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.

Study on a Novel Hybrid Active Power Filter Applied to a High-Voltage Grid

Abstract: A novel hybrid active power filter (HAPF) applied to a high-voltage grid is proposed. The passive filter of this topology can be used for reactive power compensation as well as for harmonic mitigation caused by the nonlinear load. The active power filter, which is shunted to a fundamental resonance circuit, is connected in series with a matching transformer, thus forming the injection-type hybrid active power filter. Because of this advantage, it is effective to be used in the high-voltage distribution grid. The basic principle of this topology is introduced particularly. Then, the steady compensation characteristic and the resonance-damping characteristic of this system are analyzed in detail. The principle about the designing method of HAPF is proposed. A HAPF prototype with the proposed designing method was built, and installed in a copper plan in Southern China. Experimental and application results prove that the proposed HAPF is good in harmonics elimination, reactive power compensation, and reliability.

Modeling and stability analysis of active/hybrid common-mode EMI filters for DC/DC power converters

Abstract: Hybrid electromagnetic interference (EMI) filters (HEFs) which are composed of an active filter and a passive filter, have been proposed to reduce the size and weight of conventional passive EMI filters. However, accurate models that can be used to predict the stability and performance of HEFs have not been developed. To cope with this, this paper presents a modeling technique for a hybrid common-mode (CM) filter. The technique can be applied to the modeling of other HEFs. Critical component models were first developed for the HEF. HEF's overall model is further developed based on these individual component models. Experimental results validated that the developed model can successfully predict the stability and performance of the hybrid CM filter.

A Low-Power WCDMA Transmitter with an Integrated Notch Filter

Abstract: In a WCDMA FDD system, since the transmitter and receiver operate concurrently, the receiver is plagued by the transmitter leakage due to finite isolation of antenna duplexer. As a consequence, the transmitter noise at the receive band degrades the sensitivity, unless the noise is further attenuated before reaching the receiver. Due to the modest Q of on-chip inductors, typically the use of a costly SAW filter placed before the PA is inevitable. On the other hand, the external filter may be eliminated through sufficiently lowering the transmitter noise for any given duplexer. However, given the power-noise trade off, in all previous designs due to the lack of an on-chip filtering mechanism, meeting the stringent noise requirement has resulted in an excessive transmitter power dissipation. To address these issues, a feedback-based filtering technique to suppress the receive-band noise with negligible area or power penalty is presented. Stability analysis reveals that with practical transmitter gain distribution, optimum component sizes, and for a typical required noise suppression, using a simple first- or second-order RC LPF, the feedback remains stable and no additional compensation is required.

Adaptive speech filter

Abstract: An adaptive speech filter ( 10 ) for conditioning speech signals to increase signal to noise ratio in a relatively noisy environment. The adaptive speech filter ( 10 ) has a preamp circuit ( 12 ), a high pass adaptive filter circuit ( 14 ), an output buffer circuit ( 16 ), a peak detector amplifier/filter circuit ( 18 ), a peak detector circuit ( 20 ) and a voltage regulator circuit ( 22 ), embodied in an application specific integrated circuit ( 24 ). The adaptive speech filter ( 10 ) is intended for input to telephones, radios, and the like.

Electric Coupling Structure of Substrate Integrated Waveguide (SIW) for the Application of 140-GHz Bandpass Filter on LTCC

Abstract: Millimeter-wave (mmW) bandpass filters (BPFs) using substrate integrated waveguide (SIW) are proposed in this paper. The propagation constants of two different types of electromagnetic bandgap (EBG) units are discussed and compared for their passbands and stopbands performance. In among, the slotted-SIW unit shows a very good lower and upper-stopband performance. The mmW BPF with three cascaded uniform slotted-SIW-based EBG units is constructed and designed at 40-GHz. This EBG filter exhibits good out-of-band performance. To further improve the in-band performance, a third-order mmW BPF with nonuniformly cascaded slotted-SIW unit is designed at 140 GHz. The filter is investigated with the theory of electric coupling mechanism. The extracted coupling coefficient (K) and quality factor (Q) are used to determine the filter circuit dimensions. To prove the validity, the two proposed structures are fabricated in a single-circuit layer using low temperature co-fired ceramic technology and measured at 40 and 140 GHz, respectively. The measured results are in good agreement with the simulated results in such high frequency. The measured insertion losses at 40 GHz and 140 GHz are 0.72 and 1.913 dB, respectively.