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- 5th February 2007, 18:20 #1

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## difference between frequency and bandwidth

Hey guys does anybody knows Difference between Analog and Digital BandWidth..

In relation with Analog and Digital circuit design...

- 5th February 2007, 18:20

- 6th February 2007, 00:41 #2
## analog and digital bandwidth

At here there are some useful information for you :

*en.wikipedia.org/wiki/Bandwidth*

- 6th February 2007, 00:41

- 6th February 2007, 05:04 #3

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## comparison of analog &digital bandwidth

but it is not still clear that while designing any analog or digital ckt how it will be used???

- 6th February 2007, 05:04

- 6th February 2007, 10:19 #4

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## analog digital bandwidth

In analog design the concept of bandwidth as we

all know is related to the frequency at which the

output will drops it's power by 1/2 the maximum.

In digital the bandwidth is nothing but the bit rate

possible through the channel .. it is wrong terminology

to use but the comp science ppl can't help stealing

analog ppl's vocab .. anyway the maximum bits

per second is related to the analog bandwidth by

the very famous relation given by Shanon .. i.e.

C = BW * log_2 ( 1 + S/N)

Where

C = Channel capacity in Bits per secodn

BW= Analog bw available in channel

S/N = Signal to Noise ration

but sill the bandwidth in Digital depends on several

things like signal format like RZ, NRZ and Manchester etc..

- 6th February 2007, 13:56 #5

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## digital vs analog bandwidth

Analog bandwidth is the maximum sinusoidal frequency of the analog signal the circuit works with.

But digital bandwidth of a circuit is different.

Digital bandwidth of a circuit is is less than analog bandwidth because digital signals are made of 1 and 0 values and these are sqaure wave signals. If you plot the the frequency spectrum of the square wave the maximum frequency content in the signal is more than the frequency of the square wave.

For example the fourier transform of a 1MHz clock signal contains harmonics at much higher frequencies. Therefore inorder to work at clock frequecny of 1MHz a circuit bandwidth has to be more than 1MHz.

But in analog circuit if the highest frequency of the signal is 1MHZ then your circuit BW needs to be only 1MHz.

There is a relation for the digital bandwidth of a circuit and clock frequency.

I forget now BW = 2.85fclock i think.

Hope this helps

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