A synthesis technique is presented for the multiple feedback (MF) active RC realization of transfer functions having complex frequency transmission zeros, and a biquadratic block in the MF structure is proposed, which is suitable for realizing the internal transfer function having complex zeros and poles.

An adaptive algorithm for a single sinusoid detection using IIR bandpass filter with parallel block structure has been proposed by Nishimura et al. However, the algorithm has three problems: First, it has several input frequencies being impossible to converge. Secondly, the convergence rate can not be higher than that of the scalar structure. Finally, it has a large amount of computation. In this paper, a new algorithm is proposed to solve these problems. In addition, a new structure is proposed to reduce the amount of computation, in which the adaptive control signal generator is realized by the paralel block structure. Simulation results are given to illustrate the performance of the proposed algorithm.

Recently, we proposed a low power consumption FIR switched-capacitor filter constructed with capacitors having capacitances in proportion to square roots of transfer function coefficient values. It is referred to as an FIR semi-parallel cyclic type (SPCT) filter. In this paper, we present IIR SPCT filter. It needs only a single operational amplifier, hence being low power consumption. The IIR SPCT filter has smaller total capacitance than one of the IIR parallel cyclic type (PCT) filter and better high frequency response than one of the IIR transfer function coefficient ratio (TCR) filter. As a whole, the IIR SPCT filter has middle performance of the IIR PCT and TCR filters for the total capacitance, the number of types of clock pulses, and high frequency response.

This paper proposes a new implementation of an adaptive noise canceller based upon a parallel block structure, which aims to raise the processing and convergence rates and to improve the steady-state performance. The procedure is as follows: First, an IIR bandpass filter with a variable center angular frequency using adaptive Q-factor control and two adaptive control signal generators are realized by the parallel block structure. Secondly, a new algorithm for adaptive Q-factor control with parallel block structure is proposed to improve the convergence characteristic. In addition, the steady-state performance of the filter is stabilized by using the variable step size parameter in adaptive control of the center frequency and the speed up of the convergence rate is achieved by adopting a normalized gradient algorithm for adaptive control. Finally, simulation results are given to demonstrate the convergence performance.

A method of designing digital FIR transmitter and receiver filter pairs for classes and partial response systems is presented. The truncated ideal impulse response of a specified class is used as an initial response of the filter pair in cascade. For class I filter, the impulse response has an even symmetry, then its transfer function is a linear phase lowpass function of case 1 or case 2. Therefore, the passband zeros occur in mirror image quadruplet (and doublet) and the stopband zeros occur on the unit circle. The initial stopband attenuation slopes gradually up as frequency increases. To get an equiripple stopband attenuation for both filters, the passband zeros inside and outside the unit circle are assigned to transmitter and receiver filters respectively, then the stopband zeros of each filter are redetermined. Both filters form a matched filter pair. Next, the passband zeros of the filter pair are adjusted to give minimum intersymbol interference (ISI) in the overall response. For class filter, the impulse response has an odd symmetry and its transfer function is a linear phase lowpass function of case 3. In this case, the filter pair are designed to have equiripple and nearly the same stopband attenuation. Zero ISI approximation is performed similarly. Two design examples are shown. One is a 57th order class I filter pair having 0.05% ISI. The other is 61st order transmitter and 57th order receiver class filter pair whose ISI is 0.2%.

Recently, we developed a low power consumption and small total capacitance switched-capacitor filter using a single operational amplifier. It is called a semi-parallel cyclic type (SPCT) filter, in which each capacitance is in proportion to the square root of a transfer function coefficient value. In this paper, we propose the SPCT filter using a single unity gain buffer (UGB). It will be referred to a UGB-SPCT filter. It is possible to use the UGB-SPCT filter over a wider frequency range than the SPCT filter since a UGB has nearly unity gain over a wide frequency range.

In this paper, a block implementation of high-speed IIR adaptive noise canceller is proposed. First, the block difference equation of an IIR filter is derived by the difference equation for high-speed signal processing. It is shown that the computational complexity for updating the coefficients of IIR adaptive filter can be reduced by using the relations between the elements of coefficient matrices of block difference equation. Secondly, the block implementation of IIR adaptive noise canceller is proposed in which the convergence rate is increased by successively adjusting filter Q-factors. Finally, the usefulness of proposed block implementation is verified by the computer simulations.

This paper describes a design technique of perfect reconstruction (PR) two-channel IIR filter bank. M.J.T. Smith et al., gave two types of PR IIR filter bank systems. One is the system such that the analysis and synthesis filters with nonlinear phase are implemented with all-pass polyphase filters and satisfy the power complementary condition approximately. The other is the system such that all the analysis and synthesis filters have liner phase responses and do not satisfy the power complementary condition. To improve coding performance, we propose a filter bank system such that all the analysis and synthesis filters have linear phase and satisfy the power complementary condition approximately.