Abstract: A key signal input circuit for a microcomputer including a microprocessor and a single input port. The microcomputer outputs, in sequence at a constant interval, a plurality of grid signals, receives different key signal inputs successively through the single input port synchronously with the grid signals, and discriminates the inputted key signals to recognize which keys have been selected. The key signal input circuit includes a power supply circuit, responsive to the grid signals from the microcomputer, having a plurality of power supply lines for supplying, in sequence at a constant interval, a desired power through the power supply lines. A key matrix circuit having a plurality of sets of keys, responsive to the desired power through the power supply lines from the power supply circuit and to on/off states of the keys, coupled, by sets, respectively to the power supply lines. The key matrix circuit applies the key signals successively to the microcomputer.

Abstract: An automatic clock-setting apparatus and method, which can recognize clock-displaying characters as numerals included in a television broadcasting signal when the clock-displaying characters are displayed on a screen, and which can automatically set a current time of a built-in timer of a television or a video cassette recorder by the recognized numerals. According to the invention, it is possible to set a clock exactly and to make the clock-setting operation by the user convenient.

Abstract: An apparatus and a method for automatically controlling pulse generation. The apparatus comprises a drum having video heads, a pulse generating head and a frequency generation head, first and second wave-shapers for wave-shaping a pulse generation signal from the pulse generating head and a frequency generation signal from the frequency generating head, respectively. There is also provided a mono-multi signal generator outputting a mono-multi signal having a rising curve time, a servo device for outputting a head switching signal in response to the mono-multi signal and outputting a drum control signal in response to the pulse and frequency generation signals and the head switching signal to control the speed and phase of the drum.