sine wave generator (without oscilator)

[aliraza786]

hello everyone...
i have a problem please see the attached pics of the circuit.
i wana combine two wave form one is psituve and the 2nd one is negative going. i take positive half cycle form +ve wave and -ve half cycle form -ve wave and combien them to form a complete wave consist of +ve and -ve cycles . my circut and output in osciloscope i showed in pics kindly check this out becuse the output is not like as i required

 

[capcas]

There is a timing difference in the channel selection signals(which are applied to mux 4051). I think they are not selecting the channel at appropriate time. You are getting the combine effect but not exactly from 180 deg.

 

[aliraza786]

thnku so much for your reply kindly tell me how can in remove this anyother mehtod for switching.? or any improvment in the current design.?

 

[capcas]

you have to design a phase compensation circuit at the output of both analog circuit. You can adjust the phase of the analog circuit to get the sine wave. Phase compensation are easily built by using op-amp.

 

[aliraza786]

ok can you give me some link to such circuit where i can study and then implement it.... thnks again..............................

 

[capcas]

I cant post any ebook but you can get a complete design in "Operational Amplifiers and Linear ICs" by David A. Bell. it is a very *** book for op amp circuit.