The sound card cannot output or record dc voltages. Since we are using it as a data acquisition card, this may be necessary in some applications. It is required to design and build electronic circuits that extend the sound card’s capability to dc. On the input, you are to enable the sound card to handle inputs and outputs between −V and V dc. The output must be able to drive a load of 10ohm. Issues to consider are the simplicity of the solution, the accuracy of the system. Additionally, for the output you should pay attention to the power efficiency, and for the input to the purity of the signal (that is the level of distortion).
Basic idea: use 555 timer, amplitude modulator and amplifier. Output of amplifier will be input of sound card. Take output of the soundcard (AC) to Peak Detector, amplifier/scaler, adder, power amplifier and then to load.