To get a "Dalek" voice effect, you're supposed to modulate with a 30 Hz sine wave (although sometimes BBC ran the sine wave tape at the wrong speed and so modulated with the wrong frequency.) And part of the effect is just to speak with a harsh voice with rising inflections.
Would it make much difference if you used a 30 Hz square wave instead of a sine wave? (sine wave generators are much more complicated than sq wave)
(I've been watching Doctor Who episodes on DVD)
