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yousef_ob

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Posts posted by yousef_ob

  1. hello,
    in the attached equation m(t) is a power signal - not an energy signal. we know that DSB modulation is defined by the equation m(t) cos (2*pi * fc*t). so that the power of this signal is the integration of the sequared equation over the period - i.e power = integration over period of (m(t) cos(2*pi* fc*t)^2. we know that cos^2(wc*t)= .5(1+ cos(2*wc*t))
    then multiply this by m^2(t) and integrate over the period, then the first term in 0.5 * the power of the mudulating signal (m(t)). and the second term is zero i am asking why it is zero. i gonna attatch the equation again

    post-7378-14279142465796_thumb.jpg

  2. hello, plz could anyone solve this for me:
    in a DSB modulation if we assume that the modulating signal is a power signal, why this integration is zero, plz i want the mathemetical prove for the attached equation
    thanx very much

    post-7378-14279142462469_thumb.jpg

  3. HELLO,
    YOU CAN USE THIS METHOD IN FINDING THE TOTAL RESISTANCE SEEN BY A VOLTAGE SOURCE.
    1. AT THE TERMINALS OF THE VOLTAGE SOURCE NAME (a,b), THEN WHEN U FIND ANY RESISTANCE NAME ©, THEN GO ON d,e AND SO ON.
    2. REDRAW THE CCT IN A NEAT FORM BY PUTTING THE LETTERS (a,b,c,d...) THEN SEE WHERE IS THE SERIES AND WHERE IS THE PARALLEL CONFIGURATIONS AND SIMPLFY THE CCT.
    3. DO ANY DELTA-STAR OR STAR-DELTA TRANSFORMATIONS.
    SAY THANX TO ME

  4. HELLO,
    ABOUT YOUR COMMENT, YOU MAY BE WRONG BECAUSE IF YOU USE ONE +VE POWER SUPPLY THEN THE OP-AMP WILL NOT WORK PROPERLY BUT IT WILL SATURATE IN THE -VE REGION AND WE CANT GET A -VE O/P FROM THIS OP-AMP. WE WILL GET THE SAME THING IF WE USE A -VE POWER SUPPLY.
    THANX VERY MUCH

  5. HELLO VISHO,
    ABOUT UR AMPLIFIER CCT U DONT TAKE IN UR ACCOUNTS THE LOADING EFFECTS FROM THE FIRST STAGE TO THE SECOND STAGE.
    U WOULD BETTER USE TRANSISORS OTHER THAN OPAMPS, BECAUSE HERE U NEED ONE POWER SUPPLY BUT IN OP-AMP CCT U NEED TWO POWER SUPPLIES ONE -VE AND THE OTHER +VE.
    BUT THE ADAVANTAGE OF THE OP-AMP ON THE TRANSISTOR THAT THE OP-AMP HAS AN INFINITE INPUT RESISTANCE WHICH IS NOT PRESENT IN THE TRANSISOR SO THE LOADING EFFECTS ARE NEGLECTED.
    IF I WERE U VISHO I WOULD SAY THANX YOUSEF
    BYE

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