Art,

You are assuming a lot about the specs needed. David did not tell us
anything about the specs beside the frequency range, and the approximate
waveform (square). He did not give any clue about the application either.

So far, the SI5351 meet the known specs.

Let David tell us more before entering a contest on Jitter, Phase noise
and agility.

73 de Jean-Paul,
AC9GH


> On Oct 12, 2015, at 5:33 PM, Art <KY1K@myfairpoint.net> wrote:
>=20
> Avoid clock generators if you need low phase noise. They have VERY bad=20
> jitter. They work by running 2 PLL's, each with different divide by N to=
=20
> give the desired output frequency. They operate in the microwave region,=
=20
> then divide down to get the lower desired frequency. The problem is that=
=20
> you are left with very poor phase noise and jitter.
>=20
> If you can tolerate noise on the output and timing that isn't consistent=
=20
> between each successive pulse, then they are viable. When used as a=20
> local oscillator for a software defined radio, they bite bigtime, which=20
> is exactly WHAT I TRIED TO DO:)
>=20
> For frequency agility, the output is disabled for even a small frequency=
=20
> change because both PLL's have to be reprogrammed by your controller and=
=20
> you don't get a usable output until both loops are stable.
>=20
> GL
>=20
> AG
>=20
>=20
>=20
>   On 10/12/2015 04:29 PM, Jean-Paul Louis wrote:
>> Hi David,
>>=20
>> You should look at the Adafruit module below,
>>=20
>> http://www.adafruit.com/product/2045
>>=20
>> Inexpensive clock generator from 8 kHz to 160MHz. Add a divide by 8
>> and you get 1kHz to 20MHz.
>>=20
>> Regards,
>> Jean-Paul
>> AC9GH
>>=20
>>=20
>>=20
>>=20
>>=20
>>> On Oct 11, 2015, at 2:04 PM, David C Brown <dcb.home@gmail.com> wrote:
>>>=20
>>> I am looking for a module to generate logic level square wave up to at
>>> least 20MHz (50 would be better) within a $100 budget.  There are a num=
ber
>>> of items on eBay but none have them seem to have a proper spec.  Any
>>> recommendations from experience?
>>>=20
>>> --=20
>>> __________________________________________
>>> David C Brown
>>> 43 Bings Road
>>> Whaley Bridge
>>> High Peak                           Phone: 01663 733236
>>> Derbyshire                eMail: dcb.home@gmail.com
>>> SK23 7ND          web: www.bings-knowle.co.uk/dcb
>>> <http://www.jb.man.ac.uk/~dcb>
>>> --=20
>>> http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
>>> View/change your membership options at
>>> http://mailman.mit.edu/mailman/listinfo/piclist
>=20
> --=20
> http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
> View/change your membership options at
> http://mailman.mit.edu/mailman/listinfo/piclist


--=20
http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist
.