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PLL HMC783 Hittite

Question asked by sdruart on May 29, 2015
Latest reply on Jun 4, 2015 by MRichardson

Hi all,

 

I'm new in the design of rf tranceivers. I purchased the evaluation board of the HMC783 PLL part.

I have a question about the FSK modulation possibility of this MMIC.

Is it a coherent FSK modulation ? I mean, is the phase continuous when jumping from f0 to f1 and vice versa? I suppose this is the case since this is a PLL circuit . I just want to have confirmation about that before going further in my work. Perhaps I misread it in the datasheet and I'm sorry for this. Also, does somebody have an idea of the maximum frequency modulation rate ? ('fm' has written page A-11 in the operation manual of the PLL). I don't really understand the following sentence on the bottom of this page:

"For practical FSK transmissions the fm rate is limited by the radio link budget, channel spectral emission restrictions and practical closed loop bandwidths of the fractional PLL with Integrated VCO"

 

Many thanks,

Sylvain

 

PS:

Operation manual link:

https://www.hittite.com/content/documents/operating_guide/pll_operating_guide_mwave_vcos.pdf

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