how to make the 5 MHz sine wave generator

Discussion in 'Homework Help' started by enur, Sep 23, 2008.

  1. enur

    Thread Starter Member

    Sep 13, 2008
    13
    0
    hi to all,

    I need 5 MHz sine wave generator (circuit or IC) for my application. Unfortunately, I didn't find it in internet. Most of them is below 1MHz.

    could you help me?

    thanks before
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    How good must the sine wave be? It's fairly easy to knock the edges off a 5 MHz square wave with an RC filter.
     
  3. bertus

    Administrator

    Apr 5, 2008
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  4. Wendy

    Moderator

    Mar 24, 2008
    20,765
    2,536
    5Mhz is easily within the range of LC filters, that is, you don't need huge values to acomplish the design. A simple LC filter should do it, if you need extreme purity of the signal, a series resonant followed by a parallel should do it.
     
  5. liitlefan

    New Member

    Sep 24, 2008
    7
    0
    the most straight way:
    what's about crystal oscillator ??
     
  6. enur

    Thread Starter Member

    Sep 13, 2008
    13
    0
    thanks for all response.

    to beenthere : I need as pure as possible. I'll use it to generate the transducer of ultrasound

    to bertus : Based on the page, the clapp and hartley oscillator is just working up to 1.67 MHz. May I know how to increase the workspace of oscillator up to 5 MHz? thanks.

    to Bill_Marsden : I am still confuse what you are saying. I am still beginner on it. May I know the detail? or may be, where I can find the article of it in web?

    to liitlefan : I think the crystal oscillator is square wave (am I false?). May I know How to change it to sinewave?
     
  7. bertus

    Administrator

    Apr 5, 2008
    15,647
    2,346
    Hello,

    There are formulas on the page to calculate the frequency.
    Smaller coils and capacitors will give a higher frequency.
    These oscillators can be used upto 100 Mhz.

    Greetings,
    Bertus
     
  8. Wendy

    Moderator

    Mar 24, 2008
    20,765
    2,536
    This is a simple coil capacitor filter.

    [​IMG]

    It will convert almost any waveform at 5Mhz into a sine wave. Finding the right values is the hard part, and the two coil and two caps don't have to be the same values, as long as they match their counterpart (an LC circuit).

    There are a lot of oscillators, including crystal oscillators, that produce less than perfect wave forms. This circuit will usually clean them up.

    At this point you will need to decide on the power you intend to produce. This should handle a square wave pretty well.
     
    Last edited: Sep 25, 2008
  9. enur

    Thread Starter Member

    Sep 13, 2008
    13
    0
    Thank's a lot to bertus and Bill_Marsden.
    I'll try it. :)
     
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