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symsnowfairy
Joined: 07 May 2008
Posts: 112
Helped: 27
Location: Germany
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 11 Jul 2008 11:39 Why use VCO? |
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| Excuse me, the oscillators with fixed oscillation frequency usually have relatively higher Q factor, so why do we use VCO?
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Old Nick
Joined: 14 Sep 2007
Posts: 387
Helped: 48
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| 11 Jul 2008 11:54 Re: Why use VCO? |
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The answer is in your question.
One is controlled and one is fixed.
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alexandr22061986
Joined: 16 May 2007
Posts: 165
Helped: 7
Location: Ukraine
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| 12 Jul 2008 12:28 Why use VCO? |
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| VCO used as a part of many circuits, for example PLL
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symsnowfairy
Joined: 07 May 2008
Posts: 112
Helped: 27
Location: Germany
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| 13 Jul 2008 11:33 Re: Why use VCO? |
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I think my question is not clear enough.
I guess it is because tunable filter is not easily realized, we use VCO to get a fixed output frequency although the input signal is of different frequencies.
Last edited by symsnowfairy on 13 Jul 2008 22:36; edited 1 time in total |
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ND
Joined: 25 Sep 2007
Posts: 54
Helped: 12
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| 13 Jul 2008 21:09 Re: Why use VCO? |
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I don't understand you, know.
But i think Old Nick's answer is Ok.
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dinesh agarwal
Joined: 20 Oct 2007
Posts: 139
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| 25 Jul 2008 12:42 Why use VCO? |
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| totally application specific
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rudane
Joined: 26 Mar 2004
Posts: 32
Helped: 5
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| 25 Jul 2008 15:28 Re: Why use VCO? |
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Well I can give one example for you ... you have to understand mixing and intermediate frequencies to get it:
I've just worked on a project where we used a magnetron as a source. The frequency drifts with temperature changes. The source is mixed a few times and filtered (A SAW filter, very high Q). If the source drifts too much then when we mix, the resulting signal does not make it through the passband. The only thing we could do was design a PLL with a VCO so we could change intermediate frequencies, which would bring the resultant back into the passband.
Hope this isn't too complicated.
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