What is CDMA how it works?
How CDMA Works. CDMA uses a “spread-spectrum” technique whereby electromagnetic energy is spread to allow for a signal with a wider bandwidth. This approach allows several people on different cell phones to be “multiplexed” over the same channel to share a bandwidth of frequencies.
What is CDMA diagram?
Difference between CDMA and GSM
| Criteria | CDMA |
|---|---|
| Technology | CDMA is based on spread-spectrum technology which makes the optimum use of available bandwidth. |
| Security | CDMA is more secure than GSM. |
| Global reach | CDMA is used in usa and some part of canada and japan. CDMA is used only by 24% of the users worldwide. |
Is CDM digital or analog?
CDM may be defined as a form of multiplexing where the transmitter encodes the signal using a pseudo-random sequence. CDM involves the original digital signal with a spreading code. Guard spaces are realized by using codes with orthogonal codes. In cue of TDM and FDM, channels are isolated by separate .
What is TDM and CDM?
Time Division Multiplexing (TDM) Code Division Multiplexing (CDM) Space Division Multiplexing (SDM)
Is WDM and CDM same?
Conceptually, the difference between the WDM, TDM, and CDM can be understood as follows. The WDM and TDM techniques partition the channel bandwidth or the time slots among users. In contrast, all users share the entire bandwidth and all time slots in a random fashion in the case of CDM.
Can a digital signal be multiplexed with time division multiplexing?
Both analog and digital signals can be multiplexed using time division multiplexing, but its processing technique allows the multiplexing of digital signals conveniently rather than analog one. The figure below shows the block diagram of a TDM system employing both transmitter and receiver section.
How is code division multiple access technology used?
The technology is commonly used in ultra-high-frequency (UHF) cellular telephone systems, bands ranging between the 800-MHz and 1.9-GHz. Code Division Multiple Access system is very different from time and frequency multiplexing. In this system, a user has access to the whole bandwidth for the entire duration.
Why is time division multiplexing ( TDM ) called Pam?
The technique efficiently utilizes the complete channel for data transmission hence sometimes known as PAM/TDM. This is so because a TDM system uses a pulse amplitude modulation. In this modulation technique, each pulse holds some short time duration allowing maximal channel usage.
How are selection lines represented in a multiplexer logic diagram?
Let the input channels are represented by I 0, I 1, I 2, and I 3; and the output is represented by the Y. The selection lines are represented by S 0 and S 1. As you can see clearly a multiplexer logic diagram simply consists of 2 Not Gates, 4 AND Gates, and 1 OR Gate. The outputs of all the AND gates are added using a single OR Gate.