Generate a square wave using crystal

Thread Starter

dumindu89

Joined Oct 28, 2010
113
I need to get a square wave and voltage levels are similar LVTTL input levels using a crystal.

How can I do this? what is the easiest way?
 

panic mode

Joined Oct 10, 2011
1,865
use crystal oscillator then run the signal through gate with Schmidt trigger. it will square it even if input was sine wave. if you want 50% duty cycle, add flipflop. there is tons of circuits that produce signal you require. if the frequency need some adjustment, use PLL chip.
 

Thread Starter

dumindu89

Joined Oct 28, 2010
113
use crystal oscillator then run the signal through gate with Schmidt trigger. it will square it even if input was sine wave. if you want 50% duty cycle, add flipflop. there is tons of circuits that produce signal you require. if the frequency need some adjustment, use PLL chip.
Can you explain bit more?
Yeah. I need a square wave with 50% duty cycle.


I implemented the circuit shown in the following figure which is designed for TTL. It worked fine with TTL 7404 IC.



Link to the web page: http://www.eleccircuit.com/crystal-oscillator-using-ttl/

But it didn't work with the NOT gates implemented using the Altera MAX ii CPLD (LVTTL). :(
Any suggestion to make it work with LVTTL? Is it possible to make it work with LVTTL by changing the R1 and R4 values?
 

Dodgydave

Joined Jun 22, 2012
9,685
All the circuits are designed for TTL devices instead of LVTTL. The previous one which is designed for TTL is didn't work with LVTTL. (refer the previous post). Will these circuits work with LVTTL?


Guys!! Any Idea please?
Use a CD4069 chip it will work on 3 v, or use a a LVTTL
 
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