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CaPsLoCkE
Joined: 14 Jan 2008
Posts: 6
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 22 Jan 2008 17:00 matlab spread spectrum clock |
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Hello,
I'm currently working with an electronic product that utilizes SSCG (spread spectrum clock generation).
Can someone explain the concept of this technology. I have a shallow understanding with this.
Thanks!
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haff99
Joined: 10 Mar 2007
Posts: 49
Helped: 6
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22 Jan 2008 17:25 Re: Spread Spectrum Clock Generation |
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| The general gist is you vary the frequency of the clock randomly around its nominal frequency. the energy gets spread out over a wider spectrum. Otherwise you end up with large energy spikes at the base frequency. This is just away to distribute the energy. There are mulitple ways to implement, typically you have some a random oscillator that either changes the charge/discharge current of the oscillator. You can switch in more/less capacitance etc. There are many ways to implement this.
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CaPsLoCkE
Joined: 14 Jan 2008
Posts: 6
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22 Jan 2008 17:36 Re: Spread Spectrum Clock Generation |
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haff99,
You said that there are many ways to implement this so I would like to ask if you have a sample circuit that functions like this.
Thanks!
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dhasmana
Joined: 19 Jan 2005
Posts: 86
Helped: 8
Location: Bangalore , India.
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23 Jan 2008 6:07 Spread Spectrum Clock Generation |
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Have a ramp generator, convert it into pulse , divide this pulse to get the modulation frequency required (divide by 8 or whatever) , use this divided clock to charge discharge a capacitor around a DC value and use this voltage to modulate the current source which is generating the ramp / triangular wave.This will be a loop.This will modulate the ramp @ the freq. of the divided clock.
Regards,
Jitendra.
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23 Jan 2008 6:07 Ads |
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CaPsLoCkE
Joined: 14 Jan 2008
Posts: 6
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25 Jan 2008 16:27 Re: Spread Spectrum Clock Generation |
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| dhasmana wrote: |
Have a ramp generator, convert it into pulse , divide this pulse to get the modulation frequency required (divide by 8 or whatever) , use this divided clock to charge discharge a capacitor around a DC value and use this voltage to modulate the current source which is generating the ramp / triangular wave.This will be a loop.This will modulate the ramp @ the freq. of the divided clock.
Regards,
Jitendra. |
Cool!!! Thanks bro.... Are you pretty sure this will be a stable system? . I tried simulating it at Matlab or Labview based on some of the mathematical facts on your suggestion but couldn't get it running. I need specific data and more info! Would you mind?
Thanks!
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dhasmana
Joined: 19 Jan 2005
Posts: 86
Helped: 8
Location: Bangalore , India.
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25 Jan 2008 16:50 Spread Spectrum Clock Generation |
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| give me ur mail ID.I will write to you... and send a doc.
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CaPsLoCkE
Joined: 14 Jan 2008
Posts: 6
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26 Jan 2008 3:12 Re: Spread Spectrum Clock Generation |
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| dhasmana wrote: |
| give me ur mail ID.I will write to you... and send a doc. |
i sent you an email that contains the my email add. Thanks!
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