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.

An investigation on the selection of filter topologies for passive filter applications

Abstract: Passive filters have been a very effective solution for power system harmonic mitigation. These filters have several topologies that give different frequency response characteristics. The current industry practice is to combine filters of different topologies to achieve a certain harmonic filtering goal. However, there is a lack of information on how to select different filter topologies. This decision is based on the experience of present filter designers. The goal of this paper is to investigate the filter topology selection issue. It presents our research results on the effectiveness and costs of various filter topologies for harmonic mitigation. The research results show that the association of three single-tuned filters is a very appropriate solution for most typical harmonic problems.

Activity monitoring apparatus with configurable filters

Abstract: An activity monitor adapted to be worn on the non-dominant wrist of a subject includes a bimorphous beam motion sensor. The output signal of the sensor is amplified in an amplifier circuit having a selectable amplification factor, and filtered by highpass and lowpass filter circuits having individually selectable cut-off frequencies to obtain an analog signal for processing having a bandpass and amplitude characteristic corresponding to a particular body activity under observation. A control and processing circuit within the monitor includes a microprocessor which responds to either resident internal operating instructions or to externally supplied operating instructions, or to designated data signal parameters, to provide configuration control signals to the amplifier and filter circuits, and processing of the collected data, appropriate to the particular activity being monitored. The processed data is digitally stored in an internal memory for subsequent transfer through a data port to an associated computer for display or further processing.

A Fifth-Order Continuous-Time Delta-Sigma Modulator With Single-Opamp Resonator

Abstract: Conventional continuous-time (CT) delta-sigma (??) analog-to-digital converters (ADCs) consume large amount of power in operational amplifiers of a loop-filter. We propose a new loop-filter with single-opamp resonator, ringing-relaxation filter and passive resistor adder to lower power consumption. These three techniques are essential for designing high-order delta sigma modulators with low oversampling ratio. Because the new resonator reduces the number of opamps, the resistor adder displaces a conventional active adder and the ringing-relaxation filter alleviates the burden on the first opamp by reducing its gain bandwidth, FOM is greatly improved. To demonstrate the concept, 300 MHz, fifth-order low-pass, 3-bit CT?? ADC of single feedback with feedforward architecture was implemented in a 1.1 V, 110 nm 1P6M CMOS process. An SNR of 68.2 dB and an SNDR of 62.5 dB were measured in a 10 MHz bandwidth and FOM was 0.24 pJ/conv.

Ring Resonator Bandpass Filter With Switchable Bandwidth Using Stepped-Impedance Stubs

Abstract: This paper presents a novel ring resonator bandpass filter (BPF) with switchable passband bandwidth. Simple techniques for analyzing resonant frequencies and transmission zeros are shown, and the methods of designing the lengths of open, stepped-impedance stubs attached to the ring are introduced to obtain the tunability of the bandwidth. Interdigital-coupled feed lines are used for harmonic suppression by adding transmission zeros outside of the passband, resulting in wide upper and lower stopbands. After the lengths of the open stubs and the design of the feed lines are decided, the means of producing the bandwidth tunability are analyzed. By changing the characteristic impedances of the open stubs, mid-upper or mid-lower passband bandwidths can be separately varied. Simultaneous increases or decreases of each width of the stepped open stubs change the number of resonances, resulting in wide or narrow passband bandwidths. The measured results of the BPF using PIN diodes show that the tunable passband ratio is 1.22:1.13:1 with a maximum insertion loss of 1.35 dB.

An MSI Micromechanical Differential Disk-Array Filter

Abstract: A medium-scale integrated (MSI) vibrating micromechanical filter circuit that utilizes 128 radial-mode disk and mechanical link elements to achieve low motional resistance while suppressing unwanted modes and feedthrough signals has been demonstrated with a 0.06%-bandwidth insertion loss less than 2.5 dB at 163 MHz. The ability to attain an insertion loss this small for such a tiny percent bandwidth on chip is unprecedented and is made possible here by the availability of Q's >10,000 provided by capacitively transduced resonators. In particular, the MSI mechanical circuit is able to harness the high Q of capacitively transduced resonators while overcoming their impedance deficiencies via strategic mechanical circuit design methodologies, such as the novel use of wavelength-optimized resonator coupling to effect a differential mode of operation that substantially improves the stopband rejection of the filter response while also suppressing unwanted modes.