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Generating sine wave and cosine wave

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sp_vibes

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Please can someone tell me how I can generate a sine wave and cosine wave with the option of changing the frequencies of the output waves? I understand it can be done through op amps but I'm struggling to find anything of use through my research?

Thanks
 
You need to search for "Quadrature Oscillator" in Google.

One source is the eBook "Opamps for everyone" by TI.

Op Amps for Everyone Design Guide (Rev. B)

Under the Section of "Quadrature Oscillators" I found the following circuit.
 

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Yeh, I've tried to simulate this but I can't seem to get it working? Is there an input signal to this setup or does it just generate the sine wave and cosine wave when powered up? To change the frequency, I guess I need to change the values of the resistors and capacitors?
 
Hi sp_vibes,

Here's an application from Analog Devices, but they produce
multipliers too so they added a couple to make the oscillator
voltage controlled. If you substitute both multipliers with
a stereo potentiometer and connect each half in series with
R1 and R2 you can vary the frequency and you also could make
C1 and C2 switchable to get different ranges.

**broken link removed**

My simulator says it's ok ! :D

**broken link removed**

on1aag.
 

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Yeh, I've tried to simulate this but I can't seem to get it working?

I tried but it also failed to oscillate in Swcad3. Can someone helps?

Anyone wants to try, here is the circuit file.
 

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I managed to get the circuit oscillating but the distortion is horrible.

I guess it has something to do with saturation of the Opamp output and lack of amplitude stabilization control in the feedback loop.
 

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I managed to get the circuit oscillating but the distortion is horrible.

I guess it has something to do with saturation of the Opamp output and lack of amplitude stabilization control in the feedback loop.

Yes, you need stabilising to give a sinewave - that's probably why it wouldn't oscillate before, and now you've increased the gain until it does, but too much.
 
I managed to get the circuit oscillating but the distortion is horrible.

I guess it has something to do with saturation of the Opamp output and lack of amplitude stabilization control in the feedback loop.

hi,
These two circuits output sin/cos
 

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