Chapter 7 Part II.pdf - COMMUNICATION SYSTEM EECB353 CHAPTER 7 PART 2 NOISE ANALYSIS Dr Norazizah Mohd Aripin Department of Electronics Communication

# Chapter 7 Part II.pdf - COMMUNICATION SYSTEM EECB353...

• 19

This preview shows page 1 - 7 out of 19 pages.

COMMUNICATION SYSTEM EECB353 CHAPTER 7- PART 2 NOISE ANALYSIS Dr Norazizah Mohd Aripin Department of Electronics & Communication Engineering Universiti Tenaga Nasional 2 Gain and Attenuation Most circuits in are used to manipulate signals to produce a desired relectronic communication esult. All signal processing circuits involve: Gain Attenuation 3 Gain and Attenuation Gain means amplification. It is the ratio of a circuit’s output to its input . The number obtained by dividing the output by the input shows how much larger the output is than the input. A positive (+) dB value indicates that the output power is greater than the input power which indicates power gain. A V = = output input V out V in 4 Most amplifiers are also power amplifiers, so the same procedure can be used to calculate power gain A P where P in is the power input and P out is the power output. Power gain ( A p ) = P out / P in An amplifier is cascaded when two or more stages are connected together. The overall gain is the product of the individual circuit gains . Gain and Attenuation A 1 A 2 A 3 A T = A 1 x A 2 x A 3 5 Example 1:a)The power output of an amplifier is 6 watts (W). The power gain is 80. What is the input power?b) Three cascaded amplifiers have power gains of 5, 2, and 17. The input power is 40 mW. What is the output power?Gain and Attenuation 6  • • • 