公开(公告)号：US5903655A

公开(公告)日：1999-05-11

申请号：US734796

申请日：1996-10-23

申请人： Peter T. Salmi ,  Thomas A. Scheller

发明人： Peter T. Salmi ,  Thomas A. Scheller

IPC分类号： H04R25/00

CPC分类号： H04R25/356 ,  H04R2225/41 ,  H04R25/502

摘要： A hearing aid circuit using an averaging detector and a plurality of time constants to produce a compression control signal to control the gain of a compression amplifier which compresses an input signal when the averaging detector signal exceeds a predetermined threshold. The compression control signal has an attack and release time. The release time of the compression control signal is proportional to the duration of time during which the averaging signal's amplitude exceeds the predetermined threshold level. The release has a variable recovery rate. The recovery rate is relatively fast during an initial portion of the release time and relatively slower during the remaining portion of the release time. The hearing aid circuit may also use a volume control to adjust the gain of the signal produced by the compression amplifier without adjusting the gain of the signal produced by a linear amplifier to provide volume control for soft sounds independent of loud sounds.

摘要翻译： 一种助听器电路，使用平均检测器和多个时间常数来产生压缩控制信号以控制当平均检测器信号超过预定阈值时压缩输入信号的压缩放大器的增益。 压缩控制信号具有攻击和释放时间。 压缩控制信号的释放时间与平均信号的振幅超过预定阈值水平的持续时间成比例。 该版本具有可变的恢复速率。 恢复速率在释放时间的初始部分相对较快，而在释放时间的剩余部分期间恢复速率相对较慢。 助听器电路还可以使用音量控制来调节由压缩放大器产生的信号的增益，而不调节由线性放大器产生的信号的增益，以提供独立于大声的软声音量控制。

公开(公告)号：USD389153S

公开(公告)日：1998-01-13

申请号：US64064

申请日：1996-12-20

申请人： Eugene D. Litzau

设计人： Eugene D. Litzau

公开(公告)号：USD386764S

公开(公告)日：1997-11-25

申请号：US53220

申请日：1996-04-17

申请人： Thomas Lake

设计人： Thomas Lake

公开(公告)号：US5639152A

公开(公告)日：1997-06-17

申请号：US661631

申请日：1996-06-11

申请人： Brian Nelson

发明人： Brian Nelson

IPC分类号： G03B21/00 ,  G03B21/132 ,  G03B21/28 ,  G03B21/30

CPC分类号： G03B21/132 ,  G03B21/28 ,  G03B21/30

摘要： A portable LCD-type projector for images on a viewing surface such as a projection screen. The projector includes a housing having top, bottom, front and back panels hingedly connected in a parallelogram. The housing panels are movable from a first, generally flat folded position to a second, open position in which the top and bottom panels are generally horizontal and the front and back panels are oriented at a generally 45.degree. angle. The projector includes a light source, a lens, and an LCD or similar image-generating panel. The LCD panel is carried in a location optically between the light source and the lens. The LCD panel is movable from a first, generally horizontal stored position to a second, generally vertical operating position. Mirrors are provided for directing light emitted by the light source through the LCD panel and the lens for projection on a projection screen.

摘要翻译： 一种用于在诸如投影屏幕的观察表面上的图像的便携式LCD型投影仪。 投影仪包括具有以平行四边形铰接连接的顶部，底部，前部和后部面板的壳体。 外壳面板可以从第一，大致平坦的折叠位置移动到第二打开位置，在该位置中，顶板和底板大致水平，并且前面板和后面板以大致45度的角度定向。 该投影仪包括光源，透镜和LCD或类似的图像生成面板。 LCD面板在光源和透镜之间的光学位置上携带。 LCD面板可从第一，大致水平的储存位置移动到第二，大致竖直的操作位置。 反射镜用于引导光源发射的光通过LCD面板和透镜，用于投影在投影屏幕上。

公开(公告)号：USD368719S

公开(公告)日：1996-04-09

申请号：US22726

申请日：1994-05-11

申请人： James Luther

设计人： James Luther

公开(公告)号：USD345981S

公开(公告)日：1994-04-12

申请号：US903620

申请日：1992-06-24

申请人： Jonathan C. Burke

设计人： Jonathan C. Burke

公开(公告)号：USD333137S

公开(公告)日：1993-02-09

申请号：US685560

申请日：1991-04-12

申请人： Jonathan C. Burke

设计人： Jonathan C. Burke

公开(公告)号：US5182774A

公开(公告)日：1993-01-26

申请号：US555990

申请日：1990-07-20

申请人： Terrance R. Bourk

发明人： Terrance R. Bourk

IPC分类号： A61F11/14 ,  H04R1/10

CPC分类号： H04R1/1083 ,  A61F2011/145

摘要： A headset for acoustic reproduction of an electronic signal which electronic signal is representative of the summation of a desired audio signal and an anti-noise signal. The headset includes a headband, an earcup mounted to the headband, a driver mounted within the earcup which receives and acoustically reproduces the electronic signal, a directional microphone which detects and transduces the acoustical pressure within the earcup cavity, means for generating the anti-noise signal from the microphone signal, and a positioning member for mounting the microphone to the earcup in a position so that the microphone is acoustically coupled to the driver. The microphone is oriented so that its vented or open face is pointing towards the driver. If the driver is provided with an inner dome portion and an outer annulus portion the microphone is positioned by its attachment to a grille plate extending across the driver, the microphone being mounted to the grille plate on a side opposite the driver. The grille plate includes a plurality of apertures, at least one of which is positioned proximate the center of the driver with the microphone mounted across that aperture so that the microphone is acoustically coupled to the dome portion and acoustically isolated from the outer annulus portion.

摘要翻译： 一种用于电子信号的声音再现的耳机，其电子信号表示所需音频信号和抗噪声信号的总和。 头戴式耳机包括头带，安装在头带上的耳罩，安装在耳罩内的驱动器，用于接收并声学地再现电子信号;定向麦克风，其检测和转换耳罩腔内的声压;用于产生抗噪声的装置 来自麦克风信号的信号，以及用于将麦克风安装到耳罩的定位构件，使得麦克风声学耦合到驾驶员。 麦克风被定向成使得其通风或开放的面朝向驾驶员。 如果驱动器设置有内圆顶部分和外环形部分，则麦克风通过其附接定位在延伸穿过驱动器的格栅板上，麦克风在与驱动器相对的一侧安装到格栅板。 格栅板包括多个孔，其中至少一个孔邻近驱动器的中心定位，麦克风安装在穿过该孔的位置上，使得麦克风声耦合到圆顶部分并与外环形部分隔离。

公开(公告)号：US5097224A

公开(公告)日：1992-03-17

申请号：US684020

申请日：1991-04-11

申请人： Peter L. Madaffari ,  Michael J. Wurtz

发明人： Peter L. Madaffari ,  Michael J. Wurtz

IPC分类号： H03F3/185 ,  H04R25/00

CPC分类号： H03F3/1855 ,  H03F2200/03 ,  H03F2200/372 ,  H04R19/016 ,  H04R25/00

摘要： An audio frequency amplification circuit for use with low level, high impedance signal sources, such as a miniature electret microphone, particularly useful where the power supply range is variable or may be limited to a single cell. The preferred embodiments of the circuit include a field effect transistor preamplifier stage operating as a voltage follower which is biased by a first and second impedance network coupled to the gate electrode of the FET transistor. A first impedance network is coupled between the power source terminals to provide a floating bias point. A second, high impedance network comprising (in one embodiment) a pair of parallel, reverse oriented diodes and a high impedance resistor is coupled between the bias point and the gate terminal of the transistor. In a further embodiment, the first impedance network comprises series connected high impedance resistors, and the second impedance network includes only the parallel, reverse oriented diodes. In either embodiment, extremely low capacitance elements may be coupled across the high impedance resistors, the elements preferably comprising stray capacitance from circuit conductor layout. Such source-follower biasing networks provides high input impedance and extended dynamic range without introducing noise or distortion. The audio frequency amplification circuit is preferably used as the preamplifier stage of a miniature electret microphone of extremely low source capacitance and mounted within the microphone in close proximity to the electret. Such a miniaturized, wide dynamic range microphone is especially adapted for use mounted on acoustic or electric musical instruments.

摘要翻译： 一种用于低电平，高阻抗信号源的音频放大电路，例如微型驻极体麦克风，其中电源范围是可变的或者可以限于单个电池，特别有用。 该电路的优选实施例包括作为电压跟随器工作的场效应晶体管前置放大器级，其被耦合到FET晶体管的栅电极的第一和第二阻抗网络偏置。 第一阻抗网络耦合在电源端子之间以提供浮动偏置点。 包括（在一个实施例中）一对并联的反向取向二极管和高阻抗电阻器的第二高阻抗网络耦合在该晶体管的偏置点和栅极端子之间。 在另一实施例中，第一阻抗网络包括串联连接的高阻抗电阻器，并且第二阻抗网络仅包括并行的反向取向二极管。 在任一实施例中，极低电容元件可跨越高阻抗电阻耦合，元件优选地包括来自电路导体布局的寄生电容。 这种源极跟随器偏置网络提供高输入阻抗和扩展的动态范围，而不引入噪声或失真。 音频放大电路优选地用作极低源极电容的微型驻极体麦克风的前置放大器级，并且安装在靠近驻极体的麦克风内。 这种小型化，宽动态范围的麦克风特别适用于安装在声学或电子乐器上。

公开(公告)号：US4727585A

公开(公告)日：1988-02-23

申请号：US934125

申请日：1986-11-24

申请人： Dean W. Flygstad

发明人： Dean W. Flygstad

IPC分类号： H04R1/10 ,  H04M1/05

CPC分类号： H04R5/0335

摘要： Apparatus for adjustably varying the tension intermediate the downwardly depending ends of a spring headband in a headset includes a longitudinally extending spring member having an arcuate shape and radius less than the intermediate portion of the headband, that is disposed on the top of the intermediate portion of the headband and stationarily connected to the headband at one end, a tension adjusting slider is disposed around the headband and the spring member for longitudinal movement so that the tension intermediate the lower ends of the headband is varied as the slider is repositioned.

摘要翻译： 用于可调节地改变耳机中的弹簧头带的向下悬垂端的张力的装置包括：纵向延伸的弹簧构件，其具有小于头带中间部分的弓形和半径，该弹性构件设置在头带的中间部分的顶部 头带并且在一端固定地连接到头带，张力调节滑块设置在头带周围和弹簧构件周围以用于纵向运动，使得当头部带的下端之间的中间张力随着滑块被重新定位而改变。