Well Mahesh,

If you want to generate a square wave, you can use any microcontroller like the MCS51 family or derivatives, ATmega, PIC etc. The output level will be the logic voltages between 0 to 5V. You can use a resistor divider to scale this output to 0-1V level and then using an op-amp adder/subtractor, to inject -0.2V into it so that your output swing will now span from -0.2V to +0.8V. Hope this idea meets your exact requirement!

Best Luck!

Well said by Prasanna

Logic level ( high) is decided by the Vcc/Vdd supplied. So design pottential divider and op-amps based on your logic level

@ Vasile,

What you have stated is 100% correct so we have a simple chip like op-amp 741 or the popular timer IC555 to a much sophisticated quad-core GHz processor. What matters most is the timing accuracy, ease of tuning and last but the most important is the COST EFFECTIVE SOLUTION to meet the desired requirement. When a particular hardware is decided, say as with Mahesh, the requirement is to generate a sq. wave from X51 family (or any other controller) device and to produce the specified output in the range of -0.2V to +0.8V. I do not think it will be "A HAPPY MARRIAGE" of an op-amp with a quad-core processor! Will that be?

Dear Friend Vasile,

Yes, I do agree with you regarding accurate timing generation - always advisable to use timers and interrupts and not the C versions.

I appreciate your society called "Mixed Design" where Happy marriages exits between RF and Opamp! Hopefully the RAMBO quad-core will not directly marry an op-amp - otherwise NGOs will run after claiming a child marriage!!!

Dear sir  

Thanks for answering my Q.

If you need simple and microcontroller free implementation you can use the 555 in astable operation to generate digital signal with frequency of 40 Hz. The scalling to 0.2V-0.8V can be simply performed with three resistors and some math.

All resistor values, calculation and schematics are attached in this message. Simulation of the output levels is also performed.

Hope it helps,

Regards,

Zivko

thank  you sir for valuable reply.... it really helped me  

you can also use DAC with mc

Hello Pushkar,

In that case Mahesh will have to spare many port-lines of his micro at least 3-lines for SPI DAC and then 8-bits when using a parallel DAC and so on. Then again the output op-amp circuit is needed for the DAC. That adds the cost and the chip count. When only a square-wave is needed as I have stated we can use only 1 bit ( or single port line) with a voltage divider and the op-amp buffer to get the desired output.

Thanks,