公开(公告)号：US5818672A

公开(公告)日：1998-10-06

申请号：US917118

申请日：1997-08-25

Applicant: Thomas C. Hilbe

Inventor： Thomas C. Hilbe

IPC: H04B15/00 ,  H05K9/00 ,  H02H9/08

CPC classification number: H04B15/00 ,  H05K9/0064

Abstract: Apparatus and process are provided for suppressing interference caused by ground loop currents associated with two A.C. power-line operated electrical/electronic equipment units, such as an audio source and an amplifier, where typically the ground loop includes a shielded signal cable interconnecting the two equipment units. A signal representing current sensed from a selected region of the ground loop is amplified and injected into a second region of the ground loop as a counteractive current having polarity opposite that of the original ground loop current, thus tending to nullify the interference. The amplification may be made adjustable for optimal suppression. Ground loop current may be sensed by a sensing transformer coupled to the loop or by a pair of sense lines, connected to selected nodes in the ground loop such as respective ground terminals of the two equipment units, and providing the sensed signal to differential amplifier inputs. A counteractive current, delivered by the amplifier output, is coupled to the ground loop inductively by means of a driving transformer having a closed ferro-magnetic core surrounding the selected portion of the ground loop, such as the grounding conductor of a line cord of one of the equipment units or the shielded signal cable interconnecting the two equipment units.

Abstract translation: 提供了用于抑制与两个AC电力线路操作的电气/电子设备单元（例如音频源和放大器）相关联的接地回路电流引起的干扰的装置和过程，其中通常地面回路包括互连两个设备的屏蔽信号电缆 单位。 表示从接地环路的选定区域感测的电流的信号被放大并被注入到具有与原始接地回路电流相反极性的反电流的接地回路的第二区域中，因此倾向于使干扰无效。 为了最佳抑制，放大可以调节。 接地回路电流可以由耦合到环路的感测变压器或连接到接地回路中的选定节点（例如两个设备单元的各个接地端子）的一对感测线路感测，并将感测到的信号提供给差分放大器输入 。 由放大器输出传递的抗电流通过驱动变压器感应地耦合到接地回路，驱动变压器具有围绕接地回路的选定部分的封闭铁磁芯，例如一根线的电线的接地导体 的设备单元或连接两个设备单元的屏蔽信号电缆。

公开(公告)号：US5724434A

公开(公告)日：1998-03-03

申请号：US744398

申请日：1996-11-07

Applicant: Daniel C. Myers

Inventor： Daniel C. Myers

IPC: H03G9/02 ,  H03G3/00

CPC classification number: H03G9/02

Abstract: A voltage controlled audio attenuator, of particular benefit in audio limiters, is created by configuring a nearly-balanced four-resistor bridge such that at least one of the branch resistors is implemented as a magnetoresistive element, located in a variable magnetic field, typically generated by a coil energized by current from an electronic driver which is made controllable from a DC control voltage, which is thus enabled to control the attenuation of the bridge. A suitable feedback processing circuit, receiving input from the bridge output and producing the DC control voltage in a predetermined dynamic relationship, forms the feedback branch of an automatic loop, thus the voltage-controlled attenuator is utilized as a key element of an audio limiter.

Abstract translation: 在音频限制器中特别有益的电压控制音频衰减器通过配置几乎平衡的四电阻桥而产生，使得至少一个分支电阻器被实现为位于可变磁场中的磁阻元件，通常产生 通过由电子驱动器的电流激励的线圈，其由DC控制电压控制，从而能够控制桥的衰减。 接收来自桥输出的输入并以预定的动态关系产生DC控制电压的合适的反馈处理电路形成自动回路的反馈分支，因此电压控制的衰减器被用作音频限制器的关键元件。