analog filter

Discussion in 'Homework Help' started by aya, Dec 4, 2006.

  1. aya

    Thread Starter Member

    Nov 30, 2006
    14
    0
    the question is:explain how the attenuation of passband affects to frequency scaling in:a) Butterworth B) Chebychev C)inverse Chebychev


    and what is "vector error" and SAW-filter?What are the different types of SAW-filter?


    thanks in advance
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    Hi,

    Can't make out what you are asking about passband attenuation. Look up some response plots to see the different filter frequency responses.

    Follow the link - http://en.wikipedia.org/wiki/Electronic_filter for the surface acoustic wave filters.
     
  3. Dave

    Retired Moderator

    Nov 17, 2003
    6,960
    143
    I too am struggling to full understand your query relating to passband attenuation and frequency scaling.

    Chapter 20 of Steve Smith's book may be of interest for background reading.

    Dave
     
  4. aya

    Thread Starter Member

    Nov 30, 2006
    14
    0
    that's the exact words from my past year paper!! how could i pass it .......
     
  5. Papabravo

    Expert

    Feb 24, 2006
    9,905
    1,723
    The professor and the University are substandard when it comes to English and/or Electronics. It probably just seems that way from here, and you asked the question.
     
  6. farmosh203

    Member

    Nov 26, 2006
    20
    0
    My teachers slides say:

    "Butterworth - flat response in the passband and acceptable roll-off"

    "Chevyshev - steeper roll-off but exhibits passband ripple (making it unsuitable for audio systems)"
     
  7. Papabravo

    Expert

    Feb 24, 2006
    9,905
    1,723
    OK That's all true so let's get back to your original question. Having some context makes it easier to interpret the question. In the future it may be haelpful to restate them one at a time in simple declarative sentences.

    For example:

    Why is there ripple in the passband of a Chebychev filter?
    Why does a Butterworth filter have a shallow rolloff?

    Get the idea?

    The answers to most of these questions will be:

    It is the arangement of reactive elements and the relative values that produce a certain response. It is the actual value of the components which scales the frequency to the desired cutoff or corner frequency.

    Does that help?
     
  8. beck

    Member

    Nov 27, 2006
    26
    0
    scaling is done so that the normalized values of the components of the filter are converted to practical values. (for eg capacitor and inductor)
    let me point out here that dimensionless parameters such as attenuation and gain is never scaled.
    so the answer to your question would be
    NO EFFECT, be it butterworth, chebyshev,elliptical or cauer,inverse chebyshev
    or whaterver filter.
     
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