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Pre-emphasis and DE-emphasis circuits?

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7rots51

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pre emphasis circuit

what is Pre-emphasis and DE-emphasis circuits in FM voice radio?

what is do?

Please send information.
 

Azulykit

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pre-emphasis

Pre-emphasis shapes a signal before it is sent and post-emphasis shapes it after it is received. The idea is to compensate for distortions that the transmission channel may/will introduce.

Radars also sometimes use this to spread a pulse and thus transmit more power. Then on reception compress the pulse to improve range resolution.
 

7rots51

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site:edaboard.com pre-emphasis

please give me some OPAMP circuit for pre-emphasis and de-emphasis.
 

Borber

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pre emphasis and de emphasis

Deemphasis circuit is trivial. Use current generator which supply parallel RC whose time constant is 50us or 75us regarding what you need.
 

disney_snoopy

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any idea on matlab source code of this pre-emphasis FIR filter?

I have 1 coding in my hand but the number of order is too high!!! i doesnt want the number of order higher than 32.

Any idea?
 

zingade_se

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Re: pre emphasis and de emphasis

[I need pre emphasis and de emphasis circuits using opamp
 

dinosaur078

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Re: pre emphasis and de emphasis

[I need pre emphasis and de emphasis circuits using opamp

dear you all

in PCIe gen 3, why do we need preshoot technique ?

thank you in advance
 

SunnySkyguy

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Since noise is constant per unit bandwidth , noise is thus greater with higher center frequency
i.e. bass 50 ~500Hz is lower bandwidth than 500~15kHz so the treble is amplified on transmitter and reduced in receiver so response net is flat.

I recall there is 15dB of pre-emphasis but I forget the breakpoint frequency.
 

dinosaur078

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dear sunny ?
could you explain more about preshoot in detail ?
thanks
 

SunnySkyguy

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visualize treble control set to 15dB gain for Transmitter (Tx) and Receiver treble set to -15 dB before the equalizer.

This is pre-emphasis..(Tx) and de-emphasis (Rx)

not preshoot.
 

dinosaur078

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i think there is a different view of PRESHOOT.
this is its definition :
" Preshoot is a new feature designed to improve the signal in the following bit time by boosting the voltage in the current bit time"

why it can improve signal ?

pls
 

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