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.

Multilayer suspended stripline and coplanar line filters

Abstract: Using metallization patterns on both sides of a suspended stripline substrate or adding an additional dielectric and conductor layer to coplanar line circuits, additional degrees of freedom arise for filter design like an extended range of impedances, tightly coupled line structures or increased end coupling between lines of different metallization layers. In this way, very compact filter circuits with improved performances may be realized as it is shown for different types of filters using this technique, even including active elements to realize strongly frequency selective amplifiers or active filters. >

MOS ADC-filter combination that does not require precision analog components

Abstract: AN OVERSAMPLE-AND-DECIMATE ARCHITECTURE yielding a analog-to-digital interface system with a built-in maskprogrammable digital antialias filter in standard 5V digital MOS technology will be reported. Unlike other MOS A/D converter techniques, this approach requires no precision component ratios or precision comparator, nor a double-polysilicon or other special capacitor structure. Prototype devices display approximately 12b converter linearity at an 8kHz output rate with a single 5V power supply and a total die area of 4 8mm? The low supply voltage and simplified process requirements are attractive for scaled MOS fabrication technologies. This is intended as a linear (non-companding) analog-interface block for constant-sampling-rate applications uch as speech processing. The system is based on l b A/D conversion, downsampled 256 times by a 1024-point, finite-impulse-response (FIR) digital lowpass filter. Such a configuration can display a net resolution exceeding the performance of the internal analog components, and since the bulk of the circuitry is digital, it benefits from continued technology scalmg. It differs also from interpohtiue A/D circuits’, in that it requires no internal D/A converter, nor does it produce a coarser quantization with larger inputs. A delta-sigma-modulator front end, used elsewhere in disCrete2, bipolar3 and passive grounded-capacitor MO!? circuitry, has been realized with a parasitic-insensitive switchedcapacitor integrator; Figure 1. The parasitic insensitivity allows

Sigma delta modulator

Abstract: A separate filter circuit is inserted between the D/A converter and the summing junction in the feedback path of a conventional sigma delta modulator. This additional filter allows control of the quantization noise transfer function profile independently of the forward signal transfer function. By proper tailoring of the transfer functions a third or higher order modulator can be constructed without instability developing. The modulator can also be constructed as a completely digital circuit and used as a noise shaping circuit in a digital digital-to-analog converter.

Inductorless bandpass filters

Abstract: The technique of designing inductorless filters by replacing the inductors in conventional LC filters with gyrators and capacitors is considered for the special case of the high-quality channel bandpass filters used in multiplex telephony. One particular gyrator circuit, which has been found to be very satisfactory, using two operational amplifiers and four resistors, is analyzed in some detail. The difficulties of simulating floating inductors are discussed, and ways of designing filters to avoid the necessity of such simulations are proposed. The dynamic range of a filter is defined and the factors controlling it are described. Detailed measured results of two specific channel filter designs are included.

Experimental verification of dominant harmonic active filter (DHAF) for high power applications

Abstract: A synchronous reference frame (SRF) based controller for a dominant harmonic active filter (DHAF) system has been proposed previously by the authors (1996, 1998). The SRF controller is designed to achieve harmonic isolation at the dominant harmonic frequencies (such as the 5/sup th/ or the 7/sup th/) between supply and load. Such design allows implementation of the DHAF system by square-wave inverters switching at the 5/sup th/ and 7/sup th/ harmonic frequencies. Compared to the conventional active filter systems which require high switching frequency PWM inverters for implementation, the square-wave inverter based DHAF system is more viable and cost-effective for high power nonlinear load (10 MW and above) or cluster of nonlinear loads to meet the IEEE 519 harmonic standard. In this paper, a new feedforward command of the SRF controller is proposed to provide better dynamic performance. If the resonance of source impedance and passive filter bank occurs near the dominant 5/sup th/ or 7/sup th/ harmonic frequency, the amplification effect at the harmonic frequencies will cause severe distortion in the supply current. The improved feedforward command of the SRF controller is able to suppress the resonance and meet the requirement of IEEE 519 harmonic standard. Experimental results are also presented in this paper to validate the effectiveness of the SRF controller and the square-wave inverter based DHAF system.