公开(公告)号：US06720828B2

公开(公告)日：2004-04-13

申请号：US09992058

申请日：2001-11-21

申请人： Theodore G. Nelson ,  Michael P. Khaw ,  Daniel G. Knierim ,  John F. Stoops

发明人： Theodore G. Nelson ,  Michael P. Khaw ,  Daniel G. Knierim ,  John F. Stoops

IPC分类号： H03G320

CPC分类号： H03H11/24

摘要： A high impedance attenuator for use in a test and measurement instrument employs compensation to adjust the low frequency attenuation to match the high frequency attenuation exhibited by the attenuator, rather than attempting to adjust the high frequency attenuation exhibited by the attenuator. In an alternate embodiment of the invention, compensation to adjust low frequency attenuation is employed in a feedback loop and an opposite compensation is applied in a parallel attenuation stage to stabilize the input resistance. In yet another embodiment of the invention, compensation to adjust low frequency attenuation is employed by means of an R-C time constant of an additional R-C circuit in a feed forward loop. This additional time constant is matched to the R-C time constant of the input R-C network. The input resistance of the attenuator is not changed.

摘要翻译： 用于测试和测量仪器的高阻抗衰减器采用补偿来调节低频衰减，使其与衰减器所显示的高频衰减相匹配，而不是试图调整衰减器所表现的高频衰减。 在本发明的替代实施例中，在反馈环路中采用用于调节低频衰减的补偿，并且在并联衰减级中施加相反的补偿以稳定输入电阻。 在本发明的另一个实施例中，通过前馈环路中附加的R-C电路的R-C时间常数来采用用于调整低频衰减的补偿。 这个额外的时间常数与输入R-C网络的R-C时间常数相匹配。 衰减器的输入电阻不变。

公开(公告)号：US07525346B2

公开(公告)日：2009-04-28

申请号：US10193834

申请日：2002-07-11

申请人： Michael P. Khaw ,  Daniel S. Draper

发明人： Michael P. Khaw ,  Daniel S. Draper

IPC分类号： H03F3/45

CPC分类号： H03F3/45089 ,  H03F2203/45344 ,  H03F2203/45352 ,  H03F2203/45394 ,  H03F2203/45566 ,  H03F2203/45612 ,  H03F2203/45702

摘要： In one system embodiment, the system is characterized by: a differential amplifier including but not limited to at least one amplifying transistor having an emitter coupled directly to a ground. In one embodiment of a method of making a system, the method is characterized by: operably coupling at least one amplifying transistor of a differential amplifier directly to a ground. In one embodiment of a method of driving a system, the method is characterized by: driving at least one amplifying transistor of a differential amplifier with an emitter-follower feedback loop. In one system embodiment, the system is characterized by: a differential amplifier including but not limited to a first amplifying transistor having a base operably coupled with a first emitter-follower feedback loop.

摘要翻译： 在一个系统实施例中，该系统的特征在于：差分放大器，包括但不限于至少一个放大晶体管，其具有直接耦合到地的发射极。 在制造系统的方法的一个实施例中，该方法的特征在于：可操作地将差分放大器的至少一个放大晶体管直接耦合到地。 在驱动系统的方法的一个实施例中，该方法的特征在于：利用射极跟随器反馈回路驱动差分放大器的至少一个放大晶体管。 在一个系统实施例中，该系统的特征在于：差分放大器，包括但不限于第一放大晶体管，其具有与第一发射极 - 跟随器反馈回路可操作耦合的基极。

公开(公告)号：US5517154A

公开(公告)日：1996-05-14

申请号：US372545

申请日：1995-01-13

申请人： Clifford E. Baker ,  Michael P. Khaw

发明人： Clifford E. Baker ,  Michael P. Khaw

IPC分类号： G01R13/22 ,  G01R1/30 ,  G01R15/24 ,  G01R19/00 ,  H03F1/42 ,  H03F3/38 ,  H03F3/68 ,  H03H11/02 ,  G01R13/20 ,  H03F17/00

CPC分类号： H03F3/38 ,  G01R15/24 ,  H03F2200/273 ,  H03F2200/276 ,  H03F2200/39

摘要： A split-path isolation amplifier (10) employs a transformer (30) in a high path (26) and a single-input, dual-output closed-loop optocoupler (66) in a low path (24) to achieve a flat, wide frequency response without need for frequency compensation adjustments. In a low path frequency region (106), the optocoupler provides all or most of the signal to the output. The isolation amplifier employs a substantially overlapped crossover frequency region (104) in which the high path signal is applied to a primary winding (28) of the transformer, and the low path signal is applied differentially to secondary windings (40, 42) of the transformer. At frequencies below the crossover frequency range, the signal from the optocoupler dominates as the signal coupled from the primary winding rolls off. At frequencies above the crossover frequency range, the signal coupled from the primary winding dominates as the signal from the optocoupler rolls off. At frequencies within the crossover frequency range magnetic flux components generated by the primary and secondary transformer windings co-act to provide a combined output signal having a flat frequency response. The only adjustments are those required to match the gain of the low path to the gain of the high path and to compensate for any offset in the low path.

摘要翻译： 分路隔离放大器（10）在高路径（26）中使用变压器（30）和在低路径（24）中的单输入双输出闭环光耦合器（66），以实现平坦， 宽频率响应，无需频率补偿调整。 在低路径频率区域（106）中，光耦合器向输出端提供全部或大部分信号。 隔离放大器使用基本上重叠的交越频率区域（104），其中高路径信号被施加到变压器的初级绕组（28），并且低路径信号被差分地施加到第二绕组（40,42） 变压器。 在低于交叉频率范围的频率下，从初级绕组耦合的信号滚降时，来自光耦合器的信号占主导地位。 在高于交叉频率范围的频率下，从初级绕组耦合的信号由光耦合器的信号消失。 在交叉频率范围内的频率，由主变压器绕组和次级变压器绕组产生的磁通量分量协同提供具有平坦频率响应的组合输出信号。 唯一的调整是将低路径的增益与高路径的增益相匹配的调整，并补偿低路径中的任何偏移量。