Electronic filter

About: Electronic filter is a research topic. Over the lifetime, 13207 publications have been published within this topic receiving 93063 citations. The topic is also known as: filter.

Reduced vlf overload susceptibility active noise cancellation headset

Abstract: The susceptibility of an active noise cancellation system to overloading due to very low frequencies is reduced by subtracting the low frequency components of an applied noise field from the residual signal. Low frequency components of the applied noise field outside the normal range of human hearing are detected by an external sensor (14) and isolated by a filter circuit (15). The isolated low frequency signal is subtracted from the residual signal, resulting in a modified residual signal with reduced low frequency components. The cancellation system thus eliminates very low frequency cancellation signals, without sacrificing bandwidth or system performance within the audible range.

Extremely low sensitivity active RC filter

Abstract: A new active RC bandpass filter containing two resistors, two capacitors, and two voltage amplifiers is presented. The Q sensitivities of the filter with respect to the passive elements can be made zero, and the Q sensitivities with respect to the gains of the amplifiersare less than one half.

Surface acoustic wave filter

Abstract: Disclosed is a SAW filter employing a SAW resonator which is constructed of a plurality of pairs of electrode fingers formed on a piezoelectric substrate, and in which a plurality of SAW transmission spaces are included. The SAW transmission spaces do not have the function of exciting a SAW, and they have electric lengths which match the phases of SAWs excited by the resonator. In accordance with frequency characteristics required of the filter, such SAW transmission spaces are introduced into, for example, one of a plurality of SAW resonators located on the electric power input side of the filter.

Hybrid active power filter with programmed impedance characteristics

Abstract: A hybrid active power filter having programmed impedance characteristics is presented. In accordance with which, a passive device comprising a capacitor CF is connected in series with an active device which are together connected in shunt with a power source and a load at transmission lines of a power system. Capacitor CF substantially supports the full-line voltage VH of the power source, whereby the active filter is exposed to a substantially lower voltage than the line voltage VH. The active device includes on active filter, i.e., an inverter current regulator with a programmable controller for executing a control algorithm. The controller of the active device receives signals corresponding to a voltage VM, at the low side of filter capacitor CF. Voltage VM is at a substantially lower voltage than the line voltage VH, whereby the cost of sensing voltage VM is significantly less than sensing the high line voltage V.sub.. The control algorithm of the present invention is expressed as ##EQU1## where IA is the current in the active device and YFAo is an order transfer function of the effective admittance of the active device. YFAo is a continuous function which is defined to provide a low impedance path at desired frequencies. Accordingly, the control algorithm controls the current IA in response to voltage VM sensed at the low side of filter capacitor CF as dictated by the programmed function. The active device may be connected to the passive filter at a junction between two capacitors or at a junction between two inductors.