Classification of Signals

1. Continuous and Discrete Time Signals (CTS & DTS)
2. Periodic and aperiodic Signals
3. Deterministic and Random Signals
4. Symmetric (Even) and anti-symmetric (odd) Signals
5. Energy and Power Signals
6. Causal and non Causal Signals.........

Standard Signals or Basic Signals

The standard signals or basic signals are generated in Labs for analyzing the system response.
1. Impulse Signals.
2. Step Signals.
3. Ramp Signals
4. Parabolic Signals
5. Rectangular (Gate) Signals.
6. Triangular Signals
7. Signum Signals
8. Sinc Signals
9. Sinusoidal Signals
10. Exponential Signals

Continuous Time and Discrete Time signals

Signal specified for every value of time 't' is called continuous time signal and is denoted by x(t)

Signal represented for discrete value of time is discrete time signals and is denoted by x[n]

Signals

1. Signal is a physical phenomenon that carries information
2. A function of one or more independent variables which contains some information is called a signal
3. A signal is formally defined as a function of one or more variables that conveys information on the nature of a physical phenomenon

NPTEL Lecture series

This link contains useful lecture series.
http://nptel.iitm.ac.in/courses.php

Signal Processing Research Areas

• Image and Video Compression and Coding
• Speech Coding
• Speech Recognition
• Speaker Verification
• Pattern Recognition
• Communications Signal Processing
• Channel Equalization
• Echo Cancellation
• Array Signal Processing
• Noise Cancellation
• Filter Design and Structures
• Fast Algorithms
• Time-Frequency Signal Analysis
• Multirate Filtering and Filter Banks
• Signal Reconstruction
• Adaptive Filters
• Nonlinear Signals and Systems
• Spectral Analysis
• Statistical Modeling
• Parameter Estimation
• System Identification

Signal Processing Research Areas

I. Image Processing:
 Image processing is any form of signal processing for which the input is an image, such as a photograph or video frame; the output of image processing may be either an image or, a set of characteristics or parameters related to the image. Most image-processing techniques involve treating the image as a two-dimensional signal and applying standard signal-processing techniques to it. Image Processing areas are:
1. Face Recognition
2. Finger Print Recognition
3. Iris Recognition.
4. Gesture Recognition