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Erasable magneto-optical recording yields higher storage densities but suffers too from a higher error rate compared to other sequential recording techniques. The principle of magneto-optical recording is explained, the recording medium and the opto-electric pick-up are considered as a transmission channel for digital signals, which is described by its amplitude-frequency characteristics and its noise sources. For a concrete example from the literature in which biphase-coding is used for channel coding an optimum receiving filter is calculated. Compared to receiving filters commonly used with biphase signals the expected error rates will improve by several orders of magnitude.

Because of the very high storage density obtainable, erasable magneto-optical recording is of major interest for use in digital audio. In an experiment with an erasable compact disc (CD) the eight to fourteen modulation code is used for digital recording in order to be compatible with non-erasable CD already available. In this paper the signal, received at the pick-up of a magneto-optical recorder, is considered to be equivalent to an EFM-coded digital signal transmitted by a digital channel. Several receiving filters are compared. With the proposed receiving-filtering an improvement of the signal-to-noise ratio is obtainable.