To shift dc offset sine wave

[vrvrao]

Hello every one,

I have an sine wave of -15v to 15v ( dc-offset is 0 v) and i need to shift it to a sine wave of 0 - 3v with dc offset of 1.5v.

i taught of using diodes but its cutting off the negative half.

as am new in to electonics,So i dont know much about it.

It would be very helpfull for me if u can give some ideas.

thanks

 

[ericgibbs]

hi,
Its possible to do that using a simple operational amplifier circuit.

It would help you could tell us more about the project, whats the source of the +/-15Vsine and whats the +/-1.5Vsine wave going to be used for.??

 

[vrvrao]

hi ,

thanks for reply.

+/-15v supply is from inverter and 0- 3v voltage is to fed controller after converting to pulse.

 

[vrvrao]

hi ,

thanks for reply.


+/-15v supply is from inverter and 0- 3v voltage is to fed controller after converting to pulse.

can you tell me abt the op-amp ckt.

 

[ericgibbs]

can you tell me abt the op-amp ckt.

hi,
This circuit will do what you ask.

E.

EDIT:
What are the details of the pulse you require.?

+/-15v supply is from inverter and 0- 3v voltage is to fed controller after converting to pulse.

 

[vrvrao]

hi,

can we use lt1632 op amp and can we use 28 v supply voltage for the same ckt.

the pulse required is same 0 - 3v with freqency of 2khz.

 

[ericgibbs]

hi,

can we use lt1632 op amp and can we use 28 v supply voltage for the same ckt.

the pulse required is same 0 - 3v with freqency of 2khz.

hi,
The LT1632 looks ok.

You could get a 0/3V square wave directly from a comparator, no need for a level shift stage.

 

[vrvrao]

thanks a lot for your help.

 

[ericgibbs]

thanks a lot for your help.

hi,
This would give a pulse output from a +/-15Vsine input.

 

[vrvrao]

hi,
ya its working. thanks a lot.

 

[vrvrao]

hi,

i have an doubt, can we shift the sine wave without adding an voltage reference like V+ at input.

 

[ericgibbs]

hi,

i have an doubt, can we shift the sine wave without adding an voltage reference like V+ at input.

Thats not easily done.

The voltage reference is only the same +5V as the supply to the OPA.

 

[JimB]

hi,

i have an doubt, can we shift the sine wave without adding an voltage reference like V+ at input.

I am not completely sure what you are asking here, but yes it is possible to raise a sinewave so that it is always above 0v but still a sine shape.

Have a look at my attached sketch.

You could also make the sinewave completely negative by reversing the diode.

There are limits to this technique,
there will be a little bit of offset about one diode drop (0.6v), which may not be a problem depending on what you want to use the signal for.
Also, if you want to use this signal as a clock for something, you will have to use something with a Schmitt circuit or a comparator as Eric has suggested in order to give a fast rise time to the clock. Otherwise you may get some strange effects due to noise and the slow risetime of the sinewave.

JimB