given by A e =0.13λ 2 . Find the effective area of a half-wave dipole at 3 GHz.

Bode plot phase ad gain margin, Using Bode plot calculate (a) Phase margin ...

Using Bode plot calculate (a) Phase margin (b) Gain margin (c) Stability of closed loop system. The open transfer function of the system is t=30/(s+2)/(s+3)Using Bode plot calcula

Find the current through the diode in the circuit, Q. A diode is connected ...

Q. A diode is connected in series with a voltage source of 5 V and a resistance of 1 k. The diode's saturation current is given to be 10 -12 A and the I-V curve is shown in Find

Define not gate - microprocessor, Define NOT Gate - Microprocessor? The...

Define NOT Gate - Microprocessor? The NOT GATE which is as well called an Inverter, is used to invert the logic state of a signal. The output Q is true while the input A is NOT

Multimeter probes, different types of probes used in multimeter

different types of probes used in multimeter

Determine the slip at which maximum torque, A three-phase, 220-V, 60-Hz, fo...

A three-phase, 220-V, 60-Hz, four-pole, wye connected induction motor has a per-phase stator resistance of 0.5 . The following no-load and blocked rotor test data on the motor are

Energy conservation , Energy conservation: NEP envisages a voluntary a...

Energy conservation: NEP envisages a voluntary approach initially for promoting energy conservation along with emphasis on labelling of appliances. Gradually as awareness incr

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