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Wideband Synthesizer + VCO - RF Cafe Forums

Because of the high maintenance needed to monitor and filter spammers from the RF Cafe Forums, I decided that it would be best to just archive the pages to make all the good information posted in the past available for review. It is unfortunate that the scumbags of the world ruin an otherwise useful venue for people wanting to exchanged useful ideas and views. It seems that the more formal social media like Facebook pretty much dominate this kind of venue anymore anyway, so if you would like to post something on RF Cafe's Facebook page, please do.

Below are all of the forum threads, including all the responses to the original posts.


gui076
Post subject: Wideband Synthesizer + VCO Posted: Mon May 05, 2008 10:01 am

Captain

Joined: Mon May 05, 2008 9:56 am
Posts: 15
Location: France
Hello all,

I would like to design a synthesizer which will work from 900 MHz to 2100 MHz. I have seen on the net that VCOs are not very wideband. So my question is how design a synthesizer for a wide frequency purpose ? using several VCOs ? Multipliers ?

Thanks for your help.

Guillaume


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mac
Post subject: Posted: Tue May 06, 2008 6:58 am

Captain


Joined: Fri Nov 02, 2007 3:45 am
Posts: 8
Location: germany
Hi,
look for Synergy VCOs they have some
wideband vcos in stock
DCMO90220-12 might be o.k

or use two overlapping ones - you can
build a synthesizer with the analog devices pll
chips like ADF4107 etc up to 6ghz and that vcos pretty easy-

hope that helps

regards
mac

_________________
regards
mac


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gui076
Post subject: Posted: Tue May 06, 2008 7:55 am

Captain

Joined: Mon May 05, 2008 9:56 am
Posts: 15
Location: France
Hi,

I have the synthesizer from Analog Device but the voltage command Vp will supply only until 5V if i have well understood. The Synergy VCO has to be tune to 24V in order to deliver 2200 MHz.

I'm not an expert in synthesizers

Guillaume


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mac
Post subject: wideband synthesizer, active loop filterPosted: Wed May 07, 2008 7:58 am

Captain


Joined: Fri Nov 02, 2007 3:45 am
Posts: 8
Location: germany
Well,
you can use an active loop filter instead of
a passive one with an opamp boosting your
tuning voltage up to 24Volts - analog devices has got a pll design tool
called adisim you can downlod for free - this will help in
designing the loop filter anyway
and you can choose your
filter topology -
use an op with low noise characteristics

in the end, it depends on your specifications - if phase noise and / or
tuning speed are not your primary goals you can use single chip plls
from other vendors aswell
but remember
synthesizer design is always a compromise between
tuning width/ speed / phase noise etc. the more your specification demands the more complex things will get very soon -

good luck

mac

_________________
regards
mac


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gui076
Post subject: Posted: Mon May 12, 2008 11:09 am

Captain

Joined: Mon May 05, 2008 9:56 am
Posts: 15
Location: France
Hi mac,

Ok for the Op Amp, i have more informations about it and my circuit will be defined for a 12V maximum voltage, so i will try to find some VCOs in this range of voltage.

Regards

Guillaume





Posted  11/12/2012
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