Sequential (152) binding CDMA

https://johnchihau.blogspot.com/2026/04/john-have-look.html?m=1

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Ref: https://johnchihau.blogspot.com/2026/05/httpschihaukam_01311378352.html?m=1

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John : These 2 articles mention about the architecture of "Write lines". You might have a look first. 

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1) https://kamchihau.blogspot.com/2022/08/heat-expand-cold-shrink.html?m=1 . 

2) https://kamchihau.blogspot.com/2022/08/angle-effect-in-optical-fiber.html?m=1 .

Me: Ok.

John : Here're 3 type of multiple access.  They are CDMA, TDMA and FDMA. Today,  we focus on CDMA.

Me: Ok.

John : CDMA stand for code division of multiple access. 

Me: Ok.

John: See the Picture above. During 1 up cycle of the Clock line of the transmitter, the transmitter send to 4 users the same signal. The same signal is 0.0.0.0.

Me: That mean,  this signal has 4 carrier wave.These 4 carrier wave refer to digital signals of 0.0.0.0.

John : Yes, the picture above shows it to you clearly.  Note: The Clock line use a delayed circuit. 

Me: In another words,  the clock line only receive a signal of 1.

John: True. However,  the register is different.  There's no delayed circuit at the register.  As a result,  during 1 up cycle,  the register receive 4 bits. They are 0.0.0.0.

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Me: However,  here's a problem.  If 4 users receive the same code (0.0.0.0), it makes no difference. 

John : You are wrong.  Each users has his own unique ID. For example, 

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User 1 ID. 0.0.0.0

User 2 ID. 0.0.0.1

User 3 ID. 0.0.1.1

User 4 ID. 0.1.1.1

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John : After the Xor gate,  indeed,  Each User receive a different Value.

Me: After the Xor gate,  User 1 receive a value of 0. And, User 2 receive a value of 1.

John : Correct.