Kindly explain the signal waveform of the 15Vpp signal.If you want to retain the form, attenuate the signal to 1/3 and you get the swing .Put this in series with a poly cap and clamp the output end with a diode clamp to ground .
The signal will swing -0to -5VDC ...Now you will need to invert this to TTL level
we are doing voltage signal conditioning from (6v to -9v dc) to (0-5v dc).But we cannot get that.Could you please give me a solution with detailed circuit diagram.