Abstract: A reproducing circuit is provided for reproducing digital information recorded in a cassette tape by frequency modulation in which different first and second digital logic levels are respectively represented by first and second repeated signals having respective first and second repeated frequencies, the first repeated frequency being higher than the second. A pulse forming circuit produces first and second pulse signals having the first and second repeated frequencies in response to the signals recorded on the cassette tape. The first or second pulse signals are applied to a one-shot circuit as a trigger signal and to the control input terminal of a flip-flop circuit as a control signal. The output of the one-shot circuit is supplied to the data input terminal of the flip-flop circuit, whereby reproduced digital information corresponding to the digital information recorded on the cassette tape is derived from the output terminal of the flip-flop circuit.

Abstract: A minature computer comprising a main section which includes a central processor, a read only memory storing a monitor program, a random access memory for executing the monitor program and a controlling circuit for peripheral equipments developed which has a hand-held controller electrically connected to the main section through a flat cable, having a keyboard and display device such that the keyboard has keys of a numeral 0 to 9 and the alpha characters A to Z for enabling symbolic languages to be input according to an assembler program. The assembler program is stored in the read only memory and the symbolic languages are converted to corresponding machine languages. The main section has a first jack capable of inputting a program from a audio cassette tape deck and a second jack capable of storing a program in a audio cassette tape deck. The main section also has third and fourth jacks which control the operation of the audio cassette tape decks connected to the first two jacks.