This paper presents three types of prefiltering for FIR digital filters to decrease the number of multipliers required. The first type is based on cyclotomic polynomials. It can be applied to any types of band-selective filters. The second is a mirror-image quadratic polynomial to make a passband shaping. Both types of the prefilters are used with the interpolation technique, and this improves each primitive characteristic in terms of the sharp transition. In the prefilter-equalizer design approach, these prefilterings bring about the reduction of the number of multipliers required in hardware implementation. The prefiltering efficiency is demonstrated by a few examples.

A unified approach to the derivation of canonical single amplifier circuits capable of realizing second-order filters with finite transmission zeros is proposed. Application of the proposed approach leads to the known circuits, as well as some new ones. Design formulae for the new circuits are presented, and their salient features are pointed out. Finally, design examples are also presented.

A systematic synthesis is presented to realize any digital filter into a power-wave digital filter. After three canonical matrix representations are introduced, a set of key concepts which comprises cascade interconnection of digital two-ports, pole localization, and computability is presented for the canonical cascade synthesis of lossless digital two-ports. The synthesis procedure consists of global decomposision and local decomposition. The procedure is so general as to give a unified solution to arbitrary frequency responses realization, and is so useful as to find new circuit structures. The synthesized circuits are of robustness and modularity. An illustrative example is included.

Continuous-time MOSFET-capacitor filters have quite a serious problem, that is, MOS transistors' nonlinearity drastically reduces the filters' dynamic ranges. Czarnul proposed an MOS resistive circuit with high degree of linearity and solved this problem. The method, however, requires two capacitors for each integrator. Consequently, the chip area and manufacturing cost will increase. This paper proposes a new single capacitor integrator which can cancel the nonlinearity of transistors. The integrator is applied to a canonical continuous-time filter synthesis with high linearity. A total harmonic distortion less than 0.33% is obtained by SPICE analysis.

This paper describes a design method of linear phase recursive FIR digital filters. The basic structure consists of a transversal part cascaded with a cyclotomic resonator, which is characterized by cycotomic polynomials and has no multipliers. The digital filters implemented by this method require the short wordlength both for multiplier coefficients and for signals in their transversal part. By introducing integer arithmetic, the filtering operation proceeds fast and exactly. As a bonus, it is possible to employ a multiplier-less implementation in most practical applications. While the stability of this type of structure requires an integer-valued impulse response, a satisfactory procedure assures the requirement. A parameter to control the approximation error is found somewhat predictively rather than tentatively.

Analog signal processing is important for the following reasons. There exist many analog environments, and integrated analog circuits have several advantages over digital circuits. On the other hand, a digital approach can provide another features, such as accurate operation and programmability. Therefore, both circuits are effectively combined, resulting in high performance LSIs. This tutorial paper provides an overview for the recent and future trends in design and applications of integrated analog signal processing circuits. First, design techniques are reviewed for operational amplifier (Op-Amp), monolithic bipolar active RC circuits, switched-capacitor (SC) circuits, continuous-time MOS circuits, and analog-to-digital converter (ADC). High frequency filter realization, up to 100 MHz, has been tried by bipolar active RC circuits and GaAs circuits. Improved design techniques for SC circuits have been proposed. They include noise cancellation and building blocks with reduced sensitivity to nonideal Op-Amp performance. In order to overcome some SC circuit drawbacks due to a sampled data circuit, continuous-time MOS circuits have been proposed. Successful results have been obtained by using an automatic tuning method. A multi-stage noise shaping ADC is very useful to integrate an accurate ADC. A high signal-to-noise ratio (SNR), more than 91 dB, was obtained by the three-stage ADC, which can be applied to digital audio system. Automatic design and fabrication processes are also important aspects. Silicon compilers for SC circuits are overviewed. Systematic design rule, by which a globally optimum solution can be obtained, requires further investigation. A mixed analog/digital master slice LSI has been proposed to simplify an LSI customizing process. A voice-band MODEM LSI has been developed, resulting in good filter responses and SNR. Finally, promising applications of integrated analog circuits are briefly reviewed. Analog circuits are superior to a digital version in operating speed, power dissipation and integration density. In actuality, however, both approaches will be combined, resulting in mixed analog/digital LSIs where both circuits supplement each other's excellent features and negate drawbacks.

Continuous-time high-frequency active filters suitable for monolithic implementation by standard low cost bipolar process are presented. Balanced NIC's are used to cancel out the loss of passive RC integrators, thus realizing active loss-less integrators with good high-frequency performance. Two types of balanced integrators are proposed and their quality factors are analyzed. The proposed NIC-integrators are used to realize tunable active filters capable of low-voltage operation and without the drawbacks of the NIC-gyrator filters. As an example of application of the NIC-integrators to leapfrog simulation of RLC ladders a second-order 1 MHz bandpass filter was designed, computer simulated and laboratory tested showing good results.

The 1950's was important period for Japanese electronic industry. It embarked in a new enterprise after the defeat of Japan in the World War. Dr. Masamitsu Kawakami of the Tokyo Institute of Technology made a great contribution to the leveling up of the people involved in electronics through his books "Denshikairo I-V". In this paper, activity of Dr. Kawakami in the field of active networks before and during the 1950's are introduced. It includes realization of negative and higher order impedances and the development of the theory of elementary active 2-ports. His works were inherited by the successors including the author. The development of a current inversion negative impedance converter, and its application to active network synthesis is reflected. The influence of these works on the research in the later age is also shown.

A direct procedure to realize pipelinable low-sensitivity digital filters is developed only in the z-domain. It is possible to realize arbitrary digital transfer functions using this procedure. The key concept for the low-sensitivity property lies both in the matching concept in doubly-terminated lossless networks and in the localization of transmission zeros. The synthesis procedure is based on successive extractions of transmission zeros by means of lossless but not always reciprocal transfer scattering matrices. Since a transfer scattering matrix involves the transmission zeros as its poles, such a matrix is suitable for their localization. Furthermore a universal first/second-degree section is derived explicitly.

Digital Signal Processors with complex arithmetic capability (DSP-C) are useful for various applications. In this paper, we propose a method for the effective implementation of specific circuits with real coefficients on DSP-C. DSP-C has special hardware such as a complex multiplier so that a complex calculation can be performed with only one instruction. First, we show that nodes with two real coefficient input branches can be implemented by complex multiplications. We apply this implementation to 2D circuits and transversal circuits with real coefficients. Next, we introduce a new computational mode (Advanced mode) and a new multiplier into PSI, a kind of DSP-C which has been proposed already, in order to process the circuits effectively. The effectiveness of the proposed method is shown by simulation in the last part.

An integrator is quite a suitable active element for high-speed filters. The effect of its excess phase shifts, however, is severe in the case of high-Q filter realization. The deterioration due to the excess phase shifts cannot be avoided when only integrators are used as frequency-dependent elements like in leapfrog realization. This paper describes a design of second-order high-speed and high-Q filters with low sensitivity to excess phase shifts of integrators by adding a passive RC circuit. The proposed method can drastically reduce the effect due to the undesirable pole of an integrator, which is the cause of the excess phase shifts, compared to conventional filters using only integrators. As an example, a fourth-order bandpass filter with 5-MHz center frequency and Q=25 is implemented by the proposed method on a monolithic chip. The results obtained here show quite good agreement with the theoretical values. This demonstrates effectiveness of the proposed method and feasibility of high-speed and high-Q filters on a monolithic chip.

A systematic method for synthesizing multi-port networks specified by scattering matrices is proposed. First, a basic circuit for converting the port parameters is introduced. At each port the basic circuit converts the voltage and the current into the incident and the reflected wave quantities. Then each element of the scattering matrix is realized using the conventional techniques for the realization of one-input one-output transfer functions. When all the elements of the scattering matrix are either positive constant or zero, the resultant network can be simplified. With the proposed method, some known structures can be obtained very easily and two new structures for hybrid networks are derived. One of the salient feature of the proposed method is that it also provides the physical interpretation of structures derived. Experimental results are also given.

Electronic circuits operating from low-voltage power supplies are required in battery operated equipments and in monolithic ICs realized using high-frequency high-density integrated circuit technology. High-frequency active filters that are suited for monolithic implementation using integrators based on negative impedance converters (NICs) have been presented in the literature. In this paper a low-voltage NIC-integrator is presented along with some applications to high-order high-frequency active filters. Methods to compensate the losses of integrators suitable for high-frequency low-power applications are introduced. Realizations of high-order filters with transmission zeros without floating capacitors or additional summers are also presented. Experimental and simulation results are shown to confirm the validity of the proposed circuits.

An iterative design of constrained recursive digital filters is developed. The designing scheme requires no initial values. The constraints are subjected to degrees of both numerator and denominator, transmission zeros and poles, if any, and passband and stopband shaping. The resulting filter completes a prescribed magnitude of either passband or stopband ripples. The optimality property of the filters is examined in detail with emphasis on specifications. The designing scheme involves the elliptic design as a special case. Illustrative examples are also given.

Based on the cyclotomic polynomials, this paper describes a family of efficient and practical interpolators for interpolated FIR filters. The family can be applied to bandpass filters as well as lowpass/highpass filters without any multiplications. It also mitigates the inconvenience to select a practical interpolation factor, and gains a further saving in computational complexity required. Several examples are given to demonstrate the effectiveness for reducing the computational complexity required.