| 摘要 |
1,002,983. Loud-speaking telephone sets. H. PEIKER. Nov. 8, 1961 [Nov. 12, 1960], No. 39921/61. Heading H4J. A loud-speaking telephone instrument includes a loud-speaker and a unidirectional microphone coaxially mounted, the microphone being so disposed relatively to the loud-speaker that it presents an aspect of minimum response opposed to an aspect of the loud-speaker from which maximum sound radiation occurs. The microphone may have a kidney-shaped or clubshaped directional characteristic. A unidirectional microphone 1 (Fig. 3) is secured in front of a loud-speaker 6, the microphone 1 having its direction of minimum response towards the loud-speaker 6. The microphone 1 is carried by supports 12, 13 which enable it to be moved from the working position (as shown) to a position in which it is close up against the loud-speaker. Movement is effected by operation of a key 10 which also operates a switch 11 for the current supply to an associated amplifier (not shown). A sound screen 15 is attached to the microphone 1 or to the loud-speaker 6 or to the supports 12, 13. In an alternative arrangement (Fig. 4, not shown) the microphone is carried on a single lever and may be swung, by operation of a key, from a rest position close up against the front of the loud-speaker, or within the cavity of the loudspeaker cone, to a working position spaced further from the loud-speaker. A sound screen of conical form may be attached to a lever which swings simultaneously with the microphone lever. |
