Voltage-controlled filter

About: Voltage-controlled filter is a research topic. Over the lifetime, 5514 publications have been published within this topic receiving 70872 citations. The topic is also known as: VCF.

Variable rate digital filter

Abstract: A variable digital filter employs a variable rate sample clock with combinations of various digital filter elements such as an efficient implementation of decimation to achieve various filter realizations allowing a selectable output bandwidth. More specifically, a digital filter apparatus is coupled to receive input analog signals from a fixed anti-aliasing analog filter and optionally includes one or several stages of digital decimation filters, a low-pass filter, an optional equalizer, and an optional high-pass filter each of which may be programmed so as to configure the device with a variety of transfer characteristics. The filter device employs an input sample clock in the range of F-K*F, where, in a specific embodiment K is selected to be 2. The selectable combination of elements and stages used to form the filter needed is operative at a broad range of sample rates over a predetermined bandwidth range without loss of resolution. An extremely simple digital filter with a bandwidth of 1/4 the input sample rate is also shown.

Apparatus and method for filtering voiceband and metering tone frequencies of a mixed voice/data signal

Abstract: An apparatus and method provide for filtering of voiceband and specified tone frequencies of a mixed voice/data signal, such as an Asymmetric Digital Subscriber Line (ADSL) signal. A lowpass filter section passes voiceband content of the mixed signal and suppresses mixed signal content having frequencies falling within a databand of the mixed signal. A bandpass filter section is coupled to or integral with the lowpass filter section and passes the specified tone frequency, such as a metering or billing tone frequency. The lowpass and bandpass filter sections exhibit a combined frequency response that provides for a stopband between the voiceband and the metering tone frequency. The bandpass filter section effectively detunes a frequency response of the lowpass filter section to provide for the stopband. The stopband preferably provides for an insertion loss of 3 dB or greater between the voiceband and the metering tone frequency, and suppresses undesirable mixed signal content having frequencies falling within the stopband. The lowpass filter section and the bandpass filter section may each be implemented to include only passive components, such as passive magnetic components.

A 2.5 GHz Low Power, High- ${Q}$ , Reliable Design of Active Bandpass Filter

Abstract: In this paper, a variation-aware and reliable design of a fully integrated radio frequency (RF) bandpass filter realized using a voltage differencing transconductance amplifier is presented. The filter is characterized by its high frequency operation, low power consumption, high quality factor, and it is insensitive to process, voltage, and temperature variations. Sensitivity analysis has been performed to analyze the circuit performance in the presence of parasitics. The inductor-less approach finds its application in integrated building blocks of RF front ends, thus eliminating the requirement of off-chip filters in transceivers. Centered at 2.511 GHz and operating within the 36.21 MHz 3-dB bandwidth, the filter draws 0.168 mA from a ±1 V power supply, attains a voltage gain of 72.6 dB, a quality factor of 69.34 and noise figure of ~29.6 dB. In addition, it has a dynamic range of 125.84 dB-Hz and a 1-dB compression of −1.5 dBm which translates into a figure of merit as high as 94 dB.

Analysis of the design space of single-stage and two-stage LC output filters of switched-mode AC power sources

Abstract: This paper proposes a systematic approach to design the output filter of a 10 kW, low-voltage 400 V ll,rms , fouroutput phase, hard-switched AC source based on the Three-Level Neutral Point Clamped Voltage Source Converter topology. Given specifications of the AC source, such as the voltage quality, the control performance or the conducted EMI at the output of the source, are translated into corresponding families of curves in the parameter space of the output filter. The area/volume enclosed by these curves represents the design space of the output filter in which all tuples (L f , C f ), e.g. for a single-stage LC-filter, fulfill every single AC source specification. From all possible filter parameters in the design space, the set of parameters resulting in the smallest filter volume, the lowest filter weight, the highest filter efficiency and/or the lowest filter costs can be selected.

Novel Dual-band Bandpass Filter Design Using Microstrip Open-loop Resonators

Abstract: This paper presents a novel dual-band banpass filter using microstrip open-loop resonators. A new microstrip unit of dual-band bandpass filter is introduced, which can be used as unit element of duan-band filter design. The two open-loop resonators are treated as passband resonator and stopband resonator in analysis, respectively. A five-pole C-band dual-band bandpsss filter has been designed and fabricated. The measured results show a good agreement with the simulated results.