[hpsdr] Horton LO

[John B. Stephensen]

The disadvantage of dividing down a 1-2 GHz VCO is that the ECL dividers
have a -145 to -155 dBc/Hz broadband noise floor, depending on which
dividers are used. 100-200 MHz will work with CMOS CPLDs, which should have
a lower noise floor. Some CPLDs will work to 300-400 MHz.

73,

John
KD6OZH

----- Original Message ----- 
From: "Philip Covington" <p.covington at gmail.com>
To: "Phil Harman" <pvharman at arach.net.au>
Cc: "High Performance Software Defined Radio Discussion List"
<hpsdr at hpsdr.org>
Sent: Saturday, June 17, 2006 03:28 UTC
Subject: Re: [hpsdr] Horton LO


> ***** High Performance Software Defined Radio Discussion List *****
>
> On 6/16/06, Philip Covington <p.covington at gmail.com> wrote:
> > On 6/16/06, Phil Harman <pvharman at arach.net.au> wrote:
> > > ***** High Performance Software Defined Radio Discussion List *****
> > >
> > > Ok - I worked through Phil C's math last night and it looks fine to
me. I
> > > will draw up a block diagram and the divider list today and post to
the
> > > forum.
> > >
> > > Phil...VK6APH
> >
> > Hi Phil,
> >
> > Take a look at the Minicircuits ROS-2150VW.  Its tuning range is
> > 970-2150 and the phase noise isn't too horrible.  This with a National
> > PLL tuning in coarse steps might do it.  We'd have to divide down into
> > a range where the CPLD or FPGA would handle the final divider chain.
> >
> > 73 de Phil N8VB
> >
>
> Basically what I was thinking about back then is a modern day version
> of the HP 8640B.  HP takes a cavity oscillator and divides it down to
> give you the ranges from 512 down to 0.5 MHz with good phase noise.
> With a PLL and VCO running in the 1000-2000 MHz range (like the
> ROS-2150VW or a home made VCO) we would program the PLL and divider
> chain to give us ham band coverage with 10kHz steps or less.  The
> steps get smaller as we divide more, but since we know exactly what
> the step size is for a given divide ratio we can take care of the
> steps in software.  Initially I was going to use 100-200 MHz, but
> higher ranges will work better (like Phil H's microwave VCO
> suggestion).
>
> 73 de Phil N8VB
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