high-speed cassette interface

10-34 — elektor october 1981 high-speed cassette interface J. van Laren Just about as much has been written about data storage as about the entire field of microprocessors, which not only goes to show what a crucial topic it is, but also gives an idea of the problems involved. You rarely hear a computer owner complain that his micropro- cessor is not working; on the other hand, people frequently rant and rage about tapes which their cassette re- corder could not read. Unfortunately, such problems are partly unsolvable, because the recorders used are often just not up to the job. Data is often stored on tape in the form of two frequencies: one representing a logic zero and the other a logic one. This is called Frequency Shift Keying (FSK). found to be rather disappointing, with reliability leaving something to be desired. On paper, the present circuit does not look very reliable either. This is because cassette recorders which are designed for audio purposes are a lot less error-...