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Class 330/75 - SIGNAL FEEDBACK


Subclass of Class 330 - Amplifiers
Definition: Subject matter wherein signal feedback circuit means are
No. of patents: 44
Last issue date: 09/09/2008


1    
NumberTitleIssue Date
7423480AC amplifier for precision measurement
A front-end circuit suitable for digital multimeters and measurement devices may be configured with strictly capacitive attenuators replacing the resistive attenuators in the AC signal path. An inverting programmable-gain amplifier (PGA) may be built around an opera...
09/09/2008
7395038High-efficiency modulating RF amplifier
The present invention, generally speaking, provides for high-efficiency power control of a high-efficiency (e.g., hard-limiting or switch-mode) power amplifier in such a manner as to achieve a desired modulation. In one embodiment, the spread between a maximum frequ...
07/01/2008
7339436Ultra broad-band low noise amplifier utilizing dual feedback technique
This invention relates to a low noise amplifier, used in radio frequency integrated circuit design, especially low noise amplifiers for ultra broad-band wireless communication, comprising at least a transistor of the core circuit of a low noise amplifier structure, ...
03/04/2008
7279970Feedback circuit
For reducing various adverse effects due to provision of a low-pass filter, while suppressing an oscillation generated therein, there is provide a feedback circuit, having at least one operational amplifier, having a low-pass filter in an output portion thereof, for...
10/09/2007
7221226Amplifying apparatus with automatic level controller
A window comparator compares a level of an output signal with an attack reference level, and outputs an attack signal based upon an attack reference comparison result signal thus obtained, and compares the output signal level with a recovery reference level, and out...
05/22/2007
7212627Line interface with analog echo cancellation
A line interface performs echo cancellation without the use of a hybrid filter network and includes a transmit path having a line driver, a single matching network terminating the line, and a single transformer. The transformer uses split windings on both the primar...
05/01/2007
7164893Method and apparatus for optimizing supply modulation in a transmitter
A transmitter (200) has a compression detector for sensing the level of compression (110) in a signal that is being transmitted. The transmitter also has a radio frequency power amplifier (RFPA) (414) that is supplied by a supply modulator (4...
01/16/2007
7161419Sensor device and a signal amplification device of a small detection signal provided by the sensor
An amplification device for a small detection signal has an amplification factor that is variable and also high accuracy offset cancellation. A first switching element selectively connects a normal phase input terminal of an operational amplifier either to a referen...
01/09/2007
7113037Performing remote power amplifier linearization
Estimating non-linearity of a power amplifier includes receiving signals at a first location. The signals include an input signal, a pre-distorted signal, and an output signal. The output signal exhibits distortion, including a non-linearity effect, with respect to ...
09/26/2006
7106104Integrated line driver
The present invention provides integrated line drivers useable for driving data signals with high data rates wherein the area consumption of the line driver is minimized and wherein the influence of electrostatic discharge devices and process tolerances are minimize...
09/12/2006
7102430Efficient method and means for integration of power control and predistortion in a transmitter
A radio-frequency (RF) transmitter power amplifier circuit provides for practically linear performance by predistorting the amplifier input signals to compensate for amplifier distortion at high power levels, and provides a fine degree of control of amplifier power ...
09/05/2006
7099635High-efficiency modulating RF amplifier
The present invention, generally speaking, provides for high-efficiency power control of a high-efficiency (e.g., hard-limiting or switch-mode) power amplifier in such a manner as to achieve a desired modulation. In one embodiment, the spread between a maximum frequ...
08/29/2006
7088176Method and arrangement relating to multicarrier power amplifiers
The present invention relates to a Multi Carrier Power Amplifier, MPCA, comprising a number of parallel Multi Carrier Power Amplifiers, each comprising an amplification loop and an error cancellation loop, said amplification loop comprising at least a first gain and...
08/08/2006
7068098Slew rate enhancement circuit
An operational amplifier (op-amp) (200, 800, 900) having at least a first stage and a second stage has a feedback path (825) from the output to the input of a second stage, the feedback path includes a first capacitor (801) and a second capacito...
06/27/2006
7065143Method and design for increasing signal to noise ratio in xDSL modems
A DSL modem comprises an additional transformer and additional coils on a coupling transformer to couple a received signal on a transmission line to a receive path without loss due to an active impedance. The ratio of windings on the coils allows gain to be introduc...
06/20/2006
7058540Method and system for accelerating power complementary cumulative distribution function measurements
Data values representing the (I2+Q2) values are converted to floating-point representations and a histogram of the floating-point numbers is generated. The count for each histogram bin in the histogram is stored in a memory. Each floating-point...
06/06/2006
7009438Trans-admittance trans-impedance logic for integrated circuits
A logic circuit with improved performance when operating at the limits of the transistor's bandwidth. In particular, a latch includes a clocked trans-admittance stage circuit for receiving a voltage and producing a current output, and an active load, such as a trans...
03/07/2006
6985033Circuits and methods for adjusting power amplifier predistortion, and power amplifiers and other devices including the same
An amplifier with adjustable (pre)distortion, a predistortion adjustment circuit, systems and networks including such amplifiers and circuits, and methods for adjusting (pre)distortion in an analog amplifier. The amplifier architecture generally includes (a) a predi...
01/10/2006
6930548Method and system for improving amplifier efficiency
One aspect of the invention is an amplifier (10), comprising an input stage amplifier (20) coupled to an output node (81). The amplifier (10) further comprises a class D output stage (50), which comprises at least two switching ele...
08/16/2005
6920336Broadband driver
Broadband driver for signals that are transmitted in different frequency ranges, comprising: (a) a first broadband driver circuit (19) for driving first signals having signal frequencies that lie in a first frequency range; (b) a sec...
07/19/2005
6879216Integrated circuit that provides access to an output node of a filter having an adjustable bandwidth
An IC includes an externally accessible terminal, a filter, and an output stage. The filter has an adjustable bandwidth and has an output node coupled to the externally accessible terminal, and the output stage has an input node coupled to the output node of the fil...
04/12/2005
6847807Transmission circuit and radio transmission apparatus
A modulator receives an I-phase transmission data signal and a Q-phase transmission data signal, which have been spread-spectrum processed, and modulates an intermediate frequency signal in accordance with the data signals, an IF-AGC amplifier amplifies the output o...
01/25/2005
6833757Method and system for improving amplifier efficiency
One aspect of the invention is an amplifier (10), comprising an input stage amplifier (20) coupled to an output node (81). The amplifier (10) further comprises a class D output stage (50), which comprises at least two switching ele...
12/21/2004
6766153Dynamic automatic gain control circuit employing kalman filtering
A novel and useful apparatus for and method of automatic gain control (AGC) using Kalman filtering and hysteresis. A nonlinear, time-variant loop filter such as a Kalman filter is employed in the feedback loop of an AGC circuit. The circuit is able to transition qui...
07/20/2004
6647073Linearisation and modulation device
The present invention discloses a linearisation and modulation device for a power amplifier. The linearisation and modulation device comprises a digital vector modulator (103, 104, 105) for generating a modulated digital signal (IF_MOD) on the basis of di...
11/11/2003
6566947Combined active impedance and filter in line drivers
A line driver combining active impedance and filter in one stage for connection to a transmission line having a characteristic impedance. The line driver comprises an amplifier, a transformer with a primary to secondary winding ratio of 1:n, a reference i...
05/20/2003
6407631Charge-type sensor amplifying circuit
A charge-type sensor amplifying circuit includes an operational amplifier having an inverting input terminal thereof connected to one terminal of a charge-type sensor, a voltage divider having two voltage-dividing points which divide the output voltage fr...
06/18/2002
6023363Optical transmission apparatus
An optical transmission apparatus includes a feedback amplification circuit having flat and wideband frequency characteristics in which the linearity within a band is excellent. As a result, frequency characteristics of the optical transmission apparatus ...
02/08/2000
6005316Current mode switching for tri-state amplifiers in magnetic bearing control systems
A method of controlling switching of a tri-state switching amplifier having two switching legs, two switches in each leg, and a load connected to the junction between the switches of each leg, a power supply and a capacitor connected to the opposite ends ...
12/21/1999
5977824Circuit feedback loop with monitored loop gain
A circuit arrangement includes a feedback loop, with a forward path and a feedback path, and a re-combining stage. A measuring circuit is provided to produce a measuring signal derived from a result signal and a feedback signal by linear combination....
11/02/1999
5515001Current-measuring operational amplifier circuits
An operational amplifier connected in series with a load and a current-measuring impedance and having at least two input ports and an output port, the output port of the operational amplifier further being directly connected to current-measuring impedance...
05/07/1996
5347529Method for generating a distortion-free, frequency-modulated optical signal and apparatus for the implementation of such a method
Method and apparatus for generating a distortion-free, frequency-modulated optical signal, whereby this signal from an optical semiconductor laser driven with a modulating voltage is distorted by the modulating voltage due to a thermally conditioned frequ...
09/13/1994
5327095Method and circuit for increasing the output impedance of an inactive amplifier
A method and circuit for increasing the output impedance of an inactive amplifier is provided. The method and circuit allows an increased number of amplifiers to be coupled in parallel to a single transmission line for distributing a plurality of video or...
07/05/1994
4644138Temperature control system with simplified controller and power supply
The invention includes a simple and inexpensive thermal controller and simple and inexpensive radio frequency alternating current generator which are provided in an improved temperature control system for a resistively heated electrochemical cell. The tem...
02/17/1987
4618814Voltage-to-current converter circuit
A voltage-to-current converter circuit for outputting a current accurately proportional to the input signal voltage, which converter circuit includes an operational amplifier for providing an output corresponding to a difference between the input signal a...
10/21/1986
4580104High voltage operational amplifier
A d.c. high voltage operational amplifier. The output of a conventional power operational amplifier is converted to a.c. which is stepped up by a transformer and then rectified to provide a high voltage d.c. output. Appropriate feedback circuitry is utili...
04/01/1986
4409556Amplifier arrangement with very low distortion
A low distortion amplifier arrangement includes an amplifier having an inverting input, a non-inverting input, and an output, a first impedance coupled between the output and the inverting input, and a second impedance coupled between an input terminal of...
10/11/1983
4383222Half-wave signal isolator with compensator means to reduce temperature-dependent effects
A signal isolator including a coupling transformer with modulate/demodulate switches in series with the primary and secondary windings. The switches are driven in synchronism by an oscillator. Resonating capacitors are connected in parallel with the trans...
05/10/1983
4360784Transformer coupled isolation amplifier
A transformer-coupled isolation amplifier which has a minimally sized transformer, high common mode rejection, and a highly linear response over a wide dynamic range. A first chopper periodically alternates by 180° the connection of the input through a h...
11/23/1982
4191929Isolation amplifier with high linearity
A transformer-coupled isolation amplifier which can accept signals over a wide dynamic range while maintaining very high linearity. An input signal is applied to an input winding of a transformer. The secondary winding of the isolation transformer is conn...
03/04/1980
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