How to design telephone amplifier with op amp and filters

Discussion in 'Homework Help' started by kungfupanda1947, Dec 2, 2009.

  1. kungfupanda1947

    Thread Starter New Member

    Dec 2, 2009
    3
    0
    Use op amp and filter circuits to build a telephone amplifier from 300 to 4k Hz with again of 50 (or -50). Check points: 1) -3dB frequencies at 300 Hz and 4 kHz. 2) voltage gain of 50 in mid-band.

    Please help to solve the problem above. I have got a start and think that to design this I have to cascade high pass and low pass to form band pass to get desired frequencies and then cascade it to a op-amp(ua741) to get gain. I kind of know the equations but still please help me solve the problem and let me know if my start is a correct start or not.
     
  2. mik3

    Senior Member

    Feb 4, 2008
    4,846
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  3. Audioguru

    New Member

    Dec 20, 2007
    9,411
    896
    You need highpass and lowpass filters, not a bandpass filter.
    The bandpass filter is used for a narrow range of frequencies.

    Use butterworth second-order or third-order Sallen and Key filter circuits for sharp cutoffs.
     
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