Transducer for bioacoustic signals
First Claim
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1. A transducer assembly for transducing bioacoustic signals, comprising:
- a transducer element having a front side and a rear side;
a housing, the housing subject to ambient noise and comprising a surface surrounding the front side of the transducer element, the transducer element and the surrounding surface of the housing situated to establish intimate coupling with a surface of a body part during use, the body part surface defining a source of the bioacoustic signals; and
communicating an ambient noise through an opening in the housing and to the rear side of the transducer element and receiving ambient noise at the front side of the transducer element when the housing establishes intimate coupling with the body part surface during use; and
thereby reducing ambient noise andan ambient noise suppression arrangement comprising a selected area ratio of an effective area of the transducer element sd relative to an area of the surrounding surface of the housing sh, wherein the effective area of the transducer element sd is less than 50% of the surrounding surface area sh and the selected area ratio provides for increased ambient noise suppression within a frequency range associated with the bioacoustic signals.
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Accused Products
Abstract
In well-known electronic stethoscopic transducers the sensitive element is influenced by signals transmitted via the skin, and the rear side is enclosed in a housing to prevent airborne noise from reaching the sensitive element. According to the invention, an improved signal-to-noise ratio is obtained by letting the transducer be a piezoelectric transflexural diaphragm in contact with the skin, the rear side of the diaphragm communicating with the surrounding air via an acoustical network, thereby receiving airborne noise which acts to counteract the influence of noise coming from the skin.
22 Citations
12 Claims
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1. A transducer assembly for transducing bioacoustic signals, comprising:
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a transducer element having a front side and a rear side; a housing, the housing subject to ambient noise and comprising a surface surrounding the front side of the transducer element, the transducer element and the surrounding surface of the housing situated to establish intimate coupling with a surface of a body part during use, the body part surface defining a source of the bioacoustic signals; and
communicating an ambient noise through an opening in the housing and to the rear side of the transducer element and receiving ambient noise at the front side of the transducer element when the housing establishes intimate coupling with the body part surface during use; and
thereby reducing ambient noise andan ambient noise suppression arrangement comprising a selected area ratio of an effective area of the transducer element sd relative to an area of the surrounding surface of the housing sh, wherein the effective area of the transducer element sd is less than 50% of the surrounding surface area sh and the selected area ratio provides for increased ambient noise suppression within a frequency range associated with the bioacoustic signals. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A transducer assembly for transducing bioacoustic signals, comprising:
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a skin coupling surface comprising a transducer element and having a front side and a rear side; a housing, the housing subject to ambient airborne noise and comprising a surface surrounding the front side of the transducer element, the transducer element and the surrounding surface of the housing situated to establish intimate coupling with a surface of a body part during use, the body part surface defining a source of the bioacoustic signals; and an ambient noise suppression arrangement configured to suppress ambient airborne noise coupled to the rear side of the skin coupling surface and ambient airborne noise coupled to an opening of the housing and the front side of the skin coupling surface, the ambient noise suppression arrangement configured to upwardly shift a transducer assembly resonance notch beyond an upper frequency limit of a frequency range associated with particular bioacoustic signals wherein the ambient noise suppression arrangement comprises a selected area ratio of an effective area of the transducer element relative to an area of the surrounding surface of the housing. - View Dependent Claims (8)
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9. A method of transducing bioacoustic signals, comprising:
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providing a transducer assembly comprising a housing and a transducer element having a front side and a rear side, the housing comprising a surface surrounding the front side of the transducer element, the transducer element and the surrounding surface of the housing situated to establish intimate coupling with a surface of a body part during use, the body part surface defining a source of the bioacoustic signals; communicating ambient noise through an opening in the housing and to the back side of the transducer element; receiving ambient noise at the front side of the transducer element when the housing establishes intimate coupling with the body part surface during use; and reducing ambient noise influencing the transducer element by upwardly shifting a transducer assembly resonance notch beyond an upper frequency limit of a frequency range associated with particular bioacoustic signals; wherein reducing ambient noise influencing the transducer element comprises providing a selected area ratio of an effective area of the transducer element relative to an area of the surrounding surface of the housing, wherein the effective area of the transducer element is less than 50% of the surrounding surface area. - View Dependent Claims (10, 11, 12)
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Specification