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.

A New Second-Order All-Pass Filter in 130-nm CMOS

Abstract: This brief presents a novel wide-bandwidth second-order voltage-mode all-pass filter derived from a canonical single transistor bandpass filter. The core of the circuit consists of only one transistor, two resistors, and two energy storage elements. The operation of the proposed filter is validated experimentally. A filter implemented in an IBM 0.13- $\mu\mbox{m}$ CMOS was measured to have a 55-ps group delay across a 6-GHz bandwidth while consuming 18.5 mW from a 1.5-V supply. This work experimentally demonstrates a CMOS all-pass filter that operates at multigigahertz frequencies and achieves the highest delay-bandwidth product compared to previously published CMOS all-pass filters known to the authors.

Low-Noise Low-Pass Filter for ECG Portable Detection Systems with Digitally Programmable Range

Abstract: This paper presents the design of an operational transconductance amplifier-C (OTA-C) low-pass filter for a portable Electrocardiogram (ECG) detection system. A fifth-order Butterworth filter using ladder topology is utilized to reduce the effect of component tolerance and to provide a maximally flat response. The proposed filter is based on a novel class AB digitally programmable fully differential OTA circuit. Based on this, PSPICE simulation results for the filter using 0.25-μm technology and operating under ±0.8 V voltage supply are also given. The filter provides a third harmonic distortion (HD3) of 53.5 dB for 100 mV p-p @50 Hz sinusoidal input, input referred noise spectral density of , total power consumption of 30 μW, and a bandwidth of 243 Hz. These results demonstrate the ability of the filter to be used for ECG signal filtering that is located within 150 Hz.

A 16-bit 250-kHz delta-sigma modulator and decimation filter

Abstract: This paper describes a delta-sigma analog-to-digital converter (ADC) capable of converting input frequencies up to 250 kHz. It consists of a fifth-order switched-capacitor delta-sigma modulator and a decimation filter. Various design optimizations in the modulator are presented. The decimation filter consists of a comb filter followed by a novel, highly efficient and scalable finite impulse response filter. The ADC was implemented in 0.6-/spl mu/m CMOS technology. It achieves a dynamic range of 94 db.

A new method of passive harmonic filter planning for controlling voltage distortion in a power system

Abstract: This paper presents a new method for planning single-tuned passive harmonic filters to control harmonic voltage and voltage distortion throughout a power system. Several alternative objective functions are considered as performance indices in the filter planning problem while the IEEE-519 individual and total harmonic voltage distortion limits at each network bus, as well as filter component limits, are modeled as constraints. The tuned frequency deviation of the filter caused by component manufacturing errors and environmental changes is also taken into account. To solve the problem, a two-step procedure is first proposed to place the filters. Next, the planning problem is formulated as a constrained optimization problem for minimizing the defined network objective function and is then solved by a genetic algorithm-based optimizer to obtain the optimal size of each filter component. The usefulness of the proposed method is tested with an actual distribution network. Results show that the method is effective, computationally robust, and is suitable for the passive filter planning in a power system.

Wireless receiver with notch filter to reduce effects of transmit signal leakage

Abstract: This disclosure describes techniques for reducing adverse effects of TX signal leakage in a full-duplex, wireless communication device. The techniques make use of a notch filter to reject TX signal leakage in a signal processed in the RX path of the wireless communication device. The notch filter may be constructed as a complex notch filter using passive resistor and capacitor components to produce a notch frequency that attenuates TX signal leakage components in a desired signal. The notch filter may be applied to a down-converted, baseband signal produced by a passive mixer.