SndScopePro 1.5 Dual Trace Sound Card Scope Professional Dual Trace Oscilloscope AC DC Triggered Input Single / Dual channel Volts / DB Digital Readout Time / Frequency Digital Readout Auto Gain Function Plus Much More By using the sound card line inputs (left/right channels) a low cost Dual Trace Scope is possible, scope has many adjustments and can be used as is without additional hardware, with a small box with Calibrated 10 turn pots and freq dividers, you can use the scope for any amptitude or frequency.
formatting link