Electronic sound source having reduced spurious emissions

• US 5,789,690 A
• Filed: 11/29/1995
• Issued: 08/04/1998
• Est. Priority Date: 12/02/1994
• Status: Expired due to Term

• Current Assignee: Dropbox, Inc.
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Suzuoki, Masakazu, Furuhashi, Makoto
• Primary Examiner(s): Shoop, Jr., William M.
• Assistant Examiner(s): Fletcher, Marlon T.
• Application Number:
  US08/564,560
• Time in Patent Office: 979 Days
• Field of Search: 84/605-606, 84/630, 84/633, 84/665, 84/620
• US Class Current: 84/633
• CPC Class Codes: A63F 13/10 Control of the course of the game, e.g. start, progess, end
• CPC Class Codes: A63F 13/45 Controlling the progress of the video game
• CPC Class Codes: A63F 2300/6063 for sound processing
• CPC Class Codes: G10H 2210/026 for games, e.g. videogames
• CPC Class Codes: G10H 2230/041 Processor load management, i.e. adaptation or optimization of computational load or data throughput in computationally intensive musical processes to avoid overload artifacts, e.g. by deliberately suppressing less audible or less relevant tones or decreasing their complexity
• CPC Class Codes: G10H 2250/595 ADPCM [adaptive differential pulse code modulation]
• CPC Class Codes: G10H 7/02 in which amplitudes at successive sample points of a tone waveform are stored in one or more memories
• CPC Class Codes: G10K 15/02 Synthesis of acoustic waves synthesis of speech G10L13/00

Abstract

An electronic sound source comprises an adder which calculates a sum of volume data and differential volume data in response to each clock signal supplied at equal intervals of time and transfers it to a limiter and a volume register. The sum volume data is then limited to a predetermined value by the limiter and passed across a volume register to a volume controller where it is multiplied by an output of a mute processor.

Claims

1. A sound source device comprising:

a waveform buffer for storage of a waveform data;

a pitch converter means for reading out the waveform data from the waveform buffer and changing a pitch of the waveform data in accordance with pitch data;

an amplitude memory for holding amplitude data;

a differential amplitude memory for storing differential amplitude data;

a level modifying means for changing the amplitude data held in the amplitude memory based on the differential amplitude data held in the differential amplitude memory to provide an adjusted amplitude data; and

a level controller for receiving an output of the pitch converter and adjusting an amplitude level of the output from the pitch converter based on the adjusted amplitude data to provide a gradually adjusted output.

2. The sound source device of claim 1, wherein a level of the adjusted output changes gradually.

3. The sound source device of claim 2, wherein a level of the adjusted output changes in accordance with a linear function.

4. The sound source device of claim 2, wherein a level of the adjusted output changes in accordance with an exponential function.

5. The sound source device of claim 1, wherein the level controller comprises a further memory means for storing further amplitude data and an adder for adding the further amplitude data to the differential amplitude data.

6. The sound source device of claim 1, further comprising a means for reverberating the adjusted output.

7. The sound source device of claim 1, further comprising a means for sensing a load on a CPU associated with the sound source device.

9. The method of producing an audio signal of claim 6, wherein the adjusted output changes gradually.

10. The method of producing an audio signal of claim 6, wherein the adjusted output changes in accordance with a linear function.

11. The method of producing an audio signal of claim 6, wherein the adjusted output changes in accordance with an exponential function.

8. A method of producing an audio signal comprising the steps of:

providing waveform data;

changing a pitch of the waveform data to provide a pitch converted output;

storing amplitude data in an amplitude memory;

adjusting an amplitude level of the amplitude data in the amplitude memory based on differential amplitude data held in a differential amplitude memory to provide adjusted amplitude data; and

adjusting a level of the pitch converted output based on the adjusted amplitude data held in an amplitude memory to provide a gradually adjusted output.