Need help with Crystal Oscillator circuit...

ci139

Joined Jul 11, 2016
1,696
Dear Sir , you must realize that the X-tals would be interrelated if you attempt to route an energizing pulse to each one of them from the single source
. . . yes, they all will show fading oscillation pattern of few nA and perhaps couple of mV . . . it does not much make any sense to do so -- however it would be possible to advise you how to set up an experiment if you'd give any hint what you want to achieve as an output of such
 

ci139

Joined Jul 11, 2016
1,696
(not booting yet) if you just need a pulse of certain power use a comparator or the mosfet gate driver ???
(( it would be a tough nut to bite through . . . if it is possible as the TS thought it could . . . the problem -- is the problem is not yet specified ))
EDIT :: a random simulation of 2 slightly "offset" crystals
RND X-Tal - TEST.png
 
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Ian0

Joined Aug 7, 2020
4,122
It is tricky to do. The drive circuit has to go high-impedance after the end of the pulse, so that the ringing waveform can be observed.
So - perhaps a PNP transistor connected to each crystal through a diode. (Preferring a bipolar transitor over a MOSFET due to its lower output capacitance, despite its slower switch-off)
Only problem is that the crystal capacitance is very small, so that all the crystals would effectively all be coupled together by the diode reverse capacitance which would be significant.
 

MrChips

Joined Oct 2, 2009
25,037
How about an optical switch to trigger each oscillator?

I still speculate that coupling through the power supply will put them all in sync.
 

Ian0

Joined Aug 7, 2020
4,122
It's worth a go.
Agree about the power supply coupling. Once had a colleague who tried to make a 3-channel random light flasher. Three 555s each drove a triac. The triac gate current dipped the DC supply. Started off random, but all channels were in sync in under a minute!
 

MisterBill2

Joined Jan 23, 2018
10,545
32,000 Hertz versus 1 Hertz. Anyone see a problem with the notion of using 32Khz crystals for a 1 second click? There's going to be a need for some circuitry to divide these 32,000 pulses down to a single pulse per second.

And so do I. Why? What are you hoping to (dis)prove?
I can see that the one hertz pulsing will get the crystals to ring for a bit, And if a single counter is used to read frequency it will take about 250 seconds, not bad at all. But I do not know how long those crystals will ring for, and that matters quite a lot. And still I can't even guess what the purpose is.
 

atferrari

Joined Jan 6, 2004
4,511
How about an optical switch to trigger each oscillator?

I still speculate that coupling through the power supply will put them all in sync.
In spite of the pulse reaching each oscillator in exactly the same instant, would they start to oscillate in sync? I doubt so.

I built a dual NCO with two 16F84A driven with the same xtal oscillator via 2 buffers providing the clock signal. The distribution in the PCB was pretty much symmetric (if that matters, for this case).

Dare to say that one of them, 80% of the time started at a more or less fixed amount behind the other but never in sync.
 

Ian0

Joined Aug 7, 2020
4,122
If they were started by putting a DC voltage across the crystals then releasing it, then I think that they'd start in sync.
Differences in turn-off time of the optocouplers might be a problem.
. . .beginning to think that the purpose of this post was to get a bunch of engineers to discuss something completely pointless.
 

Tonyr1084

Joined Sep 24, 2015
6,612
Those pendulums had quite an effect on the rocking table. How much effect are those tiny crystals going to have on each other? And given that they vibrate so fast - I don't think you're going to find any substrate you can place them on that will allow for motion from one xtal to another. Let alone 250 of them.

How'd you come across 250 of them? Watchmaker maybe?
 

ci139

Joined Jul 11, 2016
1,696
something completely pointless.
if one can wick some stats. out of the X-tal mesh . . . the results might be . . . interesting . . . no matter the fact whether the X-tals be inter-coupled (? energy walk in between X-tals before the entropy settles the thingy) or isolated (quite good stats about the precision inside the 32k "the voluntary system of . . . multiple clock sources")
 
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