An operational amplifier which comprises a first amplifying circuit; a second amplifying circuit which is connected to the first amplifying circuit and carries out inverting amplification; a third amplifying circuit which is connected to the second amplifying circuit, carries out noninverting amplification and has a gain of substantially 1; a first feedback circuit which is connected between the output and input terminals of the second amplifying circuit and carries out phase-compensation; and a second feedback circuit which is connected between the output terminal of the third amplifying circuit and the input terminal of the second amplifying circuit, and carries out phase-compensation.
An operational amplifier is provided with an improved frequency compensation circuit, wherein a first compensation circuit inserts a first dominant pole at a first predetermined frequency for decreasing the magnitude of the ouput signal of the operational amplifier with increasing frequency, while a second compensation circuit inserts a pole and a zero at second and third predetermined higher frequencies in the transfer function of the operational amplifier, respectively, for stabilizing the first compensation circuit and ensuring the stability of the operational amplifier over the operational bandwidth. The pole and zero of the second compensation circuit inserts a positive phase shift about the third predetermined frequency effectively extending the phase response of the operational amplifier and allowing the frequency of the first dominant pole to be increased without sacrificing phase and gain margin. The higher frequency of the dominate pole provided by the first compensation circuit increases the gain-bandwidth product of the operational amplifier thereby improving its overall performance.
A signal deciding apparatus which can obtain a stable digital signal OUT irrespective of an amplitude and a duty ratio of an input signal IN is provided. The input signal IN is amplified by inverters (5.sub.1 to 5.sub.3 and 8) and outputted as a digital signal OUT. A signal (S5) on the input side of the inverter (8) is integrated by a time constant which is equal to a data period of the input signal IN by an integrator (9) and supplied to a differential amplifier (20). A signal (S8) on the output side of the inverter (8) is integrated by a large time constant by an integrator (10), a control voltage VC supplied from a control terminal (13) is multiplexed to the integrated signal S8, and a resultant signal is sent to the differential amplifier (20). An output signal of the differential amplifier (20) is integrated by a resistor (11) and a capacitor (4) and its average level is fed back as a threshold voltage to the input side of the inverter (5.sub.1) through a resistor (3) and multiplexed to the input signal IN. Thus, the digital signal OUT based on the duty ratio of the input signal IN is obtained.
An input stage for a low-noise broadband amplifier includes a negative feedback capacitor connected between an input and an output of at least one amplifier element. The output of the amplifier element is terminated with a capacitor. The input stage has a real, constant input impedance in a broad range.
A bi-directional signal transmission system comprises a bi-directional signal path with a low-impedance section coupled to a high-impedance section through a signal coupling for transmission of a binary signal in both directions; and adapting means for adapting the signal coupling under control of the signal itself, dependent on the transmission direction. I.sup.2 C-bus systems in particular benefit from the presence of the adapting means since communicating stations now can be located farther apart than was practical previously. In addition, the driving capability of the transmitting station is no longer a limiting factor.
4897617 - Domino effect amplifier - Owned by The United States of America as represented by the Secretary of the Air (Washington, DC)
This high voltage linear FET amplifier operates at voltage levels of ten's of thousand's of volts with power dissipation capabilities in the kilowatt range. It is a broadband device which features power amplification from DC to frequencies well in excess of 100 KHz. The amplifier uses a unity-gain inverting amplifier as its basic building block. N-number of these building blocks are stacked to accommodate whatever voltage stand-off level is desired. To operate stacked high voltage amplifiers, it is necessary to provide a bias shift (reference) progressively increasing in equal increments from the ground reference stage to the highest voltage level stage while preserving the fidelity of the signal applied to the first stage. This is done by establishing a phantom ground at all amplifiers for each progressive bias level.
