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7610022 Filter circuit with negative transconductance  
Apparatus, systems, and methods implementing techniques for filtering signals are described. A filter circuit receives an input signal and produces a corresponding filtered signal. The filter...
7525372 Noise shaped n th order filter  
A low noise nth order filter, system, and method includes a plurality of nested general immittance converters (GICs) operatively connected to one another in successive GIC stages; and a capacitor...
7511570 Transconductance filtering circuit  
A transconductance filtering device with a flexible architecture that can selectively present a different topology and/or order beginning with the same initial structure is disclosed. For example,...
7495508 Switched capacitor notch filter circuits  
Switched capacitor notch filter circuits are disclosed. An example switched capacitor notch filter circuit described herein includes a switched capacitor amplifier to receive an input signal and a...
7429889 Control system for programmable filters  
Control system for programmable filters, master-slave calibration system and fully programmable high precision filter for use in such control system, such filters being provided with a filter input...
7323955 Narrow-band absorptive bandstop filter with multiple signal paths  
An absorptive bandstop filter includes at least two frequency-dependent networks, one of which constitutes a bandpass filter, that form at least two forward signal paths between an input port and...
7268615 Trap filter  
A trap filter comprises a delay circuit made up of switched capacitors for delaying an input signal and outputting a delay signal, and an adding circuit for adding the input signal and the delay...
7127226 Twin-T dual notch filter  
A communication filter circuit useful in a dual-mode receiver comprises a cascade of an active twin-T filter and a passive twin-T filter sections defining sharp notches at the center of second...
7109786 Biquad notch filter  
A biquad notch filter includes a first stage having first and second admittances of a first type connected between an input terminal and the control terminal of a transistor, a first current source...
7002417 RC and SC filter compensation in a radio transceiver  
Disclosed is apparatus for operating with an RC filter ( 26, 26 A), and a corresponding method. The apparatus includes circuitry ( 32 ) for use in measuring an actual value of at least one filter...
6930544 Filter  
The object of the present invention is to obtain a high precision notch filter or all-pass filter. Therefore, two transconductance circuits for adjustment, which perform a voltage-current...
6909321 Active isolated-integrator low-pass filter with attenuation poles  
The present invention provides an active low-pass filter system including a low-pass filter circuit and at least one frequency-rejecting network coupled to the low-pass filter circuit. The...
6867642 Realtime adaptive notch compensator  
A notch compensation apparatus and method comprising, based on input to and output from a notch filter, dynamically calculating a desired change to a notch frequency of the notch filter and...
6803812 Active filter  
A low pass notch filter has a notch frequency close to ω o . In the notch filter, an output of an operational amplifier is fed back to an inverting input terminal thereof through a second voltage...
6791401 Continuous-time analog filter having controllable gain characteristics  
A Gm-C filter includes a filter passing an intended signal SI# in an input signal SI, and a control signal producing portion detecting a peak voltage value of an output signal of a filter to be...
6677815 Second order active RC filter with imaginary zero  
A stop band second order active RC filter architecture that does not use a non-inverting input to receive an input signal, and that employs both positive and negative feedback to provide an RC...
6608898 Band pass and notch filters for echo reduction with less phase distortion  
A complementary comb filter includes a plurality of band pass filters and a plurality of notch filters, wherein the notch filters have the same center frequencies as the band pass filters or the...
6552604 Digitally tuned analog notch filter circuit  
A notch filter circuit is provided including a first stage circuit and a second stage circuit. The first stage circuit sums a filter input signal with a filter output signal to form a summation...
6507239 Low noise and low offset bipolar input amplifiers  
The present invention comprises an input amplifier circuit that provides a low input offset voltage amplified output signal. Input amplifiers of the present invention include a differential pair of...
6404279 Band pass filter with improved group delay  
An electrical signal is applied to a band pass filter, a first notch filter, and a second notch filter in any order. The center frequencies of the notch filters straddle the pass band of the band...
6373332 Biquad notch filter  
When using an operational amplifier having a small gain-band width product, in order to obtain a circuit having deep notch characteristics, a biquad filter includes first and second stages having...
6320459 Notch filter implemented using analog sampling  
A filter system includes a low pass filter, a first summer circuit, a second low pass filter and a second summer circuit. The first low pass filter includes an input, an output, a storage means, a...
6271720 Operational filter building block  
A 3-terminal operational filter circuit is presented that can be used to construct various types of active filters. The filter circuit can be used to construct various orders of low pass,...
6268766 Band pass filter from two notch filters  
A band pass filter includes a pair of notch filters having different notch frequencies and a difference amplifier coupled to the outputs of the notch filters. The notch filters preferably have...
6157248 Active filter circuit  
An active filter circuit (a band stop filter type or a band pass filter type) having high Q value and high efficiency and which is suitable for integration has an input signal vi inputted from the...
6097244 Highly-linear continuous-time filter for a 3-volt supply with PLL-controlled resistor and digitally-controlled capacitor  
A continuous-time filter is highly linear even when used with reduced 3-volt power supplies. In each stage of a multi-stage ladder network, resistor networks are attached to each input of a...
6020783 RF notch filter having multiple notch and variable notch frequency characteristics  
A filter network having the capability of establishing multiple, tunable notch frequencies. A notch filter path is established for each notch frequency and includes a bandpass filter and inverter....
6002297 Digital filter  
In a bandpass filter, a first cyclical analogue signal V3 at a center frequency divided by integer N in divide 44 and the divided signal supplied to a digital filter 48 as its system clock; a...
5994952 Narrow band-pass interferometric filter having enhanced operational characteristics  
A narrow band-pass interferometric filter for applying a response characteristic to an input signal to produce a filtered output signal. The filter is comprised of an inverting amplifier having an...
5929700 Increased bandwidth for plants with resonant modes using nonlinear notch filters  
A control system includes a plant 56 having resonant modes and a controller 5 which receives plant input signals on lines 14,24 from the plant 56 and provides a controller output signal I, related...
5926063 Method of and apparatus for selectively engaging an internal trap filter and implementing an external trap filter through a single pin  
A method of and apparatus for selectively engaging an internal trap filter and implementing an external trap filter through a single pin routes a separate luminance signal through the pin or...
5751184 Low electrical power consumption filter circuit  
A low electric power consumption filter circuit includes an amplifying portion including an odd number of serial MOS inverters. A grounded capacitance is connected between an output of the...
5729170 Frequency divider  
An input buffer circuit for a frequency divider includes a bias circuit including a first group of diodes connected in series and to a power supply voltage terminal, at least first and second...
5694077 Reduced phase-shift nonlinear filters  
A reduced phase-shift nonlinear filter includes linear filter logic 10 responsive to a filter input signal x and having a linear transfer function G(s), which provides a linear filtered signal g,...
5451852 Control system having signal tracking window filters  
A control system having a source of control signals and a multi-window electrical signal tracking filter. The signal tracking filter includes an operational amplifier operating in the non-inverting...
5331299 Adaptive tracking notch filter system  
An automatic tracking notch filter system tracks a large-magnitude narrow band signal through frequency effectively eliminating it. A frequency variable notch filter is responsive to a control...
5331218 Switched-capacitor notch filter with programmable notch width and depth  
A notch filter circuit includes first and second operational amplifiers, each having a capacitor connected from the amplifier output to the input. A third capacitor is connected between the...
5298813 Polar leapfrog filter  
A polar leapfrog filter includes at least one polar network. The polar network comprises a differentiator constituted by an operational amplifier having input and output terminals, and a first...
5235223 Constant Q peaking filter utilizing synthetic inductor and simulated capacitor  
A tunable circuit is disclosed which allows tuning while maintaining a constant Q. The filter uses a synthetic inductor and a capacitance multiplier in place of discrete inductive and capacitive...
5053650 Monolithic semiconductor integrated circuit device having current adjusting circuit  
A monolithic semiconductor integrated circuit device includes a differentially operative circuit section, an amplifying element connected to define a current flowing in the differentially operative...
4939473 Tracking harmonic notch filter  
An electronic filter for automatically tracking and removing harmonically lated interfering electrical signals such as power line interference harmonics without attenuating other signals of...
4920563 Circuit compensating for the attenuation of a notch filter at frequencies less than cut-off frequency thereof  
A circuit compensating for the attenuation caused on a line by an LS series type notch filter at frequencies less than the filter cut-off frequency, with such filter connected across said line and...
4918337 Active RC filter having band-rejection and all-pass modes  
An active filter circuit operable in a band-rejection mode and in an all-pass mode. A cascade combination of an RC filter and amplifier circuit receives an input signal. A pair of amplifiers...
4841461 Filter adjustment apparatus and method  
A filter adjustment apparatus adjusts the properties of a filter by changing, for example, the circuit constants of a filter connected in series with a signal processing circuit to correspond with...
4804962 Clutter elimination radar  
A radar receiver having a clutter-elimination filter in the receiver's intermediate frequency stage. The filter is centered on the intermediate frequency f i and has a transfer function in which a...
4733403 Digital zero IF selectivity section  
Disclosed is a digital zero-IF selectivity section circuit which operates on a recovered input signal, digitally clocked by a first clock at a rate of FS, in receiver device. The circuit uses a...
4731587 Enhanced quadrature notch filter  
An enhanced quadrature notch filter which is capable of rejecting an undesired signal component of an input signal, generally comprising a quadrature phase splitter for producing first and second...
4679001 Adaptive stop-notch filter  
A filter suppresses energy at time varying or ensemble varying frequencies. The filter comprises multiplier sections having sets of values which are dynamically varied during the receipt of time...
4584580 Apparatus for rejecting jamming waves  
A variable-narrow-band rejection filter is inserted in a reception signal path for rejecting a jamming wave. Signals at input and output terminals of the narrow-band rejection filter are picked up...
4569072 Clock-controlled filtering arrangement  
A clock-controlled filtering arrangement for suppressing a number of interference frequencies related to a clock frequency, which comprises a time-discrete comb filter included in a negative...
Matches 1 - 50 out of 94 1 2 >