square to sine

Status
Not open for further replies.
T

trexter711

New Member
It was a long time ago when I got the theories.
I need someone to remember me how to change a square to a sine wave using an op-amp.

Thanks
 
You don't, at least not very easily, and not without limitations - the other way round is easy though!.
 
What about a basic inductor/capacitor tank circuit?
Opamps can be made to simulate inductors at least for wave shapeing. A dual opamp set should be able to convert a square to a sine within the acuracy of the capacitors used.
 
Sceadwian said:
What about a basic inductor/capacitor tank circuit?
Opamps can be made to simulate inductors at least for wave shapeing. A dual opamp set should be able to convert a square to a sine within the acuracy of the capacitors used.
Click to expand...

At a specific frequency though!.
 
trexter711 said:
It was a long time ago when I got the theories.
I need someone to remember me how to change a square to a sine wave using an op-amp.

Thanks
Click to expand...

Use the breakpoint method: diodes are used to implement a non-linear transfer function, switching resistors into the feed-back loop. Fisrt, you should convert the square wave into a triangular wave.
 
The original poster asked how to convert a square wave into a sine, there was no mention about multiple frequencies or bandwidths or modulation methods or anything of that nature, why would I even bother contimplating it if the poster didn't make it a requirement?
 
eng1 said:
Fisrt, you should convert the square wave into a triangular wave.
Click to expand...
But that's frequency dependent and you need a constant amplitude triangle wave for a sine or cosine converter to work.

You could use a microcontroller but it will be limited to low frequencies, it depends on how high you want to go.
 
Hero999 said:
But that's frequency dependent and you need a constant amplitude triangle wave for a sine or cosine converter to work.

You could use a microcontroller but it will be limited to low frequencies, it depends on how high you want to go.
Click to expand...

The square->triangle is just an integrator and is frequency independent. Keeping it centered and scaled correctly is the fun part though.
 
My very low distortion sine-wave generator has a variable square-wave frequency, a phase-locked-loop and counter to boost the frequency, a 10-steps sine-rough-shaper then an 8th-order switched capacitor Butterworth lowpass filter. Even without the sine-rough-shaper (it oversamples 10 times) the sine-wave is pretty good.

You could hack into an ICL8038 waveform generator and use its sine-shaper circuit. Its distortion is about 1%. The distortion is audible and can be seen on a 'scope.
 
trexter711 said:
It was a long time ago when I got the theories.
I need someone to remember me how to change a square to a sine wave using an op-amp.

Thanks
Click to expand...
a high Q ckt , tuned to fundamental freq of square wave.
 
Status
Not open for further replies.

Similar threads

K
  • Question
Want to convert from 9v alkaline to solar rechargeable
2
Replies
20
Views
2K
ZipZapOuch
A
  • Solved
Buck/Boost Converter
Replies
7
Views
1K
Tony Stewart
C
  • Question
Is there a way to convert SGL8022W touch switch to momentary switch?
Replies
4
Views
752
call_sign_diesel
C
A
  • Question
Using latches to capture 8086 bus
Replies
3
Views
831
rjenkinsgb
L
spot weld wire to wire?
Replies
15
Views
2K
ChrisP58
Menu
Log in
Register
Cookies are required to use this site. You must accept them to continue using the site. Learn more…