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Gain of the system of amplifiers

  1. Jun 16, 2005 #1
    I need help with the two questions below please because i just don't understand it !!!1

    1. A signal processing system consists of a preamplifier, an amplifier and a filter connected in series. At a given frequency the preamplifier and the amplifier have gains of 12 dB and 31 dB respectively, while the input and output voltages of the filter are 7.0 v and 0.35v respectively. Calculate the overall gain of the system at that frequency.

    2. A rock band produces music with a bandwidth from 30Hz to 20kHz. If the music is amplified through a system with the following bandwidths what range of frequencies will be heard by the audience.

    Microphones (10Hz to 12khz), Amplifiers (45Hz to 16kHz), Loudspeakers (50Hz to 14kHz).

    Thanks !!!!
  2. jcsd
  3. Jun 16, 2005 #2
    I think i have cracked it !!!

    1. voltage gain/loss = 20log V1/V2 = 20log (0.35/7) = - 26dB

    And the overall gain is 12dB - 26dB + 31dB = 17dB

    2. The audience would hear around 50Hz - 14kHz.

    I don't know if my answers are corrected, if it isn't can u please corrected me .

    :approve: :approve: :approve: :approve: :approve:
  4. Jun 16, 2005 #3


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    #1 looks good to me. #2 does not. How is a 14kHz signal going to get to the speakers?
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