Pn sequence generator USING MAT LAB
Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
computer science topics
Active In SP
**

Posts: 610
Joined: Jun 2010
#1
22-06-2010, 09:46 PM



.ppt   Pn sequence generator USING MAT LAB.ppt (Size: 1.25 MB / Downloads: 362)

PN SEQUENCE GENERATOR
USING MAT LAB

Presented BY
D.SAI KRISHNA



WHAT IS PN SEQUENCE GENERATOR

Pseudo random Noise sequence generator is a circuit which generates pseudo random noise sequences.
A pseudo- noise sequence is a binary sequence with a noise like wave form that usually generated by means of a Linear feedback shift registers.


Block Diagram Of Linear Feedback Shift Register
WHAT IS LINEAR FEEDBACK SHIFT
REGISTER

A Feedback shift register consists of an ordinary shift register made up of m Flip-Flops .
The flip-flops in the shift register are regulated by a single timing clock.
At each pulse of the clock, the state of each flip-flop is shifted to the next one i.e. the contents of the register is shifted right by one position at each clock cycle.
The feedback from the left most register are XOR- ed together, to give a random sequence.
But this binary sequence is not totally random, because it does repeat after many cycles, thatâ„¢s why it is so called as pseudo random noise sequence generator.


Shift Register Length:

This is often referred to as the degree, and in general, the longer the shift register, the longer the duration of the pn sequence before it repeats.
The combination of taps and their location is often referred to as a polynomial, and expressed as:
P(x)=1+x^2+x^3
Where the leading ˜1™ represents x^0, which is the output of the last register, x^2 is the output of register stage 3 and x^3 the output of XOR.
A maximal sequence for a shift register of length L is referred as m-sequence, and is defined as:
L=2^m-1.


APPLICATIONS :

These pn sequence generators are widely used in Cmos testing process as to generate test patterns.
And also used to generate spreading codes in CDMA,FDMA and PCM.


CMOS TESTING PROCESS

In VLSI designing process we will spend 25% for manufacturing, and 75% for testing.
By detecting a malfunctioning chip at an earlier level, the manufacturing cost may be kept low.
Properties:

In each period of a maximal “ length sequence, the number of 1™s is always one more than the number of 0™s.This property is called as the Balance property.


Example:

101000111101001
Among the runs of 1â„¢s and of 0â„¢s in each period of a maximal-length sequence, one half the runs of each kind are of length one, one fourth are of a length two, one- eighth are of length three, and so on as long as these fractions represent meaningful numbers of runs. This property is called the Run property.
The autocorrelation function of a maximal-length sequence is periodic and binary value. This property is called as correlation property.


PN sequences have single autocorrelation peak, this feature permits the transmission to be asynchronous.



ADVANTAGES AND DISADVANTAGES :
Advantages:

The sequences generated by an LFSR can be nearly random with long periods, which aids in making the spread signal appear noise like.
Easy of implementation.
Output of lfsr is periodic.
For any given size of LFSR, a maximum of different unique m-sequences can be generated .



Disadvantages:

Cross correlation properties are good for more than two users. Thatâ„¢s why we go for gold sequences.
Thank You
Use Search at http://topicideas.net/search.php wisely To Get Information About Project Topic and Seminar ideas with report/source code along pdf and ppt presenaion
Reply

Important Note..!

If you are not satisfied with above reply ,..Please

ASK HERE

So that we will collect data for you and will made reply to the request....OR try below "QUICK REPLY" box to add a reply to this page

Quick Reply
Message
Type your reply to this message here.


Image Verification
Please enter the text contained within the image into the text box below it. This process is used to prevent automated spam bots.
Image Verification
(case insensitive)

Possibly Related Threads...
Thread Author Replies Views Last Post
  Design of microturbine generator by using matlab Simulink for smart grid study tips 0 781 31-08-2013, 04:42 PM
Last Post: study tips
  Doubly-Fed Induction Generator for Variable Speed Wind Energy Conversion Systems pdf study tips 0 346 29-08-2013, 04:30 PM
Last Post: study tips
  ROBUST STABILIZER OF ELECTRIC POWER GENERATOR USING H ∞ WITH POLE PLACEMENT pdf study tips 0 432 02-08-2013, 12:38 PM
Last Post: study tips
  Impulse voltage generator modelling using MATLAB seminar flower 3 1,232 11-06-2013, 09:26 AM
Last Post: study tips
  SCROLLING MESSAGE DISPLAY LAB MANUAL study tips 0 383 08-06-2013, 12:29 PM
Last Post: study tips
  PARITY CHECKER LAB MANUAL study tips 0 256 08-06-2013, 12:29 PM
Last Post: study tips
  SIMPLE ALARM SYSTEM LAB MANUAL study tips 0 302 08-06-2013, 12:28 PM
Last Post: study tips
  Melody generator for greeting cards report study tips 0 256 07-06-2013, 01:57 PM
Last Post: study tips
  Direct torque control of a doubly-fed induction generator of a variable speed wind study tips 0 391 08-05-2013, 04:12 PM
Last Post: study tips
  Design and Implement Bicycle Power Generator House Report study tips 0 437 05-03-2013, 09:59 AM
Last Post: study tips