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Need help in understanding VCO Specifications

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eee100

eee100

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VCO Specifications

Hello all,

I am planning to use a VCO from Crystek. In the component's datasheet there are two specifications that I couldn't understand.

Pushing: 5.0 MHz/V
Pulling,all phases: 3.0 MHz pk-pk

What do they mean? I couldn't find any info explaining those. Thanks.
 

VCO Specifications

Pushing is a figure of merit of a VCO against supply voltage variations.In your case, if the supply voltage is changed 1V, the VCO frequency will shift 5MHz ( ascending or descending )
Pulling is is the sensitivity of the VCO frequency against load variations.In this case your VCO frequency will drift 3MHzpk with certain load mismatch compare to nominal impedance.
 

VCO Specifications

Thank you for your reply BigBoss.
I still couln't get the pushing part. You said that if the supply voltage is changed 1V, the VCO frequency will shift 5MHz but the tuning is also made with supply voltage. In the datasheet it says that the tuning sensitivity is 47 MHz/V. So this means that 1V supply voltage change will shift the freq. by 47 MHz. Now my question is what is the difference between pushing and tuning? Thanks
 

Re: VCO Specifications

FREQUENCY PUSHING:
The changing of output frequency corresponding to a given
change in the supply voltage at a fixed tuning voltage
(expressed in MHz per volt).


In your case, they probably fix the tuning voltage half way between 0 and the supply rail during the test. It is important, since switching voltage reulators put out a lot of voltage ripple, that can get into the VCO output frequency causing spurious tones.

https://www.minicircuits.com/pages/pdfs/AN95003.pdf
 

VCO Specifications

Thank you biff44. The link is very helpful for me :)
 

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