Abstract: A plug-in electronic clock being operated either by a commercial power source in a normal state or by a D.C. power source in case of a power failure, said electronic clock having means for generation of a pulse train used for a computation of time information in case of a power failure and means for stopping generation of the said pulse train in a case where the commercial power is active so as to prevent interference noise against radio receivers or television receivers, with a correct time information computation being assured when the commercial power source is recovered.

Abstract: A display in a superheterodyne receiver having a local oscillator, adapted for displaying in a digital manner the frequency of a signal being received by the receiver by counting the local oscillation frequency by means of a preset counter wherein the data for the prescribed intermediate frequency or the complement thereof is preset. A reference voltage is generated by means of a variable resistor for correcting the difference between the preset value for the prescribed intermediate frequency and the actual intermediate frequency of the intermediate frequency stage of a receiver as actually manufactured, and a comparison voltage is obtained by digital/analog converting the output of a multiple-bit counter which is stepped responsive to clock pulses.

Abstract: A keyboard type electronic musical instrument wherein tone assignment signals (key depression signals) designated by depressing desired keys of keyboards are transmitted to an electronic circuit block through only one signal line per sort of keyboard as time-divided serial timing signals. The electronic circuit block includes therein a circuit which generates parallel output signals having respectively different timings in correspondence with notes of the keyboards. The parallel timing signals are respectively sent to the corresponding key switches of the keyboards, they are selected by turning "on" the switches, and they are converted by OR circuits into serial timing signals representative of the selected notes. The serial timing signals are sent to a device for detecting and storing notes or chords, whereupon as in prior arts, a tone signal is generated from the obtained signal indicative of a note or chord by tone signal producing device and it is amplified and provided as an output by a loudspeaker.

Abstract: A keyboard type automatic accompanying system wherein information representative of the root note of a chord and the type thereof are detected from key depression signals assigned by depressing a plurality of desired keys of an accompanying keyboard, the detected information are stored, and an automatic chord complying with the particular chord are accompanied. A chord detector comprises in combination a shift register which stores the accompanying key assignment signals therein and which shifts the stored contents cyclically, and a ROM device in which binary information indicative of the basic forms of chord names and the types of chords are stored. Outputs of the shift register are applied to the ROM device, and the type and the root note of the chord are detected in one shift cycle of the shift register, so that the circuit arrangement is simplified, that the detecting time is shortened and that the key response rate is enhanced.