| Electronics > Projects, Designs, and Technical Stuff |
| 1.5 to 3 MHz frequency doubler circuit |
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| SiliconWizard:
--- Quote from: Benta on December 27, 2018, 04:15:01 pm ---The comparator is unnecessary and just helps Maxim sell a device. An RC delay into a Schmitt trigger and then into the XOR is enough. You'll need to play around with the RC values. --- End quote --- True. Note that if you use a 74AUP1G86 (single gate XOR), it has schmitt trigger inputs, so no additional component is necessary. Of course an RC delay is not that stable, especially temperature-wise, so you'll inevitably get some drift of the duty cycle, but that should be ok for the op's application. |
| ogden:
--- Quote from: Gandalf_Sr on December 27, 2018, 02:00:04 pm ---I have a design where a Cypress BLE module feeds I2S audio data to a TAS5755M TI Amplifier. The problem is that the Amp needs an extra clock signal called MCLK of 3.072 MHz and it needs to be a doubled, synched multiple the I2S SCLK signal of 1.536 MHz. I built a circuit like this... --- End quote --- You need tuned LC tank multiplier like http://electriciantraining.tpub.com/14181/css/Frequency-Multiplication-95.htm, fast comparator and divide by two flip-flop to generate 1x clock back from multiplied one |
| Gandalf_Sr:
Wow, great responses guys, thanks :D I have played with the R1 C1 values but, as has been predicted, the results can drift or be inconsistent. Now I have several choices to look at: 1. Use a 74AUP1G86 XOR logic IC with Schmitt trigger inputs 1. Use a 74HC4046A PLL IC which will need a divide by 2 circuit for the feedback loop, probably just a JK flip flop 2. Use a tuned LC tank multiplier but won't that produce a sine wave output? I'm discarding the transformer rectifier option as too expensive and large. I will order components for all 3 and test each one. Thanks again. |
| ogden:
--- Quote from: Gandalf_Sr on December 28, 2018, 09:34:29 am ---2. Use a tuned LC tank multiplier but won't that produce a sine wave output? --- End quote --- Yes. That's why comparator was mentioned - to convert sine to square wave. |
| Gandalf_Sr:
--- Quote from: ogden on December 28, 2018, 09:40:59 am --- --- Quote from: Gandalf_Sr on December 28, 2018, 09:34:29 am ---2. Use a tuned LC tank multiplier but won't that produce a sine wave output? --- End quote --- Yes. That's why comparator was mentioned - to convert sine to square wave. --- End quote --- Sorry, not fully awake yet :P |
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