application of active bandpass filter

Discussion in 'Wireless & RF Design' started by hytee, Mar 31, 2009.

  1. hytee

    Thread Starter New Member

    Mar 31, 2009
    3
    0
    Hi, cloud anybody tell me about the application of active bandpass filter which has lower and upper cutoff frequency at 300HZ and 3000HZ respectively in our real life?
    Tha:)nk.(urgent)
     
    Last edited: Mar 31, 2009
  2. t_n_k

    AAC Fanatic!

    Mar 6, 2009
    5,448
    782
    Do you want to know about the specific application of a filter with these characteristics or do you want to gain an understanding of how to design such a filter?

    Suggestions:

    Google "active bandpass filter design" ...etc

    If you are interested in the circuit designs & simulation then you could try this free down-loadable filter design program....

    http://focus.ti.com/docs/toolsw/folders/print/filterpro.html

    or this on-line design tool ....

    http://www.analog.com/en/design-too...ign-sim-tool/Filter_Wizard/resources/fca.html
     
  3. flat5

    Active Member

    Nov 13, 2008
    403
    17
    One such use would be a radio play in which you need the sound of someone talking on the telephone.
     
  4. Darren Holdstock

    Active Member

    Feb 10, 2009
    262
    11
    Sounds like something bandwidth limited for speech - most likely a telephone or an intercom. Most common bandpass filters are restricted to f_high < 2f_low (very roughly), so it would be usual to make this bandpass filter from a highpass followed by a lowpass.
     
  5. hytee

    Thread Starter New Member

    Mar 31, 2009
    3
    0
    Hi, Thanks a lot for your guys' suggestions. Actually i want to know about the specific application of bandpass filter (active or passive) with these kind of characteristics. Cloud u help me? thanks
     
  6. Darren Holdstock

    Active Member

    Feb 10, 2009
    262
    11
    hytee, I think you need to ask the question in a different way; it's not clear what you need. It's just a language barrier - your English is better than my Malaysian. Are you asking whether a passive or active filter is best for the job, or are you looking for working circuits?
     
  7. gotumal

    Active Member

    Mar 24, 2008
    99
    0
    The application is in the telephony, or any voice network. Since the vocal frequencies lie between 0.3. to 3.4kHz, these filters are used to remove unwanted noise.

    P.S. This question was asked for my viva, and I answered correct! :)
     
  8. KL7AJ

    AAC Fanatic!

    Nov 4, 2008
    2,040
    287
    That would be the audio bandwidth of a typical single sideband transmitter as well. (Which translates to the same R.F. bandwidth, if everything is working as it should. :) )
     
  9. RAH1379

    Well-Known Member

    Dec 13, 2005
    69
    1
    Those frequencies are where most of the information is contained in the human voice, the filter will let the voice through while stopping other noise with higher or lower frequencies. it is a common filter used in voice communications.
     
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