Re: [softrock40] Re: 14.100 at 48 kHz rate ...and other frequencies
True, Valpey-Fisher makes good stuff but it's a much more expensive. That's also the clock specification (digital output) which is even better than just a sine wave spec because you
would still have to trigger digital logic VERY repeatably to avoid adding more jitter.
The comparator output (which is a good one) on the AD9851 is spec'd to have a typical output jitter of <80ps. I wonder what the jitter is on a SoftRock at the output of the first FF where you have your first digital signal ? or better yet, at the switches ?
I think you will find that the digital jitter on a SoftRock (at the switches), when using a crystal oscillator or a DDS-60 as the LO, is substantial .......but I don't have any numbers. It may make +/-50ps look pretty good. And, although it matters, it really does not seem to effect SoftRock operation to a great degree.
73 Kees K5BCQ
-- "w5sxd" <rca@...> wrote:
50 ps is terrible phase jitter. The 200 MHz oscillator in the sdr-
1000 is specified at less that one ps. I believe it is a Valpey-
Fisher vf-160 and it's not cheap.
--- In softrock40@yahoogro ups.com, "Kees & Sandy" <windy10605@ ...>
>crystal and one time programmable PLL). They are available for $6.70
> Has anyone tried the little ECS programmable oscillators (uses a
any frequency from 1Mhz to 150Mhz and are programmed for your
specified frequency. Available in 8 pin DIP or SMT.
> Data sheet says +/-50pS jitter if >33.1Mhz.me
> Costs a lot more than a crystal but maybe not a custom crystal.
> 73 Kees K5BCQ
> -- "n2pk2001" <paul@...> wrote:
> Hi Ray,
> > I too would like to order a xtal from ICM. Could you please give
> > the required xtal specifications that I will need to make theorder.
> > I will be ordering for a freq. of 14.100 and 14.220.
> First I went to:
> <http://www.icmfg. com/crystal_ hc49u.html
> and saw that ICM's max Rs was 40 ohms at 3rd overtone for a 56.8 MHz
> crystal. So I just sent them an email with: "I'd like to get a price
> quote and delivery time for ONE 56.8 MHz, 3rd overtone, series
> resonant, HC-49/U crystal. Nothing fancy."
> I'll test the one I got in the next day or two for Rs and Fs.
> Paul, N2PK