公开(公告)号：WO9950958A3

公开(公告)日：2000-01-06

申请号：PCT/IB9900429

申请日：1999-03-15

Applicant: PLASMON LMS INC

Inventor： HEMDAL HAKAN O ,  BROOKE JEFFREY M

IPC: H03H11/12

CPC classification number: H03H11/1291

Abstract: A switchable active filter circuit is formed which employs a ground based switch to direct a portion of a feedback current away from a virtual ground terminal of an operational amplifier, thereby providing enhanced circuit Q and greater phase control at frequencies approaching an octave from the unity gain crossover frequency of an operational amplifier used to form the filter. The circuit employs a switchable feedback tee which includes a first capacitor, a second capacitor, a third capacitor and a switch. The first capacitor and the second capacitor form a first series circuit which is connected from the output terminal to the input terminal of the operational amplifier. The third capacitor and the first switch are connected as a second series circuit which is coupled from circuit ground potential to a junction of the first capacitor and the second capacitor. When the switch is closed, a feedback current flowing in the feedback tee is divided with a portion of the current flowing through the third capacitor to circuit ground, rather than into the virtual ground terminal of the operational amplifier. This filter topology is particularly well suited for use in a multi-mode read/write channel of a tape storage system.

Abstract translation: 形成了可切换的有源滤波器电路，其采用基于地的开关来将反馈电流的一部分引导到运算放大器的虚拟接地端子，从而在从单位增益接近八度的频率处提供增强的电路Q和更大的相位控制 用于形成滤波器的运算放大器的交越频率。 电路采用可切换的反馈三通，其包括第一电容器，第二电容器，第三电容器和开关。 第一电容器和第二电容器形成从输出端子连接到运算放大器的输入端的第一串联电路。 第三电容器和第一开关作为从电路接地电位耦合到第一电容器和第二电容器的结的第二串联电路连接。 当开关闭合时，在反馈三通中流动的反馈电流与流过第三电容器的电流的一部分被分配到电路接地，而不是进入运算放大器的虚拟接地端。 该滤波器拓扑特别适用于磁带存储系统的多模式读/写通道。

公开(公告)号：WO98035438A2

公开(公告)日：1998-08-13

申请号：PCT/IB1998/000048

申请日：1998-01-15

IPC: H03F1/32 ,  H03F1/34 ,  H03H11/02 ,  H03H11/04 ,  H03H11/12

CPC classification number: H03H11/04

Abstract: A tunable balanced RC filter circuit of the type in which the resistors are formed as MOS transistors with variable gate voltages for tuning the filter. The MOS transistor takes the form of a series arrangement of individual MOS transistors (T1-1, T1-2, ..., T1-N; T2-1, T2-2, ..., T2-N) each having the same d.c. bias on its gate. The gate of each of the individual MOS transistors in the series arrangement also receives a fraction of the a.c. component of the input signal on the input terminals (IT1, IT2) of the two-port network by means of a resistor ladder (R1-1, R1-2, ..., R1-N, R2-1, R2-2, ..., R2-N), which is connected to the input terminals (IT1, IT2) via buffers (B1, B2). The a.c. component of the input signal is thus divided among the individual transistors in the series arrangement. In this way it is possible to use MOS transistors with a small gate voltage swing at comparatively large input voltages.

Abstract translation: 一种可调平衡RC滤波器电路，其中电阻器形成为具有可变栅极电压的MOS晶体管，用于调谐滤波器。 MOS晶体管采取单独的MOS晶体管（T1-1，T1-2，...，T1-N; T2-1，T2-2，...，T2-N）的串联布置的形式， 相同的直流 偏向门。 串联装置中的每个单独的MOS晶体管的栅极也接收一部分交流电。 通过电阻梯（R1-1，R1-2，...，R1-N，R2-1，R2-2）在双端口网络的输入端（IT1，IT2）上输入信号的分量 ，...，R2-N），其经由缓冲器（B1，B2）连接到输入端子（IT1，IT2）。 a.c. 输入信号的分量因此在串联装置中的各个晶体管之间分配。 以这种方式，可以在较大的输入电压下使用具有较小栅极电压摆幅的MOS晶体管。

公开(公告)号：WO1997032396A1

公开(公告)日：1997-09-04

申请号：PCT/JP1997000577

申请日：1997-02-26

Applicant: MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD. ,  MORITA, Yoichi

Inventor： MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD.

IPC: H03H11/12

CPC classification number: H03H11/46

Abstract: A frequency-dependent resistor comprising phase rotating devices each of which rotates the phase of the input voltage by 90 DEG and is constituted by connecting a reactance load represented by a coil or capacitor to the output of a voltage-current converter. The phase rotating devices are cascade-connected to each other. The voltages outputted from even-numbered phase rotating devices are converted to currents and fed to the input terminals of the first stage.

Abstract translation: 一种频率相关电阻器，包括相位旋转装置，每个相位旋转装置将输入电压的相位旋转90°，并且通过将由线圈或电容器表示的电抗负载连接到电压 - 电流转换器的输出而构成。 相位旋转装置彼此级联连接。 从偶数相位旋转装置输出的电压转换为电流，并馈送到第一级的输入端。

公开(公告)号：WO1997004524A1

公开(公告)日：1997-02-06

申请号：PCT/US1996011517

申请日：1996-07-10

Applicant: THE BOEING COMPANY

Inventor： THE BOEING COMPANY ,  MAXWELL, Scott, D.

IPC: H03H11/12

CPC classification number: H03H11/1291

Abstract: A voltage controlled filter circuit with a voltage controlled resistor as a control element having a D.C. voltage applied to an ADC (analog to digital converter) compared to a supplied reference voltage, and as bits are set to HIGH or LOW level, then N Channel enhancement mode MOSFETs are turned on or off, bypassing the resistors in the ON state and placing the resistor in the current path when in the OFF state, providing control of the filter cutoff or critical frequency, critical frequency range being user selectable with external capacitor(s).

Abstract translation: 具有作为控制元件的压控电阻器的电压控制滤波器电路，与提供的参考电压相比具有施加到ADC（模数转换器）的DC电压，并且将位设置为高电平或低电平，然后N沟道增强 模式MOSFET导通或关断，旁路电阻处于导通状态，并将电阻置于电流路径中，处于关闭状态，提供滤波器截止或临界频率的控制，临界频率范围可由用户选择外部电容 ）。

公开(公告)号：WO1996036112A1

公开(公告)日：1996-11-14

申请号：PCT/GB1996001131

申请日：1996-05-13

Applicant: AMSTRAD PLC ,  GREENFIELD, Raymond

Inventor： AMSTRAD PLC

IPC: H03H11/12

CPC classification number: H04N1/00281 ,  H03H11/1217 ,  H04M19/08

Abstract: An isolating circuit for isolating a telephone set from an exchange passes a D.C. feed current but prevents A.C. currents over the range of operating frequencies of the equipment, typically about 300 Hz to 4 KHz. The circuit comprises a T-filter having two resistive branches arranged between the source and the load, and a capacitive branch arranged between the resistive branches and earth. The resistive branches each include a resistive element having an amplifier (A1, A2) in parallel with a resistor (R1, R4). The effective resistance of the resistive branches is dependent on the gain of the amplifier, which is isolated from D.C. by capacitors (C1, C2, C3, C4). The impedance of the capacitive branch is chosen so as to be lower than that of the resistive branches over the frequency range of interest thus isolating the two resistive branches from one another at those frequencies.

Abstract translation: 用于将电话机与交换机隔离的隔离电路通过直流供电电流，但防止在设备的工作频率范围内的通常为约300Hz至4KHz的交流电流。 电路包括具有布置在源极和负载之间的两个电阻分支的T滤波器，以及布置在电阻分支和地之间的电容分支。 电阻分支各自包括具有与电阻器（R1，R4）并联的放大器（A1，A2）的电阻元件。 电阻分支的有效电阻取决于放大器的增益，放大器通过电容器（C1，C2，C3，C4）与直流电隔离。 电容分支的阻抗被选择为低于感兴趣的频率范围上的电阻分支的阻抗，因此在这些频率处将两个电阻分支彼此隔离开。

公开(公告)号：WO2022153926A1

公开(公告)日：2022-07-21

申请号：PCT/JP2022/000307

申请日：2022-01-07

Applicant: 株式会社村田製作所

Inventor： 森　弘嗣 ,  帯屋　秀典 ,  佐野　智弘

IPC: H04B1/52 ,  H03H11/12 ,  H04B1/00 ,  H04B1/48

Abstract: 高周波回路（１）は、アンテナ接続端子（１００）に接続され、第１バンドを含む通過帯域を有するフィルタ（３０）と、アンテナ接続端子（１００）に接続され、第１バンドと同時伝送可能な第２バンドを含む通過帯域を有するフィルタ（４０）と、フィルタ（３０）に接続されたアクティブ回路（１０）と、を備え、アクティブ回路（１０）は、低雑音増幅器（１１）と、低雑音増幅器（１１）の帰還経路に配置された第１キャパシタと、帰還経路に配置された第１インダクタおよび第１抵抗の少なくとも一方と、を有する。

公开(公告)号：WO2020030533A1

公开(公告)日：2020-02-13

申请号：PCT/EP2019/070841

申请日：2019-08-01

Applicant: IMPERIAL COLLEGE OF SCIENCE, TECHNOLOGY AND MEDICINE

Inventor： DRAKAKIS, Emmanuel M ,  PETKOS, Konstantinos ,  ZAFEIROPOULOS, Georgios

IPC: H03H11/12

Abstract: Provided is a tunable electronic filter comprising: an input stage (304) coupled to a tuning stage; an amplifier (302) with a non-inverting input coupled to an output of the tuning stage, and an inverting input coupled to ground, and an output (303); and an output stage coupled to the amplifier output; wherein the tuning stage comprises N RC networks (301) and a multiplexer (305), wherein the N RC networks are connected in parallel between the input stage and respective inputs of the multiplexer; wherein the multiplexer is configured to selectively connect one of the N RC networks to the non-inverting input of the amplifier, such that a second order Sallen-Key filter is formed between the input stage and the output stage, wherein selection of one of the N RC networks tunes the electronic filter to have a respective one of N frequency responses, for N ≥2.

公开(公告)号：WO2019074714A1

公开(公告)日：2019-04-18

申请号：PCT/US2018/053882

申请日：2018-10-02

Applicant: QUALCOMM INCORPORATED

Inventor： GATHMAN, Timothy Donald ,  PATEL, Chirag Dipak ,  LEUNG, Lai Kan ,  YU, Xinmin ,  RANGARAJAN, Rajagopalan

IPC: H04B1/10 ,  H03H11/12

Abstract: In certain aspects, a circuit comprises a low noise amplifier (LNA) configured to receive a radio frequency (RF) signal, a first mixer coupled to the low noise amplifier (LNA), and a first trans-impedance filter coupled to the first mixer. The first transimpedance filter comprises a tunable inductor and capacitor (LC) network configured to be a portion of a doubly terminated LC ladder filter and a trans-impedance amplifier (TIA) coupled to the tunable inductor and capacitor (LC) network. The circuit further comprises a second mixer coupled to the low noise amplifier (LNA) and a second trans-impedance filter coupled to the second mixer.

公开(公告)号：WO2018215973A1

公开(公告)日：2018-11-29

申请号：PCT/IB2018/053705

申请日：2018-05-24

Applicant: NIELSEN, Jorgen ,  NICHOLS, Richard

Inventor： NIELSEN, Jorgen ,  NICHOLS, Richard

IPC: H03H9/54 ,  H03H9/64 ,  H03H11/12

Abstract: A method and apparatus for modifying or controlling a resonator connected to a signal loop having an input (18828), an output (18822), and a closed loop frequency response. The signal loop has a primary resonator (18810) having a primary frequency response. There is at least one adjustable resonator (18812) having an adjustable frequency (f) and a secondary Q-factor. An adjustable scaling block (18824) applies a gain factor (g). A controller is connected to the at least one adjustable resonator (18812) and the adjustable scaling block (18824). The controller has instructions to adjust the closed loop frequency response toward a desired closed loop frequency response by controlling the adjustable frequency (f) of the at least one adjustable resonator (18812) and the gain factor (g) of the adjustable scaling block (18824).

公开(公告)号：WO2018050221A1

公开(公告)日：2018-03-22

申请号：PCT/EP2016/071688

申请日：2016-09-14

Applicant: HUAWEI TECHNOLOGIES CO., LTD. ,  GRAMEGNA, Giuseppe

Inventor： GRAMEGNA, Giuseppe

IPC: H03H11/12

Abstract: A filter circuit (70), comprising a filter (72) and a current mode programmable gain amplifier (74), is provided. The filter circuit (70) is configured to filter an input signal (VF_IN+, VF_IN-, ), resulting in an output signal. The filter (72) is supplied with the input signal (VF_IN+, VF_IN-, ). The filter (72) comprises at least one current extraction element (73), configured to extract a first output current signal. The current mode programmable gain amplifier (74) is configured for receiving and amplifying the first output current signal resulting in an amplified current signal, the output signal is derived from.

Abstract translation: 提供了包括滤波器（72）和电流模式可编程增益放大器（74）的滤波器电路（70）。 滤波器电路（70）被配置为对输入信号（VF_IN +，VF_IN-）进行滤波，从而产生输出信号。 滤波器（72）提供有输入信号（VF_IN +，VF_IN-，）。 滤波器（72）包括至少一个电流提取元件（73），其被配置为提取第一输出电流信号。 电流模式可编程增益放大器（74）被配置用于接收并放大第一输出电流信号，从而产生放大的电流信号，输出信号来源于。