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1.
A new low sensitivity second-order bandpass digital filter structure is presented. The proposed structure has the smallest absolute angle, sensitivity and a moderate radius sensitivity for the pole angle &thetas; in the range 0.38π ⩽ |&thetas;| ⩽ 0.44π and 0.56π ⩽ |&thetas;| ⩽ 0.62π and for the radius in the range 0.5 ⩽ r < 1 相似文献
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The paper describes the solution to coefficient and product-quantization effects in a practical, real-time digital filter bank. The solution to the coefficient-quantization effects involves simple manipulation of the floating-point filter coefficients. A computer simulation of product-quantization errors enables the appropriate number of bits for the truncated products to be determined. 相似文献
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The quantization noise of a fixed-point digital filter is commonly expressed in terms of its noise gain, i.e., the factor by which the noise power q/sup 2//12 of a single quantizer is amplified to the output of the filter. In this brief, first a closed-form expression for the optimal second-order noise gain in terms of the coefficients of the numerator and denominator polynomials of the transfer function is derived. It is then shown, by deriving a similar expression for its noise gain, that the second-order direct form structure has an arbitrarily larger noise gain the closer the filter poles are to the unit circle. The main result, however, is that the wave digital form and the normal form structures have noise gains which are only marginally larger than the minimum gain. For these forms, the expressions for their noise gain in terms of the transfer function are given as well. The importance of these forms lies in the fact that they use less multipliers than the optimal structure and that they are much easier to design: properly scaled forms are given requiring no design tools. 相似文献
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A new adaptive second-order Volterra delay filter is developed to include the linear and quadratic filter coefficients for system modelling and identification. The filter structure is very effective in modelling second-order Volterra systems with sparse system coefficients 相似文献
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Universal filter using plus-type CCIIs 总被引:1,自引:0,他引:1
A universal second-order filter circuit with voltage gain using only plus-type current conveyors (CCIIs) is presented. The circuit offers several advantages, such as high input impedance, low filter sensitivities to passive elements, use of grounded capacitors and independent control of ω0, Q and voltage gain with separate grounded resistors. The use of only one type (plus-type or minus-type) of CCII simplifies the configuration 相似文献
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Providing voice and data communications to people away from their wireline telephones has become a major communication frontier. This frontier is being penetrated by evolving approaches to portable communications, e.g., cordless telephones, mobile radiotelephone, and radio paging. However, these approaches have many limitations; none can provide universal portable communications services. This paper discusses limitations of the evolving approaches and considers objectives and approaches for providing more universal digital portable communications as an integrated part of telephone exchange networks. These more universal communications could be accomplished by using demand-assigned radio links for the last thousand feet or so of telephone loops and sharing the remainder of the fixed distribution facilities. Fixed radio ports as integrated parts of telephone distribution networks could be placed throughout service regions. Efficient use of the radio spectrum could be insured by the planned reuse of radio frequencies throughout the regions. The severe multipath radio propagation environment within and around buildings that strongly influences the design of portable communications systems is described in the paper. System configurations and radio link techniques, that can provide reliable communications in the multipath environment, are discussed. Radio system calculations are illustrated for radio ports with 30-ft-high antennas in residential areas. The calculations indicate that radio link availability would be greater than 99 percent for 2000-ft port separations and 5-mW portable transmitters. Reuse of frequencies would require dividing the allocated frequency band into segments for use at adjacent ports. Calculations suggest that link availability in the cochannel interference environment would be greater than 99 percent, if 25 to 35 segments were used in residential areas. 相似文献
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A modified second-order infinite impulse response (IIR) notch filter with constrained poles and zeros is presented to eliminate or retrieve sinusoids embedded in a broadband signal. Such a filter is ideally suited to either parallel or cascaded implementation. Two classes of problems are considered. The first is where the sinusoidal frequencies are known a priori. For this case a straightforward design procedure based on a set of design characteristic graphs is used to select tunable notch filter parameters. An interesting property of the notch filter model is that it can be converted to a line enhancer by interchanging the position of the poles and zeros. The second type of problem arises when the sinusoidal frequencies are unknown and possibly varying with time. This means that an adaptive solution is required and an important consideration is the parameter estimation accuracy. For this purpose, the paper derives the Cramer–Rao lower bound for the adaptive cascaded notch filter using a frequency-domain approach. Some simulation results are included to demonstrate the effectiveness of the proposed adaptive notch filter. 相似文献
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Universal filter using two current-feedback amplifiers 总被引:3,自引:0,他引:3
A new universal filter using two current-feedback amplifiers is presented. This filter can realise lowpass, bandpass, highpass, notch and allpass filters from the same configuration. It has the following features: orthogonal control of the natural frequency and quality factor by grounded resistors, easy conversion into a voltage-controlled filter, minimum active components, without match components except for allpass applications, low active and passive sensitivities, and cascadability. Experimental results that confirm the theoretical analyses are obtained 相似文献
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A simple digital technique is described for prefiltering a signal to reduce aliasing errors in a subsequent main digital filtering operation. Unlike analogue prefilters, this new filter has a linear phase characteristic. 相似文献
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A novel quantisation strategy is found for the second-order wave digital filter proposed by Verkroost so that the filter possesses near-optimal noise performance and only exhibits very low amplitude limit cycles under constant input conditions. 相似文献
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This paper describes a robust scale-space filter that adaptively changes the amount of flux according to the local topology of the neighborhood. In a manner similar to modeling heat or temperature flow in physics, the robust scale-space filter is derived by coupling Fick's law with a generalized continuity equation in which the source or sink is modeled via a specific heat capacity. The filter plays an essential part in two aspects. First, an evolution step size is adaptively scaled according to the local structure, enabling the proposed filter to be numerically stable. Second, the influence of outliers is reduced by adaptively compensating for the incoming flux. We show that classical diffusion methods represent special cases of the proposed filter. By analyzing the stability condition of the proposed filter, we also verify that its evolution step size in an explicit scheme is larger than that of the diffusion methods. The proposed filter also satisfies the maximum principle in the same manner as the diffusion. Our experimental results show that the proposed filter is less sensitive to the evolution step size, as well as more robust to various outliers, such as Gaussian noise, impulsive noise, or a combination of the two. 相似文献
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提出了用多输出端电流模式全差分积分器(MCDI)实现二阶带通滤波器的方法。分析了输入级为PMOS管的MCDI及所提出的滤波器的特性,由该类型积分器所构成的滤波器,不仅具有较高的信噪比性能,而且能达到通过调节积分器的偏置电流值的大小能使得其所构成的带通滤波器的中心频率可在很宽的范围内调控的目的。应用台积电(TSMC)2层多晶硅、4层金属(2P4M)混合信号(mixed-mode signal)3.3V电源电压、0.35μ m、CMOS工艺参数仿真得到的带通滤波器的功耗仅为0.28mW左右,仿真结果表明滤波器设计正确、有效。 相似文献
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针对传统第二代电流传输器(CCⅡ)电压跟随不理想的问题,提出了新型第二代电流传输器(CCCⅡ)并通过采用新型第二代电流传输器(CCCⅡ)构成二阶电流模式带通滤波器,此滤波器只需使用2个电流传输器和2个电容即可完成设计。设计结构简单,其中心频率可由电流传输器的偏置电流控制。利用HSpice软件仿真分析并验证了理论设计的准确性和可行性。 相似文献
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Hua-Pin Chen 《Analog Integrated Circuits and Signal Processing》2007,50(2):137-139
Despite the extensive literature on current conveyor-based voltage-mode universal biquads with single input and multiple outputs,
no filter circuit has been reported to simultaneously achieve all of the advantageous features: (i) employment of only two
differential difference current conveyor (DDCC), (ii) employment only two grounded capacitors, (iii) employment only three
resistors, (iv) simultaneously realize voltage-mode low-pass, band-pass, high-pass, notch and all-pass filter signals from
the five output terminals, respectively, (v) orthogonal control of ω
o
and Q, (vi) low input impedance and can be cascadable (vii) no need to employ inverting type input signals, and (viii) no need
to impose component choice except realizing the all-pass filter signal. 相似文献
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Pipeline techniques have been successfully applied to speeding up processing in both general- and special-purpose digital computers. Application of these techniques to nonrecursive (FIR) filters has been suggested and is quite straightforward. Application to recursive (IIR) filters has not previously been shown. In this paper, the technique for applying pipeline techniques to recursive filters is shown and the advantages and disadvantages of the technique are discussed. Using these techniques, recursive digital filters operating at hitherto impossibly high rates can be designed.The basic research for this idea was supported by the Department of Electrical and Computer Engineering, University of California, Davis, California 95616. The basic idea is the subject of a pending patent application. Subsequent research was supported by the U.S. Naval Electronic Systems Command.On leave from the Department of Electrical and Computer Engineering, University of California, Davis, California 95616, USA. 相似文献