baseband and broadband signalling

[sarahr202]

hi every body.

I have few questions .

1)Can broadband signaling be in digital? for example  fiber can  be used as broadband medium carrying more than one signals such as voice,data in digital.  On the other hand, we can also see cable Internet  also use a broadband signaling as more than one signal such tv channels are carried by the co-axial cable. So is it not necessary that broadband signaling will always be in analog form. am i correct?

2) can baseband signaling be in analog form?  or it always in digital form as is the case with Ethernet ?

thanks and have a good weekend.

[narendrakumar1987in]

I too have the same doubt. Can someone clarify please.

Rgds

Narendrakumar B

[Ganesh Hariharan · Accepted solution]

hi every body.
I have few questions .
1)Can
broadband signaling be in digital? for example  fiber can  be used as
broadband medium carrying more than one signals such as voice,data in
digital.  On the other hand, we can also see cable Internet  also use a
broadband signaling as more than one signal such tv channels are
carried by the co-axial cable. So is it not necessary that broadband
signaling will always be in analog form. am i correct?
2) can baseband signaling be in analog form?  or it always in digital form as is the case with Ethernet ?
thanks and have a good weekend.

Hi Sarah,

For your query baseband can carry both analog and digital signal where as broadband carries analog signal and another difference is Baseband signal  is like point to point communication and broadband to is point to multipoint communication.Baseband signals  will carry single signal in a medium but Broadband can carry multisignals through single medium with shared bandwidth.

Hope to Help !!

Ganesh.H

If helpful do rate the post

[sarahr202]

In broadband, total bandwidth is sliced among different channels.  For example  cable tv, each station is allocated a slice of total bandwidth.  In cable we see these channels  are analog.  But do they have to be?   For example in fiber optic medium., we do the same thing  , transmitting multiple channels( such as voice,data,video)  at the same time but in digital form.    So i am observing that broadband medium    can carry multiple analog  as well as digital signals as is the case with fiber.     The question remains if i am correct in my observation.

Second issue  is baseband does not mean point to point  communication.    Point to point  communication means either we have dedicated link or virtual link between two nodes.   As we know  ethernet is shared medium,  for example  10base-T  using hub is good example   where base signaling is used on a shared medium.

Thanks

[Ganesh Hariharan · Accepted solution]

In broadband, total bandwidth is
sliced among different channels.  For example  cable tv, each station
is allocated a slice of total bandwidth.  In cable we see these
channels  are analog.  But do they have to be?   For example in fiber
optic medium., we do the same thing  , transmitting multiple channels(
such as voice,data,video)  at the same time but in digital form.    So
i am observing that broadband medium    can carry multiple analog  as
well as digital signals as is the case with fiber.     The question
remains if i am correct in my observation.
Second
issue  is baseband does not mean point to point  communication.   
Point to point  communication means either we have dedicated link or
virtual link between two nodes.   As we know  ethernet is shared
medium,  for example  10base-T  using hub is good example   where base
signaling is used on a shared medium.
Thanks

Baseband devotes the entire capacity of the medium to one communication channel. Broadband enables two or more communication channels to share the bandwidth of the communications medium. Baseband is the most common mode of operation. Most LANs function in baseband mode, for example. Baseband signaling can be accomplished with both analog and digital signals. Although you might not realize it, you have a great deal of experience with broadband transmissions. Consider, for example, that the TV cable coming into your house from an antenna or a cable provider is a broadband medium. Many television signals can share the bandwidth of the cable because each signal is modulated using a separately assigned frequency. You can use the television tuner to choose the channel you want to watch by selecting its frequency. This technique of dividing bandwidth into frequency bands is called 'Frequency-division Multiplexing' (FDM) and works only with analog signals. Another technique, called 'Time-division Multiplexing' (TDM), supports digital signals.

Yes you are right in broadband  signalling divides the network medium into multiple channels, allowing several signals to traverse the medium at the same time.

Baseband signaling only sends a single signal over the cable. This type of signaling is typically used in Ethernet networks, with the exception of 10Broad3 standard (rarely used). Baseband uses very simple transceiver devices that send and receive signals on a cable. The simplicity behind baseband signaling is that only three states need to be distinquished: one, zero and idle.

Broadband transceivers are much more complex because they must be able to distinquish those same states, but on multiple channels within the same cable. Because of its simplicity, baseband signaling is used on most Ethernet networks.

Hope to Help !!

Ganesh.H

[Giuseppe Larosa · Accepted solution]

Hello Ganesh,

>> This technique of dividing bandwidth into frequency bands is called 'Frequency-division Multiplexing' (FDM) and works only with analog signals. Another technique, called 'Time-division Multiplexing' (TDM), supports digital signals.

this is not generally true: forms of FDM are possible also for digital signals for example in DVB-T that is under introduction in some european countries like Italy.

Also in Hybrid Fiber networks like cable networks is possible to multiplex in frequency analog signals ( AM or FM TV channels) and data services like internet access.

In digital demodulation after frequency translation (to go back to baseband like in a TV or radio tuner) the receiver eestimates one or more digits over a symbol interval.

in analog demodulation after frequency translation (to go back to baseband like in a TV or radio tuner) the modulating waveform over time is the result of the operation.

All these modulations and demodulations are modeled with maths operations like Fourier transformation  or Z transformation and are implemented in DSPs.

Hope to help

Giuseppe

[Ganesh Hariharan]

Hello Ganesh,
>>
This technique of dividing bandwidth into frequency bands is called
'Frequency-division Multiplexing' (FDM) and works only with analog
signals. Another technique, called 'Time-division Multiplexing' (TDM),
supports digital signals.
this
is not generally true: forms of FDM are possible also for digital
signals for example in DVB-T that is under introduction in some
european countries like Italy.
Also
in Hybrid Fiber networks like cable networks is possible to multiplex
in frequency analog signals ( AM or FM TV channels) and data services
like internet access.
In
digital demodulation after frequency translation (to go back to
baseband like in a TV or radio tuner) the receiver eestimates one or
more digits over a symbol interval.
in
analog demodulation after frequency translation (to go back to baseband
like in a TV or radio tuner) the modulating waveform over time is the
result of the operation.
All
these modulations and demodulations are modeled with maths operations
like Fourier transformation  or Z transformation and are implemented in
DSPs. 
Hope to help
Giuseppe

Hello Giuseppe,

I was not aware of the fact about FDM and TDM in that much details anyhow thanks for providing the example of DVB-T.

Ganesh.H