| 摘要 |
An apparatus and method for demodulating a synchronous signal utilising a pulse width-modulated equivalent of a modified square wave function to eliminate lower order harmonic distortion. The apparatus includes a switching demodulator 12 which is controlled by a function generator 16 which is synchronised to the input signal. The function generator produces a controlling function which is a square wave function having a fundamental component and an infinite series of odd harmonics of said fundamental component, less at least one of said odd harmonics. The function generator comprises an addressable memory 14 in which the controlling function is stored. The first one of the infinite series of odd harmonics is deleted from the square wave function. In a further example the third, fifth, seventh and ninth harmonics are deleted from the square wave function. <IMAGE> |
