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Question
What is meant by pre-emphasis and de-emphasis?
 Question Submitted By :: Electronics-Communications
I also faced this Question!!     Answer Posted By  
 
Answer
# 1
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 ?    289 Yes 29 No
Dinesh Anand
 
Answer
# 2
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 ?    141 Yes 73 No
Kamalakannan.l
 
 
 
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 = 75s. 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 ?    80 Yes 20 No
Debopam Banerjee
 
Answer
# 4
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 ?    58 Yes 5 No
Mandeep Kaur Maan
 
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 9 No
Harimohan K. Bhagwane
 
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 ?    28 Yes 6 No
U.p.pavan Kumar Yadav
 
Answer
# 7
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 = 75s. 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 10 No
Disney_snoopy
 
Answer
# 8
pre- emphasis boosting of amplitude of higher
frequency signal.






de- reducing the amplitude of higher frequency componant
 
Is This Answer Correct ?    8 Yes 1 No
Nidhant
 
Answer
# 9
preemphasis is the process of boosting the information signal in order to reduce the noise ocuurance .
eg:we can use high pass RC circuit,
Deemphasis is the process in which the boosted signal is brought down to normal information signal present at initial.
eg:we can use low pass RC circuit.
 
Is This Answer Correct ?    6 Yes 1 No
Samyukthajakkam
 
Answer
# 10
pre emphasis :Boosting of the high freuencies, in
accordance with a pre-arranged curve is pre emphasis.

de emphasis :The compensation at the receiver is de
emphasis
 
Is This Answer Correct ?    7 Yes 3 No
Shravya
 

 
 
 
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