Sinusoidal Pulse Width Modulation using IC555 and OP-AMP

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07:29:16

Sinusoidal Pulse width modulation using IC555. IC555 is generating the high frequency carrier wave which is compared against a Sine wave of lower frequency using a comparator. The output is thus the sine PWM. The LED indicators and the 7 segment display are showing the HIGH/LOW of the output waveform.

*Note: You can change the carrier wave frequency by tuning the potentiometer connected to the IC555.

published 6 years ago

hurz

6 years ago

I changed nothing, just the frrquency of your sine wave from 2kHz down to 200Hz and it does not look like a PWM signal. I can not imagin to reconsruct a sinewave from this signal. http://everycircuit.com/circuit/5149015600267264

VivekChoubey

6 years ago

@hurz you also need to change the frequency of the carrier wave as well otherwise you will not get desired result. Carrier wave should also be around 500-1kHz i.e, proportionally greater.

VivekChoubey

6 years ago

Also this simulator doesn't give the desired results for a number of circuits and shows incorrect results. I don't see any reason for the circuit not to work.

hurz

6 years ago

an audio signal is from 20Hz upto 20kHz so if i want to use your modulator what carrier frequency do you recommend. Something close to 20Hz??? No it must be something much higher then 20kHz and probably starts at >200kHz. So what is yout recommendation, i still think your modulator does not work. Its not the simulator.

VivekChoubey

6 years ago

@hurz yeah maybe the problem is with the design. Can you suggest something because I am just using the simple blocks that I have learned so far by making a Voltage Source Inverter.

VivekChoubey

6 years ago

@hurz I did some modifications in the circuit. Actually the carrier wave should be triangular and not square. Here's a corrected model please check this out http://everycircuit.com/circuit/6679585077592064

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