Showing papers on "Stopband published in 1981"
TL;DR: Chebyshev gain functions have been widely employed for tly, matching a complex load to a resistive generator as discussed by the authors, and such transfer functions do result in optimum response when the terminations are purely resistive.
Abstract: Chebyshev gain functions have been widely employed for tly, matching a complex load to a resistive generator. Such transfer functions do result in optimum response when the terminations are purely resistive. However, assuming the overall transducer gain characteristic has monotone decreasing stopband behavior, the equal ripple transfer function is shown to be not optimum for a complex load. Furthermore, equalizers simpler in structure and superior in frequency response to equal ripple designs can readily be synthesized. Indeed it appears that nonoptimality will generally result whenever analytic gain-bandwidth theory is used to determine the constants of a transfer function belonging to an a priori specified class. Examples are presented for the matching of LCR and CR loads.
85 citations
TL;DR: In this paper, the design and analysis of switched-capacitor filters of the state variable or "leapfrog" type is presented in which the sampling rate may be as low as twice the highest frequency of interest.
Abstract: The design and analysis of switched-capacitor filters of the state variable or "leapfrog" type is presented in which the sampling rate may be as low as twice the highest frequency of interest. The effects due to the sampled data nature of the signals are fully taken into account and an exact synthesis is derived. This allows the sampling rate to be treated as a design parameter which Influences the maximum attenuation level in the stopband and the required capacitance ratios.
51 citations
TL;DR: In this paper, a dielectric waveguide with periodic metallic strips suitable for millimeter-wave and sub-millimeter wave integrated circuits is analyzed by a rigorous formulation, and the accuracy of the solution of the analysis can be systematically improved by increasing the size of the matrix associated with the eigenvalue equation.
Abstract: A dielectric waveguide with periodic metallic strips suitable for millimeter-wave and submillimeter-wave integrated circuits is analyzed by a rigorous formulation. The accuracy of the solution of our analysis can be systematically improved by increasing the size of the matrix associated with the eigenvalue equation. Stopband properties are numerically presented as a function of the spacing and width of metallic strips and dielectric profile. It is found that there is a difference in the stopband properties of TM and TE modes. Experimental results for the band reject filter are also presented to verify the validity of our analysis.
23 citations
01 Jan 1981
TL;DR: In this paper, an analysis of X-polarized horizontal shear surface wave propagation on rotated Ycut quartz and berlinite corrugated surfaces was performed using Datta-Hunsinger perturbation theory.
Abstract: An analysis has been performed of X-polarized horizontal shear surface wave propagation on rotated Ycut quartz and berlinite corrugated surfaces. Space harmonic theory is used, with the effect of the corrugated surface grating analysed by Datta-Hunsinger perturbation theory. Dispersion curves are given, showing the influence of crystal orientation, grating depth and sample thickness. Scattering coefficients for a finite length stopband grating in an infinite passband grating line are evaluated using a modification of the Kogelnik-Schmidt theory for finite SAW gratings. Experimental results are presented and the potential of these structures for surface wave resonator applications is discussed,
14 citations
TL;DR: In this article, a method for determining the transfer function of recursive digital low-pass filters with a Chebyshev characteristic of attenuation in the stopband and phase or group delay specifiable independently of the attenuation is presented.
Abstract: A method is presented for determining the transfer function of recursive digital low-pass filters with a Chebyshev characteristic of its attenuation in the stopband and phase or group delay specifiable independently of the attenuation. If the maximally flat criterion is chosen for the approximation of a prescribed constant group delay, the transfer function will be obtained in an explicit form. In other cases, the group delay or phase prescription must first be approximated numerically, while the attenuation property can always be achieved explicitly without numerical optimization. A peculiarity of the method is that, in opposition to analog filters, one can obtain for a specific phase or group delay property several transfer functions, which differ in the numerator polynomial and thus in the minimum value of the attenuation in the stopband. The results will be demonstrated with the aid of an example.
8 citations
TL;DR: In this article, a range of orientations of lithium niobate substrates is shown both theoretically and experimentally to give very good rejection of spurious bulk wave signals in the stopband of a SAW TV filter and other SAW filters of similar bandwidth.
Abstract: A range of orientations of lithium niobate substrates is shown both theoretically and experimentally to give very good rejection of spurious bulk wave signals in the stopband of a SAW TV filter and other SAW filters of similar bandwidth.
7 citations
21 Sep 1981
TL;DR: In this paper, a +θ° rotated Y-cut X-propagating lithium niobate substrate with θ in the range from 121° to 127° was used to reduce the degradation of the filter upper stopband.
Abstract: Surface acoustic wave bandpass transversal filters, eg television intermediate frequency filters, comprising a +θ° rotated Y-cut X-propagating lithium niobate substrate with θ in the range from 121° to 127°, preferably 123° to 125° For a suitable range of filter bandwidths (35 db bandwidth between 005 and 05) these substrates provide reduced degradation of the filter upper stopband predominantly due to indirect bulk shear waves in the frequency range from the passband up to the frequency where direct bulk longitudinal wave degradation becomes significant This frequency range is 415 MHz to approximately 55 MHz for a UK system tv if filter and is 6025 MHz to approximately 90 MHz for a Japanese system tv if filter
5 citations
01 Apr 1981
TL;DR: In this article, a method for obtaining the parameters of a maximally flat sharp cutoff low-pass filter with coincident multiple transmission zeros is given, which satisfies arbitrary passband and stopband specifications.
Abstract: A method is given for obtaining the parameters of a maximally flat sharp cutoff low-pass filter with coincident multiple transmission zeros, which satisfies arbitrary passband and stopband specifications.
4 citations
01 Jan 1981
TL;DR: In this article, it was shown that a 21.8 pm wavelength Sezawa surface wave through an 8.1 pm aluminum grating multistrip coupler exhibited a narrow stopband.
Abstract: The high electromechanical coupling of the Sezawa mode makes it feasible to construct devices such as a multistrip coupler in the metal-Zn0-SiOz-Si surface acoustic wave configuration. The transmission of a 21.8 pm wavelength Sezawa surface wave through an 8.1 pm aluminum grating multistrip coupler, however. exhibited a narrow stopband. This stopband has been identified as resulting from a conversion of the Sezawa mode to the Rayleigh mode. Clearly, the mode conversion must be taken into account in the design of periodic grating structures, such as a multistrip coupler, to avoid spurious stopbands. The conversion also provides a new phenomenological basis for the construction of narrow bandpass filters.
3 citations
01 Jan 1981
TL;DR: In this article, a new range of cuts of lithium niobate for which bulk-wave signals a re weakest at the frequencies where maximum suppression of spurious level is required is presented, and the theoretical basis of this choice and the results of more extensive experimental verification are presented.
Abstract: Degradation of the stopband by spurious bulkwave signals is a major problem in the design of SAW bandpass filters. Several schemes exist for reducing the problem but all involve a penalty in terms of production cost. Low bulk-wave substrate orientations have been previously sought, but incorrect criteria have led to non-optimum cuts. We have recently (ref.1) r eported a new range of cuts of lithium niobate for which bulk-wave signals a re weakest at the frequencies where maximum suppression of spurious level is required. Choice of cut angle is shown to be a function o f bandwidth and shapefactor. In t his paper we present more details of the theoretical basis of this choice and the results of more extensive experimental verification.
3 citations
01 Jan 1981
TL;DR: A monolithic Chebyshev CCD wave filter with a center frequency of f o = 50kHz and a relative bandwidth of 4.2, 5dB insertion loss and 60dB stopband attentuation was described in this article.
Abstract: A monolithic Chebyshev CCD wave filter with a center frequency of f o = 50kHz and a relative bandwidth of 4.2%, 5dB insertion loss and 60dB stopband attentuation will be described.
TL;DR: In this article, the authors derived an approximation to the resonator coupling coefficient and compared the effect of the phase inverter on the center frequency of the filter with rigorously obtained data, and then they analyzed the transfer characteristics of the MCF based on the present design procedure, which can improve the symmetry of the attenuation in the stopband.
Abstract: Nuch has been reported on the analysis and design of the quartz monolithic crystal filter (MCF). Since the mechanical coupling between contiguous energy trapping resonators is dependent on the cutoff mode, the propagation phase is independnet of the resonator spacing. This paper analyzes the MCF with phase inverting electrodes and establishes a design method for solution to the above restriction. First, we derive an approximation to the resonator coupling coefficient and compare the effect of the phase inverter on the center frequency of the filter with rigorously obtained data. Next, we study the effect of unwanted modes on the transfer characteristics of the filter. Finally, we describe the design method and compare the data with experimental values. The optimum values of the width of the phase inverter and of the decrease in frequency are given in terms of the resonant frequency and the frequency reduction of the resonator. These relations are summarized in graphical form to facilitate the design. The phase inverter tends to increase the center frequency of the filter and the amount of increase must be taken into account in the design stage. By studying the transfer characteristics of the MCF based on the present design procedure, we can improve the symmetry of the attenuation in the stopband.
TL;DR: The passive CCD resonator is a recursive CCD building block which is well suited for the realization of high Q bandpass filters and is compatible with the standard double-poly NMOS technology.
Abstract: The passive CCD resonator is a recursive CCD building block which is well suited for the realization of high Q bandpass filters. Its realization is compatible with the standard double-poly NMOS technology. Advantages of the new approach are an extremely low sensitivity of the center frequency which is determined by an external clock frequency, a relative bandwidth which does not depend on the center frequency but is controlled by a capacitance ratio, and signal frequencies at least up to some hundred kHz. The analysis, design considerations, and performance results are presented. A loaded Q factor of 30, a maximum stopband attenuation of 26 dB, and a negligible insertion loss in the passband are typical for a single CCD resonator. The maximum overall center frequency deviation /spl Delta/f/f due to fabrication tolerances is proportional to the transfer inefficiency of the CCD and has the value of about 2/spl times/10/SUP -4/.
01 Jan 1981
TL;DR: In this paper, a split open metal strip array (S-OMSA) was proposed to improve the reflectivity and wide stop band for strongly piezoelectric substrate materials.
Abstract: A new type of reflector which we call split open metal strip array (S-OMSA) is described. This S-OMSA has the principal advantages of efficient reflectivity and wide stop band for strongly piezoelectric substrate materials. We have derived the reflection coefficient of S-OMSA in closed form by applying the image parameter theory to equivalent circuit model. Experiments were done on LiNb03 (128O rot.Y, X-prop.) to verify the theory. Finally, the distortionless resonance characteristics of one- and two port resonators utilizing these S-OMSAs are shown.
TL;DR: In this paper, intersection filters are proposed for general decimation/interpolation by rational factors, where the intersections of stopbands are intersections of the stopbands required in the case of integer factors.
Abstract: Optimum multiple stopband FIR filters for decimation or interpolation by integer factors have been presented in the literature. In this correspondence we extend these results to the case of general decimation/interpolation by rational factors. The resulting filters are called intersection filters because their stopbands are intersections of the stopbands required in the case of integer factors. Significant improvement in stopband attenuation is found in many cases for band-limited signals.
TL;DR: In the letter an implementation technique is proposed which reduces this coefficient sensitivity of CCD transversal filters and also offers other performance advantages.
Abstract: Charge-coupled-device (CCD) transversal filters are most commonly implemented using the split-electrode technique. Tap-weight accuracy is a major factor limiting the performance (stopband attenuation in particular) of these devices. In the letter an implementation technique is proposed which reduces this coefficient sensitivity and also offers other performance advantages.
TL;DR: In this article, a new application of PIN diodes is described in terms of a meander-line switchable filter, which is intended for use in multiplexing systems.
Abstract: A new application of PIN diodes is described in terms of a meander-line switchable filter. With the diodes forward-biased, bandpass properties result, but under reverse bias the passband is converted into a stopband. These filters are intended for use in multiplexing systems.
TL;DR: In this article, the propagation characteristics of the TM mode wave in a two-dimensional dielectric slab with a sinusoidal corrugation are theoretically analyzed and a coupled-mode equation is derived for describing the coupling between the forward and backward waves near Bragg frequency caused by the corrugations.
Abstract: The propagation characteristics of the TM mode wave in a two-dimensional dielectric slab with a sinusoidal corrugation are theoretically analyzed. A coupled-mode equation is derived for describing the coupling between the forward and backward waves near Bragg frequency caused by the corrugation and the Brillouin diagram is clarified. The theoretical characteristics of the reflection filter made of a dielectric slab with a finitely long corrugation are investigated. Using a Teflon slab loaded with a rectangular corrugation, experiments are conducted on the reflection filter in the 40-GHz band and the results are compared with theoretical values. It is found that such filter characteristics as the Bragg frequency, return loss and stopband half-width agree well with theoretical predictions.