[time-nuts] WWVB d-psk-r down conversion method
kb8tq at n1k.org
Tue Sep 23 07:37:59 EDT 2014
Actually stability isn’t the main problem with the progamables. The issue is usually phase noise ad spurs. Often they use odd multi modulo divides rather than a PLL. That gives them a low cost chip, but the output spectrum is pretty poor. Figuring out if you have a “bad one” or not is tough from many data sheets. It’s rare that cheap XO’s come with phase noise and spur plots.
On Sep 23, 2014, at 12:04 AM, Hal Murray <hmurray at megapathdsl.net> wrote:
> paulswedb at gmail.com said:
>> Did try lots of frequencies and divider math to come up with a simple LO
>> scheme for 61 or 59 KHz. Messy.
> There are companies that will make a crystal or oscillator at any frequency
> you want at a not silly price. Delivery is not overnight.
> Beware: There are several companies selling instant delivery of oscillators
> running at any frequency you want. They are using a programmable PLL so you
> won't get the stability you expect from a crystal.
> These are my opinions. I hate spam.
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