[time-nuts] "Vanguard Ultra precision Golden Oscillator"
kb8tq at n1k.org
Sun Aug 23 17:02:22 EDT 2015
If all the spec’s on it are lies, then of course they don’t help much at all. I have
not contacted the seller with any questions. I have no idea if there is more data
on the parts or not. Some parts from other sellers with very similar markings have
quite good paper specs associated with them.
There are technologies that have been used on similar products over the years that result
in parts that do not meet that phase noise spec at any point in the frequency range from
6 to 100 MHz. Those are the parts that you probably don’t want to use on
your DDS clock.
The spec he states is quite do-able over that range without a lot of effort on an XO.
Who knows if he meets it or not. I certainly know of no reason why he could not do so.
He might exceed the spec by quite a bit at one end …
The header production process is a fraction of a cent cheaper if you use all glass seals
than if you weld one of the leads. In that case, you simply hand weld a ground onto the
base. A bit ugly, but they save money. Inductance wise, not much difference. It’s miles ahead
of any of the modern ceramic packages in terms of shielding either way.
> On Aug 23, 2015, at 2:55 PM, David <t_list_1_only at braw.co.uk> wrote:
> > The most encouraging thing is that there *is* a phase noise spec on it.
> BUT its seems to be the same spec on all irrespective of carrier frequency which goes from to 6MHz to 100MHz, with similar design the time jitter may be somewhat similar but I'd be astonished if the phase noise was common to all (implying grossly different time jitter). In addition, the package would worry me, 4 pins all with a glass seal, I want the ground pin to be directly connected to the case to minimise ground inductance leading to issues like injection locking. I'd assume these are cheap and cheerful clock oscillators, similar can be bought with a known brand label and spec from Digikey etc for less $.
> Message: 14
> Date: Sun, 23 Aug 2015 08:33:59 -0400
> From: Bob Camp <kb8tq at n1k.org>
> To: GandalfG8 at aol.com, Discussion of precise time and frequency
> measurement <time-nuts at febo.com>
> Subject: Re: [time-nuts] "Vanguard Ultra precision Golden Oscillator"
> Message-ID: <86ABCF10-FC65-4713-B286-BDC3E33FEB8E at n1k.org>
> Content-Type: text/plain; charset=utf-8
> A few things I would wonder about:
> 1) Is it 0.1 ppm over 0 to 50C (or some other range)? If not, what is the temperature stability?
> 2) Does it run at 3.3V -or- at 5V (pick one) or do they run equally well at either voltage?
> 3) Since there is no EFC, is 0.1 ppm the set tolerance? If it’s not, what is the initial accuracy?
> Lots of questions, there’s not much information there. That may be due to the seller not
> having the information. It also may just be because nobody ever asked. The term TCXO can
> mean a variety of things to a different people ….
> The most encouraging thing is that there *is* a phase noise spec on it.
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