Processor controlled sound synthesizer

• US 4,272,649 A
• Filed: 04/09/1979
• Issued: 06/09/1981
• Est. Priority Date: 04/09/1979
• Status: Expired due to Term

• Current Assignee: Williams Electronics Games Inc. (Scientific Games Corporation)
• Original Assignee: Williams Electronics Games Inc. (Scientific Games Corporation)
• Inventors: Pfeiffer, Randall R.
• Primary Examiner(s): Atkinson, Charles E.
• Assistant Examiner(s): KEMENY, EMANUEL
• Application Number:
  US06/028,079
• Time in Patent Office: 792 Days
• Field of Search: 179/1 SA, 179/1 SM, 179/1 SF, 84/1.01, 84/1.03, 84/1.17, 340/148, 340/692
• US Class Current: 704/258
• CPC Class Codes: G10H 7/002 using a common processing for different operations or calculations, and a set of microinstructions (programme) to control the sequence thereof
• CPC Class Codes: G10L 13/06 Elementary speech units used in speech synthesisers; Concatenation rules
• CPC Class Codes: G10L 19/00 Speech or audio signals analysis-synthesis techniques for redundancy reduction, e.g. in vocoders; Coding or decoding of speech or audio signals, using source filter models or psychoacoustic analysis in musical instruments G10H

Abstract

An electronic circuit is disclosed which is capable of producing synthesized sounds under the control of a microprocessor or other type computer. A plurality of switch inputs are provided whereby the sound to be produced can be selected. The processor, under program control, then generates such sounds utilizing one or more basic waveforms stored in a memory. These basic waveforms are modified in specified ways and then outputted through an I/O device to a digital to analog converter for application to an audio system. Eight input control lines to the microprocessor also feed an 8-input NAND gate, such that a momentary change of the normally-high control inputs will cause the NAND gate to activate an interrupt request.

Claims

1. A method of synthesizing sound comprising the steps of:

(a) storing in a processor memory data from which the sound waveforms are to be synthesized and a program for causing said processor to produce digital representations of the sound waveforms,

(b) executing selective portions of said program utilizing selected data depending upon the sound waveform desired, including the substeps of;

(i) providing data lines connected to said processor, the logic state of said lines being externally controlled to select the portions of said program executed and the data utilized,

(ii) detecting a change in the logic state of said data lines,

(iii) causing said processor to poll said data lines whenever a change is detected thereby to control the operation of said processor,

(c) converting said digital representation to corresponding analog sound waveforms,

(d) applying said analog sound waveforms to audio means to produce the desired sounds.

2. A sound synthesizing circuit comprising:

(a) a program controlled digital processor having an interrupt capability including a central processing unit, memory circuits having a program and data relating to the sounds to be produced stored therein, and an input/output (I/O) device,

(b) means for selecting the data utilized and the portions of the program in memory to be executed by said processor, said program causing said processor to produce a digital representation of a desired sound waveform, said selecting means including a plurality of externally controlled data lines connected to said I/O device, the logic state on each of said lines determining the data utilized and the portion of the program to be executed,

(c) interrupt signalling means connected to said data lines for detecting a change in the logic state of any one or more of said lines and providing an interrupt signal to said processor whereby said processor is caused to scan said lines to determine their logic states,

(d) a digital to analog (D/A) converter connected to said processor via said I/O device for converting said digital representation of a sound waveform to a corresponding analog waveform,

(e) audio means for receiving said analog waveform and producing sounds corresponding thereto.

3. The circuit according to claim 2 wherein said I/O device is a peripheral interface adapter having a plurality of I/O lines for communicating with said processor, a first set of said I/O lines being connected to said data lines to communicate the logic state of said data lines to said processor, a second set of said I/O lines being connected to said D/A converter to communicate the digital representation of the sound waveform to said converter.