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mixer - demodulation question

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STOIKOV

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an AM direct-conversion system built with a mixer, is similar to demodulate an AM signal with a diode for recovering the envelope ?

if the mixer's output has IF, it is not a direct-conversion, so the next stage task is to demodulate (recover envelope) ??
 

for direct conversion the am signal is mixed by the carrier so the results will be the info signal with some degradation in the amplitude due tothe phase error between the the am signal and the carrier

a pll circuit can be used to remove the phase error

if the output of the mixer is IF the next stage may be second IF or demodulation am or fm
if am demodulation you can use envelope or direct conversion system or any thing
 

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    STOIKOV

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if mixer's output is an IF , and next stage is a demodulator then what frequency should be the IF or its components in order to recover the information ?
 

if you are using envelope detector you can use any freq for the IF
but you have to adjust the value of the r and c of the envelope detector

if you are using direct conversion use any IF freq but make the frequency of the mixer equal to the IF freq and in phase using a pll circuit

in practical systems the if = 10.7 MHZ or 455K
 

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    STOIKOV

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what kind of signals I may apply in ADS simulation, in order to check the expected output. Maybe an AM signal with specific carrier frequency ??
 

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