There is no sine wave option in the oscillator section, but you can produce a sine wave with the help of the self-oscillating filter. Just turn on the 4 pole setting, turn the resonance knob fully clockwise, and set the key amount to a value of 64, which will cause the filter to be tracked in half-step increments from the keyboard. You will have to tune the actual pitch with the cutoff knob. To make sure the self-oscillating filter is tuned to the standard setting of one of the oscillators, you can fade in and out the resonance until you achieved the same pitch. The latter is necessary, as the self-oscillating filter will drown out the pure oscillator sound. Another option for tuning would be to simply switch between layers A and B in order to compare pitches.