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Question
What is meant by pre-emphasis and de-emphasis?
 Question Submitted By :: Meghana
I also faced this Question!!     Rank Answer Posted By  
 
  Re: What is meant by pre-emphasis and de-emphasis?
Answer
# 1
Pre Emphasis

Pre emphasis is nothing but enhanging the message signal
and it is used for Transmission time.

De Emphasis

De Emphasis nothing but the comprese the message signal and
it is used for receiving time.
 
Is This Answer Correct ?    135 Yes 69 No
Kamalakannan.l
 
  Re: What is meant by pre-emphasis and de-emphasis?
Answer
# 2
Pre-emphasis

" Improving the signal to noise ratio by increasing
the magnitude of higher frequency signals with respect
to lower frequency signals"

De-emphasis


" Improving the signal to noise ratio by decreasing
the magnitude of higher frequency signals with respect
to lower frequency signals"
 
Is This Answer Correct ?    280 Yes 29 No
Dinesh Anand
 
 
 
  Re: What is meant by pre-emphasis and de-emphasis?
Answer
# 3
PRE-EMPHASIS :-

In an FM system the higher frequencies contribute more to
the noise than the lower frequencies. Because of this all FM
systems adopt a system of preemphasis where the higher
frequencies are increased in amplitude before being used to
modulate the carrier. The transfer function sketched above
is used for a preemphasis circuit for FM signals in the FM
band. The Time T = 75µs. For FM systems in the FM band m ~ 5
resulting in a S/N improvement of 19dB. With preemphasis
this can be increased by 4dB for a total of 23dB.





DE-EMPHASIS :-

At the receiver the higher frequencies must be deemphasised
in order to get back the origunal baseband signal. The
transfer function of the deemphasis circuit is shown above.
 
Is This Answer Correct ?    78 Yes 19 No
Debopam Banerjee
 
  Re: What is meant by pre-emphasis and de-emphasis?
Answer
# 4
Hi Debopam,

u said that
"The transfer function sketched above
is used for a preemphasis circuit for FM signals in the FM
band. The Time T = 75µs. For FM systems in the FM band m ~ 5
resulting in a S/N improvement of 19dB. With preemphasis
this can be increased by 4dB for a total of 23dB. "

But i cant see and graph here!!!
 
Is This Answer Correct ?    31 Yes 8 No
Disney_snoopy
 
  Re: What is meant by pre-emphasis and de-emphasis?
Answer
# 5
pre emphasis is a process which is used in transmitter side
to boosting the amplitude of higher modulating signal
before modulator.IF we used it after the modulator than
carrier &modulator signal will mixed and it is difficult to
verify which one is the modulating signal.

de emphasis is process which is used in receiver side
to reduced the signal & get their original signal.But it is
used after demodulator ckt.
 
Is This Answer Correct ?    50 Yes 7 No
Harimohan K. Bhagwane
 
  Re: What is meant by pre-emphasis and de-emphasis?
Answer
# 6
pre emphasis:-boosting the higher frequencies before
transmission at the transmiter side is knowns as pre
emphasis

De emphasis:-Reducing the certain frequency in the recevier
side is known as de emphasis
 
Is This Answer Correct ?    26 Yes 5 No
U.p.pavan Kumar Yadav
 
  Re: What is meant by pre-emphasis and de-emphasis?
Answer
# 7
They are two technic’s to transmit a signal without
distortion
 
Is This Answer Correct ?    10 Yes 39 No
Balavenkataraju
 
  Re: What is meant by pre-emphasis and de-emphasis?
Answer
# 8
this is a technic similar to modulation and de modulation
where u can use carrier to the original signal to make it
transmit here we use noise signal for transmitting the
signal with out any interuption
 
Is This Answer Correct ?    8 Yes 14 No
Satishreddy
 
  Re: What is meant by pre-emphasis and de-emphasis?
Answer
# 9
pre emphasis:
It is basically a technique used for FM transmission.
it means to enhance(increase the amplitude of) the higher
frequencies of the modulating signal so as to enhance the
signal to noise ratio ratio. this is done at the time of
transmission. th reason being that the noise affects the
higher frequencies more than the lower frequencies.

de-emphasis:
this is done at the time of recieving the FM signal
it means to lower the amplitude of the higher frequencies
(enhanced at the time of transmission) so that the noise
component that mixes at the transmission tme is cut off and
we recieve a better quality of the signal.
 
Is This Answer Correct ?    53 Yes 3 No
Mandeep Kaur Maan
 
  Re: What is meant by pre-emphasis and de-emphasis?
Answer
# 10
pre
emphasis:
it is nothing but just boosting up of the message
signal similar to the
noisesignal

de-emphasis :it is used to just oposite of pre
emphasis
 
Is This Answer Correct ?    13 Yes 26 No
Vinodh Kumar
 

 
 
 
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