hi friends,
these days i am tring to make ultrasonic range meter,and almost it is completed and tested sucessfully,but there is problem with it it runs well from 12v battery,12v supply made from main,but it fails when i give main suppy fron ups and ups is on means invertor mode of ups is on,when i checked signals on cro on ic4 ,pin number 7 gives clear signal while there is distortion on pin 2 of ic4 what is the possible cause why it happen on ups.
http://www.8052.com/users/kuldeep/cir.pdf
please help

kuldeep singh