Apparatus for mounting a unidirectional microphone in a hands-free telephone subset

• US 4,885,773 A
• Filed: 01/09/1987
• Issued: 12/05/1989
• Est. Priority Date: 01/09/1987
• Status: Expired due to Fees

• Current Assignee: Alcatel NV (Nokia Corporation)
• Original Assignee: Alcatel NV (Nokia Corporation)
• Inventors: Stottlemyer, William O., Woodward, Steven J.
• Primary Examiner(s): NOT, DEFINED
• Assistant Examiner(s): Vaas, Randall S.
• Application Number:
  US07/001,781
• Time in Patent Office: 1,061 Days
• Field of Search: 379/388, 379/389, 379/390, 379/420, 379/432, 381/58, 381/88, 381/87, 381/92, 381/94, 381/122, 381/155, 381/159, 381/169, 381/188, 381/191, 381/205
• US Class Current: 379/420.03
• CPC Class Codes: H04M 1/62 Constructional arrangements
• CPC Class Codes: H04M 9/08 Two-way loud-speaking telephone systems with means for conditioning the signal, e.g. for suppressing echoes for one or both directions of traffic

Abstract

There is disclosed a shroud and housing assembly which is attached to or forms an integral part of the front sidewall of a hands-free telephone subset. The shroud assembly contains a trough which is directed along the length thereof and which terminates at one end in a housing for a microphone or similar device. The shroud has a flanged wall integrally secured to the microphone housing for accommodating an electret condenser microphone. The shroud section is further supported by means of upstanding posts which are connected to the sides of the or flange by means of thin webs. The posts and webs act to strengthen the housing while further providing support to prevent undesired vibrations which emanate from a loudspeaker contained within the subset housing from coupling to the accommodated microphone. The reinforced housing minimizes the coupling of mechanical borne vibrations between the subsets loudspeaker and the microphone. Partial slots are also placed around the outer edge of the shroud about the area which contains the microphone housing. These slots have little or no effect on acoustic signals arriving from the front of the subset but signals arriving from the rear enter both the slots and the front cavity opening. In this manner, the microphone discriminates against certain sounds which are cancelled out while preserving the unidirectional characteristics of the microphone.

Claims

1. Apparatus for accommodating a unidirectional microphone for use in isolating unwanted sound waves from said microphone which unwanted sound waves emanate from an additional sound source associated with a communication housing, said communication housing being a box-like configuration having a top and bottom surface oriented in the horizontal plane with sidewalls in the vertical plane, with said additional sound source positioned on the top surface with said communication housing enabling a user to transmit voice via said microphone and to listen via said additional sound source, comprising:

a microphone housing having an internal hollow with an extending annular flange directed from said microphone housing and communicating with said hollow and of a smaller diameter than said microphone housing and having an internal annular flange within said extending annular flange against which the back surface of said microphone abuts to enable said microphone to extend into said hollow of said microphone housing to accurately position the diaphragm of said microphone parallel to the vertical plane with respect to said hollow and a series of slots located about a portion of the periphery of said microphone housing and spaced apart one from the other with another portion of the periphery of said housing being solid,

means for mounting said microphone housing on a first vertical sidewall of said communication housing such that said solid peripheral portion is positioned to maximumly reject undesired sound waves from said additional source with said slots serving to pass said undesired sound waves to enable cancellation of the same with similar sound waves impinging upon a responsive surface of said diaphragm, and

an elongated shroud member coupled to said microphone housing and extending from the solid peripheral portion thereof and positioned along said first vertical sidewall parallel to the horizontal plane to add mass for reducing mechanical vibrations which would otherwise adversely affect microphone operation.

2. The apparatus according to claim 1 wherein said shroud member has an upstanding peripheral flange extending from the surface thereof and contiguous with the surface of said microphone housing.

3. Apparatus for accommodating a unidirectional microphone for use in isolating sound waves from said microphone which sound waves emanate from an additional sound source remote from said microphone and associated with a communication system housing in which a user communicates via said microphone and listens via said additional sound source, comprising:

an elongated shroud member having a U-shaped channel cross-section with a bottom planar member having an extending flange about the outer peripheral edge completely surrounding said bottom planar member;

a microphone housing integrally formed with said shroud member and having an internal hollow for accommodating said microphone and having an extending annular section which extends above said flange and directed at an angle so that when said shroud is positioned with said planar member oriented with respect to the vertical plane said annular section has a main axis parallel to the horizontal plane, with said shroud and housing acting to selectively dissipate said waves from said additional source, and to enable an accommodated microphone to have its diaphragm parallel to the vertical plane.

5. The apparatus according to claim 3 wherein said microphone housing includes a plurality of slots about the periphery thereof to selectively couple said waves to the accommodated microphone.

6. The apparatus according to claim 5 wherein said microphone housing is circular and said slots are positioned at ninety degree spaced intervals about the periphery of said circular microphone housing.

7. The apparatus according to claim 3 wherein said extending flange is at a given angle with respect to said bottom planar member with a first section of said flange extending a greater distance from said bottom member than a second section of said flange.

8. The apparatus according to claim 3 further including:

at least one extending post positioned on said planar member and extending beyond said flange and operative to provide mechanical support to said shroud while serving to attenuate sound waves.

9. The apparatus according to claim 3 wherein said unidirectional microphone is an electret microphone having a cardioid pattern.

4. Apparatus for accommodating a unidirectional microphone for use in isolating sound waves from said microphone which sound waves emanate from an additional sound source remote from said microphone and associated with a communication system housing in which a user communicates via said microphone and listens via said additional sound source, comprising:

an elongated shroud member having a U-shaped channel cross-section with a bottom planar member having an extending flange about the outer peripheral edge completely surrounding said bottom planar member; and

a microphone housing integrally formed with said shroud member and having an internal hollow for accommodating said microphone and having an extending annular section which extends above said flange and directed at an angle so that when said shroud is positioned with said planar member oriented with respect to the vertical plane said annular section has a main axis parallel to the horizontal plane, with said shroud and housing acting to selectively dissipate said waves from said additional source, and to enable an accommodated microphone to have its diaphragm parallel to the vertical plane,

wherein said communications system is a hands-free telephone subset with said additional source being a loudspeaker mounted on said hands-free telephone subset with the central axis of the loudspeaker cone oriented essentially vertical.

10. Apparatus for accommodating a unidirectional microphone for use in isolating interfering sound waves from said microphone which sound waves emanate from an additional sound source positioned in a horizontal plane associated with a combustion system housing of the type enabling a user to speak via said microphone and to listen via said additional source, comprising:

an elongated shroud member having a planar bottom surface generally of a rectangular configuration and having along a first long side an extending flange of a given height, with a second long side opposite said first long side having an extending flange of a lesser height with a first short side at one end having a tapered flange wherein said bottom surface is oriented at a given angle when said elongated member is placed on a horizontal surface supporting said second long side;

a hollow microphone housing section located proximate a second short side opposite from said first short side, said hollow microphone housing having a surrounding wall bridging between said extending flanges and co-extensive in height with each of said extending flanges where adjacent, and a central projecting circular flange extending from said wall and oriented at said given angle for accommodating a unidirectional microphone, with said hollow microphone housing section having parallel apertures on the top, bottom and side surfaces which apertures operate in conjunction with said shroud to attenuate sound waves emanating from said additional sound source.

11. The apparatus according to claim 10 wherein said unidirectional microphone is an electret condenser microphone.

12. The apparatus according to claim 10 wherein said communication system housing is a hands-free telephone subset, having said shroud positioned on a front side surface, with said additional sound source being a loudspeaker positioned on a top surface at about said given angle with respect to the horizontal plane.

13. The apparatus according to claim 10 wherein said elongated shroud member is of a length at least five times greater than its width.