US 4204453

US4204453A — Patent Overview

Title: Device for automatic tonal accompaniment in electronic musical instruments

Patent number: US4204453A
Application number: US05/862,006
Inventor: Ulrich Gross
Original/current assignee: US Philips Corp
Priority date: 1976-12-29
Filing date: 1977-12-19
Publication (grant) date: 1980-05-27
Legal status as listed: Expired – Lifetime; anticipated expiration 1997-12-19
Source: https://patents.google.com/patent/[US4204453](/patent/US4204453)/en

Purpose

The invention relates to a device for automatic tonal accompaniment in electronic musical instruments equipped with a rhythm unit, wherein "the fundamental, the quint or another tone related to specific chords [is] held and/or the chord itself becoming available in a predetermined sequence in the selected rhythm." The text identifies German Patent Application No. 2,056,509 (laid open for public inspection) as a known device that selects the highest and lowest tones from held chords and reproduces these alternately with the chords.

Plain-language scope

For at least one tonal key, a chord sensor identifies the character of a held chord (e.g., major, minor, seventh) and outputs a signal when a chord is present. A switching device added to the chord sensor switches it to identification of individual tones in the absence of a chord. In the described arrangement, each chord sensor's output goes both to a first input of one of twelve switches (together forming the switching device) and to an OR-circuit input; the switches' second inputs receive a key signal of a preselected tone (e.g., the fundamental). The OR-circuit output drives all switch control inputs; switch outputs feed a priority circuit, whose outputs control further switches gating tone signals and rhythm-unit control pulses, combined via an OR-circuit (resistors R1–R12). The excerpt also describes 12-bit cyclic shift registers, HF clock generator pulses, counters/decoders, a comparator, and chord memory for detecting tones and identifying chords.

What the excerpt does not establish

The excerpt is partial and omits claim language, the full description, drawing contents, and most reference citations. It does not establish claim scope, validity, litigation, ownership transfers, or prior-art effect; no such analysis is provided here. Classifications listed (e.g., G10H1/383, Y10S84/22) are as reported by the source.