# US 9,438,362 B2 · Audio mixing device, method thereof, and electronic device

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 9,438,362 B2
- Document ID: US9438362B2
- Status: Granted
- Kind: B2
- Application number: 13/371,752
- Filed: 2012-02-13
- Published: 2012-08-23
- Granted: 2016-09-06
- Earliest claimed: 2011-02-22
- Assignees: Ricoh Company, Ltd.
- Applicants: Yukihiro Imai
- Inventors: Yukihiro Imai
- Web page: https://patentgrep.com/patent/US9438362B2

## CPC

- H04H 60/04: Studio equipment; Interconnection of studios
- H03F 3/217: Class D power amplifiers; Switching amplifiers
- H03F 2200/331: Sigma delta modulation being used in an amplifying circuit
- H03F 2200/339: Pulse amplitude modulation being used in an amplifying circuit
- H03F 2200/345: Pulse density modulation being used in an amplifying circuit
- H03F 2200/351: Pulse width modulation being used in an amplifying circuit
- Y02D 30/70: in wireless communication networks
- H04H: BROADCAST COMMUNICATION (multiplex communication H04J; pictorial communication aspects of broadcast systems H04N)
- H03F: AMPLIFIERS
- Y02D: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE

## Abstract

An audio mixing device includes: an adder that adds a plurality of PDM signals each converted from a plurality of digital audio signals; a D/A converter that performs D/A conversion on a digital audio signal outputted from the adder and outputs an analog audio signal; and a synchronization device that is provided prior to the adder, and that synchronizes each of a plurality of digital signals with one another by use of the same predetermined synchronization timing signal and outputs each of them to the adder.

## Claims

### Claim 1

An audio mixing device, comprising:
a plurality of pulse density modulation (PDM) signal generators that receive a plurality of respective digital audio signals and perforin pulse density modulation (PDM) on the received digital audio signals to generate a plurality of respective PDM signals;
a synchronization device that synchronizes each of the plurality of PDM signals with one another by use of a same predetermined synchronization timing signal, to generate a plurality of respective synchronized PDM signals;
an adder that adds the plurality of synchronized PDM signals to generate a digital audio signal; and
a D/A converter that performs D/A conversion on the digital audio signal generated by the adder, to generate an analog audio signal.

### Claim 2 (depends on 1)

An electronic device comprising:
the audio mixing device according to claim 1.

### Claim 3

An audio mixing method, performed by an audio mixing device, the method comprising:
(a) performing pulse density modulation (PDM) on a plurality of digital audio signals to generate a plurality of respective PDM signals;
(b) synchronizing each of the plurality of PDM signals with one another by use of a same predetermined synchronization timing signal, to generate a plurality of respective synchronized PDM signals;
(c) adding, by the audio mixing device, the plurality of synchronized PDM signals to generate a digital audio signal; and
(d) performing, by the audio mixing device, D/A conversion on the digital audio signal that was generated in (c), to generate an analog audio signal.