square to sine wave help

[TONIGALEA]

Hi Everyone
Please do anyone have a simple circuit that would take
an input square wave 50/50 and output a sine wave.
the range would be between 1 to 2 khz
Any pointers would be very much appreciated


Toni

[bot402]

First convert the square wave into a triangle wave, then round the edges of the triangle wave.

A search on Google should give you plenty of circuits for square to sine, square to triangle, and triangle to sine.

[mister_e]

That's what we call an integrator. Integrate 2 time should works good. more than 2 time work better. It depend of the distortion % you want live with.

at the end you'll probably need to amplify the gain du to the loss in the filtering/integration process.

a Quad Op-Amp TL074,TL084 or a dusty LM324 should works great for that frequency range.

[isaac]

Thanks for all your replies but i still find it difficult to find a circuit that
would do the conversion from square to sine wave so i am going to use
two wien bridge oscillators to generate the 2 different audio sine waves
that i need and use an analogue switch to select the the individual oscillator
if anyone has done square wave to sine using op amps i would be glad to
to hear from you

Best Regards
Isaac

[mister_e]

look at
http://www.chem.uoa.gr/applets/AppletOpAmps/Text_OpAmps2.htm
http://www.allaboutcircuits.com/vol_6/chpt_6/6.html
http://webpages.ursinus.edu/lriley/ref/circuits/node5.html#fig:opint


and ... LMAO!!! a really quik one :)
http://lhcb-elec.web.cern.ch/lhcb-elec/_electronics/00000031.htm

[psdayama]

look at
http://www.chem.uoa.gr/applets/AppletOpAmps/Text_OpAmps2.htm
http://www.allaboutcircuits.com/vol_6/chpt_6/6.html
http://webpages.ursinus.edu/lriley/ref/circuits/node5.html#fig:opint


and ... LMAO!!! a really quik one :)
http://lhcb-elec.web.cern.ch/lhcb-elec/_electronics/00000031.htm
I checked these links and found to be very preliminary.
U should check the National Semiconductor's Opamp Circuits Application
note. If Ur input frequency is fixed then use Bandpass filter -Besel or Chebishev type tuned to that frequncy as centre of bandpass.With LM324
U can do upto 2-300Hz but with TLO64 or better U can go to 10Khz. With
the quad opamp U can make 2stage filter with very low distortion.U may
need additional gain stage for final output.

[Acetronics2]

Hi,All

May be a look ( or search ) with the keyword DDS could lead s/o to fair solutions : simple ones with a piece of "old S Logic" and more sophisticated one with programmable specialised chips.

see also AD 9835 and its little brothers ...

Alain