How speech is transmitted in digital switching environment, Electrical Engineering

Assignment Help:

Q. How speech is transmitted in digital switching environment by using PCM/TDM?

Ans:

A digital carrier system is a communications system which uses digital pulses instead of analogue  signals  to  encode  information.  Figureshows  the  block  diagram  for  a digital  carrier  system.  This  digital  carrier  system T1  employs PCM-encoded  samples from  24  voice  band  channels  for  transmission  over  an optical  fibre  transmission  line  or single  metallic  wire  pair.  Every voice-band channel  has  a  band  width  of about 300 Hz to 3000 Hz. Again, multiplexer is simply a digital switch with  24  independent  inputs  and  one  time  division  multiplexed  output.  PCM output  signals  from  24  voice-band  channels  are  sequentially  selected  and connected through multiplexer to transmission line.

When  a  T1  carrier  system,  D-type  (digital)  channel  banks  perform  sampling, multiplexing  and  encoding  of  24  voice-band  channels,   every channel  comprise an eight-bit PCM code and is sampled 8000 times a second. Every channel is sampled at the same rate. Figuredemonstrates the channel sampling sequence for a 24-channel T1 digital carrier system. As the Figureillustrates each channel is sampled once each frame though not at the same instance. Every channel's sample is offset from previous channel's sample by  1/24  of  the  total  frame  time.  Hence  one  64-kbps  PCM-encoded  sample  is transmitted for every voice-band channel during each frame (a frame time of 1/8000 = 125 µs). Afterwards, an extra bit (known as the framing bit) is added to every frame. Framing  bit  occurs  once  per  frame  (8000-bps  rate)  and  is  recovered  in the receiver, where it's used to maintain frame and sample synchronization between TDM receiver andtransmitter.

837_How speech is transmitted in digital switching environment.png


Related Discussions:- How speech is transmitted in digital switching environment

Lift control unit, You are required to design and document  the hardware de...

You are required to design and document  the hardware design  for a 68HC12D60 based Lift Control Unit (LCU). This design includes  the Input/Output hardware for interfacing with  l

Semiconductors, Charge density In a semiconductor

Charge density In a semiconductor

Determine voltage ratio for the circuit, Q. Determine v o /v i for the ci...

Q. Determine v o /v i for the circuit shown in Figure if the op amps are ideal.

RLC, a 49pf cap,a 50 uH inductor, and a 100 ohms resister are in parallel: ...

a 49pf cap,a 50 uH inductor, and a 100 ohms resister are in parallel: what is the resonance freq? And what is the complex impedance vector at 100MHZ?

Find the minimum sum of products, Given that , f(a,b,c,d,e) = Σm (6,7,9,11,...

Given that , f(a,b,c,d,e) = Σm (6,7,9,11,12,13,16,17,18,20,21,23,25,28) using a Karnaugh map. (i) Find the essential prime implicants (ii) Find the minimum sum of product

Crm triangle, CRM Triangle The following diagram which is called as CR...

CRM Triangle The following diagram which is called as CRM Triangle. Strategy refers to the whole stand taken through the company. It could selected a defensive posture in t

Logic circuits, : A farmer owns two barns; one north of a creek and the oth...

: A farmer owns two barns; one north of a creek and the other south of the creek. The farmer has a Cabbage, a Goat, and a Wolf. The Farmer needs to put each item in a barn every ni

Balanced score card or bsc, Balanced Score Card or BSC We see in which...

Balanced Score Card or BSC We see in which the traditional model does not reflect the significance of intangible assets, their capturing and measuring mechanism and does not r

Signal and system, You are required to implement below shift system in MATL...

You are required to implement below shift system in MATLAB, t0 is the amount of shift towards left or right. y(t)= x(t-t0) Implement MATLAB code, where shift should be taken as

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd