| 摘要 |
The apparatus is for scrambling analog audio by quadratic-spectrum inverting and random-carrier-phase drifting without A/D converter and memory to reduce the cost of manufacturing. Its process includes the followings: (A) generating sine wave and cosine wave of random phase of which center frequency is fH by separating horizontal sync. from composite video signal; (B) dividing analog signal into two components, quadrature-amplitude modulating them with the sine and cosine waves respectively to shift its spectrum by fH, and (C) adding them and band-limiting with cutoff frequency of fH to generate scrambled analog signal.
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