Skip to main content

Baseband signal g(t) Modulation Concept and Different Modulation Scheme with equations

Modulation is used to modulate baseband signal. Basically it is a technique used to generate a strong signal from a weak signal with help of a transporter signal known as carrier signal.

A baseband signal is main source of any signal. It can be a sinusoidal wave or discrete pulse. In communication a baseband signal need to traverse long distance, but it become weak with respect to distance so that we need to add a carrier which carry the base band signal and send baseband signal to destination.

A baseband signal pass through a modulator with carrier frequency then transmission starts, on other side demodulator demodulate signal and receive the original signal.
 
Practical example: If we through a paper it will traverse some distance but if we through it along with a stone it will traverse more distance. Here paper is baseband signal and stone is carrier.

Modulation concept
Basic signal modulation concept with carrier frequency

There are three basic type of Modulation schemes which are describe below:

1. Analogue Modulation
2. Digital Modulation
3. Pulse Modulation

Analogue Modulation:

This modulation scheme works with analogue signal (continuous signal varies in time) to traverse forward.

AM:Amplitude Modulation
FM:Frequency Modulation
PM:Phase Modulation


Digital Modulation:

This modulation scheme works with digital signal (discrete signal)

ASK:Amplitude Shift Keying
FSK:Frequency Shift Keying
PSK:Phase Shift Keying

Pulse Modulation:

This modulation scheme works with pulse wave.

PAM:Pulse Amplitude Modulation
PFM:Pulse Frequency Modulation
PPM:Pulse Position Modulation
PWM:Pulse Width Modulation
Modulation Schemes
Different Modulation Schemes

Amplitude Modulation Equation for Baseband Signal in frequency domain is:-

S(t)=[1+ mg(t)]c(t)
     =A[1+ mg(t)] cos(wct)
            A = Amplitude
            m = Modulation Index
            g(t) = Baseband Signal
            wc =  Angular Frequency (rad/sec)

Frequency Modulation Equation:
s(t) = A cos Ø(i)t

Where Ø(i)t is instantaneous phase

Labels:

Comments

Post a Comment

Popular posts from this blog

Facebook timeline recent activity and post disappeared

Facebook Timeline gives our profile a new graphical look. It also launches many new features. Activity log is one of them where we will find all of our recent activities on profile, example: Any “Like” on own or others post, comments, status update, add new photos, invites someone to add group, add albums, send friend request etc. But sometimes we face problem with disappear recent activity from Facebook timeline or wall post from profile. This problem is one of the common problems in new feature. It may happen in two stage of your account.  - When your account transfer from old wall view to Timeline or New profile in Timeline. - Another stage is for existing Timeline account, where recent activity disappears without any specific reason. The first case we can handle very easily. It basically happen due to transfer and the solution depends on visibility of your post or activity like (Public, Friends and Custom). Now set your visibility settings from privacy setting or directly fro
21 comments
Read more

Brief and Examples on Simplex, Half-Duplex, Full-Duplex Transmission

In data communication, there are three types of communication styles; they are Simplex, Half-Duplex and Full-Duplex. Here we discuss about their characteristics with examples. Simplex: In this communication style data can send only and basically it is one way or uni-direction communication. This type of communication is not widely used for transmit trusted data because it can not send any error or control signal to sender terminal. This style of communication is vastly used in Radio and TV where we can see and hear or receive data only but we can not send any information data by the same channel. Half-Duplex: Half-Duplex is another type of communication style where data can and send and receive but not at the same time. In this communication type, if data is send from one end, then we can not send data from another that means communication establish in one direction.  This communication vastly used in walkie-talkie, intercom, string phone etc. The practical exam
Post a Comment
Read more

Limit user from changing system time and date in Windows OS

Most of us do not concern with system date and time. But it is one of most important factor in all operating system because when all software need system date and time for any update whether it is server end or end user end. Here we are talking about the importance of system date and time and procedure to restrict user from changing system date and time from front end or user end. So we need to keep it intact without any unnecessary changes. If any user except can have the right to change date and time from user end, then it will fall us in deep trouble specially when we run software which take entry time input from end user end. There are also many software mechanisms which does not allow date and time difference to start up.  For above reason we do not give user access to change date and time from user end. We can limit the user from this feature. Here I show steps how we can control user access in windows operating systems. Steps to follow:- 1. Go to "Start menu" an
1 comment
Read more