EP0415237A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Active noise control apparatus for domestic appliance
Assignee: Toshiba Corp
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Filing: 1990-08-21
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Granted: —
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Expires: 2010-08-21
Abstract
Abstract An apparatus includes an electro-acoustic converter (22), a detector (23), a noise correlative signal generator (20), and an additional tone signal generator (26) in order to actively control noise generated by an electromagnetic machine (9), which noise is apt to externally leak from an opening (12) of a machine room (8) storing the electromagnetic machine (9) driven by an AC power supply. The electro-acoustic converter (22) applies a predetermined sound wave to the opening (12) of the machine room (8). The detector (23) essentially detects a frequency of an AC voltage waveform to be applied to the electromagnetic machine (9) driven by the AC power supply. The noise correlative signal generator (20) generates generating a signal correlative with an electromagnetic noise component included in noise generated by the electromagnetic machine (9) according to a detection signal from the detector (23). The additional tone signal generator (26) generates, according to an output signal from the noise correlative signal generator (20), an additional tone signal for causing the electro-acoustic converter (22) to apply a sound wave essentially having a phase opposite to and the same amplitude as those of the electromagnetic noise component at the opening (12) of the machine room (8).
Inventors
- 👤 Susumu C/O Intellectual Property Division Saruta
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-24 19:12
CPC Classifications
G; G10; G10K; G10K11/00; G10K11/16; G10K11/175; G10K11/178; G10K11/1787; G10K11/17873; G10K11/1785; G10K11/17853; F; F25; F25B; F25B2500/00; F25B2500/12; G10K2210/00; G10K2210/10; G10K2210/105; G10K2210/1054; G10K2210/109; G10K2210/30; G10K2210/301; G10K2210/3032; G10K2210/3045
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
194 words
An apparatus for actively controlling noise generated by an electromagnetic machine (9), which noise is apt to externally leak from an opening (12) of a machine room (8) storing said electromagnetic machine (9) driven by an AC power supply, said apparatus comprising: electro-acoustic conversion means (22) for applying a predetermined sound wave to the opening (12) of said machine room (8); characterized in that said apparatus further comprises: detection means (23) for essentially detecting a frequency of an AC voltage waveform to be applied to said electromagnetic machine (9) driven by said AC power supply; noise correlative signal generating means (20) for generating a signal correlative with an electromagnetic noise component included in noise generated by said electromagnetic machine (9) according to a detection signal from said detection means (23); and additional tone signal generating means (26) for generating, according to an output signal from said noise correlative signal generating means (20), an additional tone signal for causing said electro-acoustic conversion means (22) to apply a sound wave essentially having a phase opposite to and the same amplitude as those of the electromagnetic noise component at the opening (12) of said machine room (8).
Claim 2
Independent Claim
194 words
An apparatus for actively controlling noise generated by an electromagnetic machine (9), which noise is apt to externally leak from an opening (12) of a machine room (8) storing said electromagnetic machine (9) driven by an AC power supply, said apparatus comprising: electro-acoustic conversion means (22) for applying a predetermined sound wave to the opening (12) of said machine room (8); characterized in that said apparatus further comprises: detection means (23) for essentially detecting a frequency of an AC voltage waveform to be applied to said electromagnetic machine (9) driven by said AC power supply; noise correlative signal generating means (20) for generating a signal correlative with an electromagnetic noise component included in noise generated by said electromagnetic machine (9) according to a detection signal from said detection means (23); and additional tone signal generating means (26) for generating, according to an output signal from said noise correlative signal generating means (20), an additional tone signal for causing said electro-acoustic conversion means (22) to apply a sound wave essentially having a phase opposite to and the same amplitude as those of the electromagnetic noise component at the opening (12) of said machine room (8).
Claim 3
Dependent Claim
64 words
An apparatus according to claim 1, characterized in that said noise correlative component signal generating means (20) comprises: a frequency multiplier (24) for doubling the detection signal from said detection means (23); and a harmonic generator (25) for receiving an output signal from said frequency multiplier (24), and generating a fundamental wave of the output signal and a plurality of orders of harmonic signals.
Claim 4
Dependent Claim
29 words
An apparatus according to claim 2, characterized in that said detection means (23) includes a transformer (23a), a primary side of which is connected to said AC power supply.
Claim 5
Dependent Claim
27 words
An apparatus according to claim 3, characterized in that said frequency multiplier (24) includes a full-wave rectifier (24a) connected to a secondary side of said transformer (23a).
Claim 6
Dependent Claim
28 words
An apparatus according to claim 4, characterized in that said harmonic generator (25) comprises a pulsation circuit (25a, 25b) for pulsating an output from said full-wave rectifier (24a).
Claim 7
Dependent Claim
40 words
An apparatus according to claim 5, characterized in that said harmonic generator (25) includes an insulating circuit (25a) for insulating an output from said full-wave rectifier (24a) in an AC manner and supplying the output to said pulsation circuit (25b).
Claim 8
Dependent Claim
98 words
An apparatus according to claim 5, characterized in that said additional tone signal generating means comprises: a low-pass filter (26a) for low-pass filtering an output from said pulsation circuit (25a, 25b); an A/D converter (26b) for A/D-converting an output from said low-pass filter (26a); an FIR digital filter (26c) for filtering an output from said A/D converter (26b) to output a signal having transfer characteristics corresponding to the predetermined sound wave to be applied to the opening (12) of said machine room (8); and a D/A converter (26d) for D/A-converting an output signal from said FIR digital filter.
Claim 9
Dependent Claim
45 words
An apparatus according to claim 7, characterized in that said additional tone signal generating means further comprises: another low-pass filter (26e) for low-pass filtering an output from said D/A converter (26d); and an amplifier (26f) for amplifying an output from said another low-pass filter (26e).
Claim 10
Independent Claim
188 words
An apparatus for actively controlling noise generated by an electromagnetic machine (9), which noise is apt to externally leak from an opening (12) of a machine room (8) storing said electromagnetic machine (9) driven by an AC power supply, said apparatus comprising: electro-acoustic conversion means (22) for applying a predetermined sound wave to the opening of said machine room (8); characterized in that said apparatus further comprises: detection means (31) for detecting an AC voltage waveform and an AC current waveform to be applied to said electromagnetic machine (9) driven by said AC power supply; noise correspondence signal generating means (34) for generating a signal having a spectrum corresponding to noise generated by said electromagnetic machine (9) according to a detection signal from said detection means (31); and additional tone signal generating means (43) for generating, according to an output signal from said noise correlative signal generating means (34), an additional tone signal for causing said electro-acoustic conversion means (22) to apply a sound wave essentially having a phase opposite to and the same amplitude as those of the noise at the opening of said machine room (8).
Claim 11
Independent Claim
188 words
An apparatus for actively controlling noise generated by an electromagnetic machine (9), which noise is apt to externally leak from an opening (12) of a machine room (8) storing said electromagnetic machine (9) driven by an AC power supply, said apparatus comprising: electro-acoustic conversion means (22) for applying a predetermined sound wave to the opening of said machine room (8); characterized in that said apparatus further comprises: detection means (31) for detecting an AC voltage waveform and an AC current waveform to be applied to said electromagnetic machine (9) driven by said AC power supply; noise correspondence signal generating means (34) for generating a signal having a spectrum corresponding to noise generated by said electromagnetic machine (9) according to a detection signal from said detection means (31); and additional tone signal generating means (43) for generating, according to an output signal from said noise correlative signal generating means (34), an additional tone signal for causing said electro-acoustic conversion means (22) to apply a sound wave essentially having a phase opposite to and the same amplitude as those of the noise at the opening of said machine room (8).
Claim 12
Dependent Claim
134 words
An apparatus according to claim 9, characterized in that said noise correspondence signal generating means (34) comprises: electromagnetic noise correspondence signal generating means (35, 36) for generating a signal having a spectrum corresponding to an electromagnetic noise component included in the noise according to a detection signal associated with the AC voltage waveform from said detection means (31); rotational noise correspondence signal generating means (37 to 40) for generating a signal having a spectrum corresponding to a rotational noise component included in the noise according to a detection signal associated with the AC current waveform from said detection means (31); and synthesizing means (42) for synthesizing an output signal from said electromagnetic noise correspondence signal generating means (35, 36) and an output signal from said rotational noise correspondence signal generating means (37 to 40).
Claim 13
Dependent Claim
67 words
An apparatus according to claim 10, characterized in that said electromagnetic noise correspondence signal generating means (35, 36) includes a frequency multiplier (35) for doubling the detection signal associated with the AC voltage waveform from said detection means (31), and a harmonic generator (36) for distorting an output signal from said frequency multiplier (35) to generate a harmonic signal corresponding to the spectrum of the electromagnetic noise.
Claim 14
Dependent Claim
95 words
An apparatus according to claim 11, characterized in that said rotational noise correspondence signal generating means (37 to 40) includes a low-pass filter (37) for low-pass filtering the detection signal associated with the AC current waveform from said detection means (31), an adder (39) for calculating a difference between an output signal from said low-pass filter (37) and the detection signal associated with the AC voltage waveform, and another harmonic generator (40) for distorting an output signal from said adder (39) to generate a harmonic signal corresponding to a spectrum component of the rotational noise.
Claim 15
Dependent Claim
63 words
An apparatus according to claim 12, characterized in that said noise correspondence signal generating means (34) further includes an AM modulator (41) for amplitude-modulating an output signal from said harmonic generator (36) with an output signal from said adder (39), generating a signal corresponding to a modulated noise component included in the noise, and supplying the generated signal to said synthesizing means (42).
References Cited (Backward Citations)
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