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| Sine to square wave with same frequency |
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| conducteur:
I need to convert a sine wave, from a crystal oscillator (14,31818Mhz) to a square wave, with the same frequency, to drive TTL Logic (74HCT*). Tried to drive a bc547 into saturation, to get a clipped sinewave at the collector, which is connected to +5v with a pull up resistor. Doesn't work, grabbed a second one to get a darlington pair made of 2 bc547. Doesn't work either. I checked the datasheet, and according to me, it should be able to switch 100Mhz? Or am i wrong? BD 679 doesn't work either. The sine wave is between 0 and about +5v (depends on the "load").... |
| grumpydoc:
Just feed it into a 74HCT14 or any other buffer/inverter with a Schmitt trigger input. |
| ocw:
To see a translated version of Samuel Lawrence's sine to square wave converter go to: https://translate.google.com/translate?hl=en&sl=pt&u=http://www.bloguetronica.com/2015/09/modulo-condicionador-de-sinal-sincronos.html&prev=search It uses a TLV3501 as a comparator. He found that his circuit worked up to 80 MHz. I've built something similar which has worked up to 20 MHz. I haven't tested my circuit above that frequency yet. |
| dom0:
(If the 0-5 V signal swing comes directly from the crystal you are probably driving too much power into it.) If you just need a clock signal for something like a microcontroller or sequential logic, just use a 74HC14/HCT. If you don't have 74'14, but 74'04, or want better characteristics use a circuit like this: http://www.taitien.com.tw/db/pictures/modules/CMS/CMS060207001/AP20100105-Utilize%20Clipped%20Sine%20Waveform%20in%20Circuit%20Design.pdf |
| conducteur:
If you search KCO 010T 14,31818 with google, then you'll find the part that generates the sinewave that we got from school for our project. The 74HCT14 is a good idea, so we will give it a try! |
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