ERROR IN OUTPUT OF XOR LOGIC SYSTEM

[vipul]

HI ALL..
AS WE ALL KNOW THE FOLLOWING LOGICAL EXPRESSIONS:

A XOR B= C
C XOR B= A

I HAVE TRIED TO OBTAIN A AFTER CONNECTING TWO XOR (OPTICAL XOR DESIGNED USING SOA)IN SERIES WITH APPROPRIATE INPUTS AS SHOWN IN ATTACHMENT. BUT I AM NOT GETTING CORRECT VALUE OF A.HOWEVER I AM ABLE TO GET OUPTUT C (FIRST EQUATION OUTPUT)WHICH IS IS EXACT VALUE OF A XOR B (CAN BE SEEN IN OSCILLOSCOPE) .CAN ANY BODY POINT OUT THE ERROR.
WAITING FOR RESPONSE EAGERLY….

[Damian Marek]

The reason why this is happening is because the C signal is experiencing a delay. Look at the attached pic and you will see that the RED signal is delayed by 3 bit periods. If you introduce a time delay in the second signal the output should be resolved. (Use the Time Delay component in the Passives library).

Attachments:

1. 

   CompareXOR.png
   

[vipul]

THANKS DAMIAN FOR YOUR HELP.YOU GUYS ARE DOING GREAT JOB!!!!

[siva rama krishna]

Hi Damian,
From the attached image i found that C signl(red line) is delayed by 5 bit periods w.r.t origin,and another signal B is delayed by 3 bit periods. So delay between them is 2 bit periods.

I got correct output when i run the simulation with 2 bit periods delay.

I am attaching my output image.

If i am wrong please rectify me.

Attachments:

1. 

   complete-xor-gate.png
   

[vipul]

YA SIVA U ARE RIGHT.CAN U ATTACH THE PROJECT FILE WITH CORRECT DELAY FOR ME PLEASE.

[siva rama krishna]

Hi vipul,
just add time delay element after optical gaussian pulse generator( in B signal) and set delay as 2 bit periods means 2*(1/Bit rate).
Please see the attached image.

Attachments:

1. 

   complete-xor-gate_delay-element.png
   

[Author]

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