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

Develop the equation of motion, Aloudspeaker is a common electrochemical tr...

Aloudspeaker is a common electrochemical transducer in which vibration is caused by changes in the input current to a coil which, in turn, is coupled to a magnetic structure that c

Resistance, if the sheet resistance of a tin oxide is 100 ohms, what is the...

if the sheet resistance of a tin oxide is 100 ohms, what is the thickness of the oxide layer?

Complier -high level language , Complier-High Level language It al...

Complier-High Level language It also  translates the  whole  high  level  program  into object  program if it does not  have any  syntax error. The disadvantage of the  in

Superposition theroem, what are the limitations of superposition theroem

what are the limitations of superposition theroem

Determine the speed of prime mover of the generator, A synchronous generato...

A synchronous generator has a rotor with six poles and operates at 60 Hz. (a) Determine the speed of prime mover of the generator. (b) Repeat part (a) if the generator has 12

Give the significance of sim and rim instruction, Give the significance of ...

Give the significance of SIM and RIM instruction available in 8085. Instruction SIM: Set Interrupt Mask. This is a 1 byte instruction and can be used three dissimilar functio

Develop an analog computer simulation diagram, Q. Develop an analog compute...

Q. Develop an analog computer simulation diagram to solve the differential equation with y(0) = 2 and ? y(0) = 0.

Explain sahf instructions in 8086 family, Explain SAHF instructions in 80...

Explain SAHF instructions in 8086 family with example and their effect on flag. SAHF: Store AH register in flag register, this is an instruction utilized to store the data i

Examine the features of a typical pc motherboard, Q. Examine the features o...

Q. Examine the features of a typical PC motherboard? The purpose of this experiment is to examine the features of a typical PC motherboard, including: CPU and co-process

Digital, #quesFind a minimum two level, multiple-output AND-OR gate circuit...

#quesFind a minimum two level, multiple-output AND-OR gate circuit to realize these functions (eight gates minimum). F1(a,b,c,d) =Sm(10,11,12,15) +D (4,8,14) F2(a,b,c,d) =Sm(4,11

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