General Parameter Filter Research Articles

Spatial-Temporal Non-Uniform Subband Broadband Beamforming

A spatial-temporal scheme based on non-uniform subband general parameter filter banks for broadband beamforming of scaled aperture array is proposed in this paper. The scaled aperture array is composed of several uniformly-spaced linear subarrays, each of which processes an octave subband signal respectively. The non-uniform subband signal is implemented by tree-structure general parameter filter banks. Each subarray broadband beamforming is carried out by a kind of tapped-delay-line (TDL) infinite-impulse-response (IIR) filters beamformer, and four subarrays share the same weights. This processing architecture based beamformer splits the broadband signal into several narrower subband ones which are processed in parallel, and subarray is operating with lower sampling rate, which contributes to decreasing the computational load significantly and improving the speed and performances as well. Simulations show that computation complexity and load of this beamformer are much lower relative to the conventional TDL broadband beamfomer.

Exact design of switched-capacitor bandpass filters using coupled-biquad structures

A method is presented for the design of switched-capacitor bandpass filters using the bilinear z -transform. The filters are realized in low-sensitivity coupled-biquad structures and employ biquad circuits which are completely insensitive to stray capacitances between any node and ground. Geometrically symmetric (both all-pole and finite-transmissionzeros) as well as general-parameter filters are treated.

Computer-aided design of transmission-line filters

Computer-aided design techniques used for design of lumped general parameter filters are extended to design transmission-line filters of commensurate length having both cascaded and shunted lines. Starting from the characteristic equation a sot of algebraic equations are obtained in terms of relative errors in the line impedances. By a proper interpretation of the errors the characteristic impedances are adjusted to obtain the desired filter.

Transient response of cascaded networks using numerical inversion of the Laplace transform

Time-domain analysis of general parameter filters is carried out by first analysing the circuit in theS–domain for integer values ofSand then using numerical inversion of the Laplace transform to obtain transient response. The inversion technique follows the line given by Bellman et al. (1966) and leads to solution of the Fredholm integral equation of the first kind. The method in applied to time-domain analysis of second-order systems and to general parameter filters.

Family of equiripple lowpass digital filters

The letter deals with the special case of general-parameter filters that yield Cheby̅shev characteristics. The solution gives a family of Cheby̅shev responses with monotonic stopband and equiripple passband characteristics. These characteristics belong to combinations of the sin (ωT/2) and tan (ωT/2) formulations and it is shown that under the condition of maximum sharpness at cutoff the tan (ωT/2) formulation is unique.

The synthesis of general parameter insertion loss filters using a digital computer

A problem often encountered in practical network design is the synthesis of filters which satisfy various frequency-dependent requirements in the stop band and exhibit Tchebyshev behavior in the pass band. The theory of such networks, usually called general parameter filters, was founded by Darlington1 and treated in detail by German authors. <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2^{‾⁴ As the amount of numerical calculations encountered in the design process is considerable even for the simplest cases and becomes excessive for the more involved networks, the need for a digital computer is strongly indicated. As will be pointed out later, a digital computer supplies the fastest and most economical way of design.}</sup>