What is frequency translation and product modulation, Electrical Engineering

Assignment Help:

Q. What is Frequency Translation and Product Modulation?

The basic operation needed to build modulators is the multiplication of two signals. Whenever sinusoids are multiplied, frequency translation takes place. Figure 14.2.1(a) shows a product modulator, which multiplies the signal x(t) and a sinusoidal carrier wave at frequency fc to yield

2180_What is Frequency Translation and Product Modulation.png

Choosing x(t) to be a low-pass signal with bandwidth W << fc, Figure (b) depicts the relationship between xc(t) and x(t). The modulated wave xc(t) can now be seen to have a bandpass spectrum resulting from frequency translation, which will be explained later. If x(t) contains a sinusoidal component Am cos 2πfmt, multiplication by a sinusoidal carrier wave cos 2πfct with fc >> fm yields

1940_What is Frequency Translation and Product Modulation1.png

Waveforms of the signal, the carrier wave, and the product, as well as their respective line spectra, are shown in Figure. Notice that the low frequency fm has been translated to the higher frequencies fc ± fm.

Next, let us consider an arbitrary low-pass signal x(t) with the typical amplitude spectrum of Figure. The amplitude spectrum of the modulated wave xc(t) will now have two sidebands (lower and upper sidebands), each of width W on either side of fc, as illustrated in Figure. Thus, we have a signal that can be transmitted over a bandpass system with a minimum bandwidth of which is twice the bandwidth of the modulating signal. This process is then known as double-side band modulation (DSB). Either the lower or the upper sidebandmay be removed by filtering so as to obtain single-sidebandmodulation (SSB) with B=W, if the bandwidth needs to be conserved.

1894_What is Frequency Translation and Product Modulation2.png

By choosing the carrier frequency fc at a value where the system has favorable characteristics, the frequency translation by product modulation helps in minimizing the distortion and other problems in system design.


Related Discussions:- What is frequency translation and product modulation

Control systems, Hi, What is the time response for a closed loop transfer f...

Hi, What is the time response for a closed loop transfer function:H(s) = 10/(s^2 +s +1) to delta function input?

What do you mean by conductors and insulators, Q. What do you mean by Condu...

Q. What do you mean by Conductors and Insulators? In order to put charge in motion so that it becomes an electric current, one must provide a path through which it can flow eas

Show the complement representation, Q. Show the Complement Representation? ...

Q. Show the Complement Representation?   There are two types of complements for each number system. r's and (r-1)'s complement ex.             decimal

Why do we cascade amplifiers, Q. Why do we cascade amplifiers? Why is RC co...

Q. Why do we cascade amplifiers? Why is RC coupling the most widely used coupling between 2 stages of a cascading amplifier? The voltage or power gain or frequency response obt

Chopper configuration - power supplies , Chopper Configuration Choppe...

Chopper Configuration Chopper are classified  in five  different classes according  to their operating capability in particular quadrant. The  current  directions and voltage

Conducting material, #question.classification of conducting material.

#question.classification of conducting material.

What is polymerised resultant of phenol and formaldehyde, Phenol and Formal...

Phenol and Formaldehyde are polymerised to a resultant product known as (A) PVC.                                  (B) bakelite. (C)  Polyester.                        (D)

What does the eu do, Execution Unit receives program instruction codes and ...

Execution Unit receives program instruction codes and data from BIU, implements these instructions and store the result in general registers.

Zener diode, Zener Diode A Zener diode is a sort of diode that allows ...

Zener Diode A Zener diode is a sort of diode that allows current not only in the forward direction such as a normal diode, but as well in the reverse direction if the voltage

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