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

What is the purpose of clock signal in an 8086 system, What is the purpose ...

What is the purpose of clock signal in an 8086 system? 8086 needs clock signal with 33%duty cycle from some external operations.8086 processor needs 5 MHZ clock signal

Flag registers , Flag Registers Flag  register  is also an  8 bit  reg...

Flag Registers Flag  register  is also an  8 bit  register. Out of 8 bit  five are  defined as flags to indicate status  of the accumulator  hence it is also called status reg

Scientists, biography of scientists in different branches

biography of scientists in different branches

Explain briefly programmable interval timer 8254, Explain with proper diagr...

Explain with proper diagram all the six modes of operation of programmable interval timer 8254. Mode 0: The output in mode 0 is initially low, and will stay low for the perio

Explain sampling and pulse modulation, Q. Explain Sampling and Pulse Modula...

Q. Explain Sampling and Pulse Modulation? In most analog circuits, signals are processed in their entirety. However, in many modern electric systems, especially those that conv

Rankine cycle and modified rankine cycle, Discuss in detail the several ene...

Discuss in detail the several energy resources and their availability. How does a Rankine cycle differ from a modified Rankine cycle? Write down the mathematical expression of m

Copy data byte 10h ldax instruction, Copy  data byte  10H LDAX  instruct...

Copy  data byte  10H LDAX  instruction Example : Copy  data byte  10H  stored at memory  location 3020 H to  the accumulator using  LDAX  instructions. Solution : To use

What are flip flop circuits in digital electronics, What are flip flop circ...

What are flip flop circuits in digital electronics? Discuss race around condition in J-K Flip Flop

Circuits, How Galvanometer can be converted int voltmeter?

How Galvanometer can be converted int voltmeter?

Reflection and retraction in cables and their calculations, How do I calcul...

How do I calculate the line-cable and cable-line values of reflection and refraction coordinates?

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