[time-nuts] "Vanguard Ultra precision Golden Oscillator"

[Attila Kinali]

On Sun, 23 Aug 2015 19:29:29 -0700
Hal Murray <hmurray at megapathdsl.net> wrote:


> What's magic about a crystal as compared to an osc?  Is it really easier to 
> get an odd-ball frequency in a crystal vs an osc?

As Bob already mentioned, there are more frequencies/types to pick from
when going for single crystals. The reason for this is quite simple: volume.
The volume in this case comes from people who need an oscillator with some
spec. If they build the oscillator themselves, it's just pick a crystal,
some feedback (transistor, logic gate, opamp,..) and measure whether the
specs are met. Repeat until done. The crystal is only one part that helps
meeting the specs, the feedback circuit, power supplies etc are the others.
Because a crystal, in this case, is just a Lego part of a larger device,
they become more versatile and as get a higher volume.

On the other hand, if manufacturer chooses to build a oscillator, the
manufacturer will have to decide on what specs to meet. Of course the
better the specs the more projects it will fit in. But it will also make
the oscillator more expensive and thus a worse fit for cost sensitive
products, that do not need the high specs. I.e. with a pre-build oscillator
the engineer lost one tuning knob with which he can optimize the circuit
for his application.

Things become interesting with "special" devices. E.g. SC Cut crystals
are quite hard to come by. There are few manufacturers who sell them,
while there are many manufacturers that sell oscillators with SC cut crystals.
How market dynamics work in this case, i am not exactly sure.


				Attila Kinali

-- 
I must not become metastable. 
Metastability is the mind-killer.
Metastability is the little-death that brings total obliteration.
I will face my metastability. 
I will permit it to pass over me and through me. 
And when it has gone past I will turn the inner eye to see its path. 
Where the metastability has gone there will be nothing. Only I will remain.