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This paper develops techniques to synthesize any transfer admittance or voltage transfer function specification with a prescribed load. The methods are illustrated by examples.
Considerable work has been done over the past two decades in the field of active network theory. The advent of integrated circuits and the quest for miniaturization have set the real pace in the realm of active network synthesis. The various active elements that have been used are negative impedance converters (NIC), tunnel diodes, gyrators, finite and infinite gain amplifiers, etc. In general the realization of an open-circuit voltage transfer function is an important problem and many ingenious techniques (Yanagisawa 1957, Mitra 1968, Natarajan and Murti, 1969 a, b, Rao 1969, Rao and Raghava Rao 1971) have been developed since the birth of active network synthesis. [ABSTRACT FROM AUTHOR]

A system for encoding and storing a program of stimuli on magnetic tape is described. The system uses tones of different frequency recorded on magnetic tape as the code. The decoder is a frequency selective integrated circuit capable of recognizing a wide range of frequencies. A number of these devices may be combined in parallel to decode tones signaling different contingencies to the subjects. The device may be readily interfaced with integrated circuit logic to generate the stimuli and process behavioral responses. [ABSTRACT FROM AUTHOR]

The article presents information on recent progresses made in the field of miniaturized biotelemetry. Transistor packages for thin-film circuits are now made by many companies. It is stated that thin-film active device research has progressed to such a stage that the time for practical usage is almost at hand. Companies are making custom-designed, integrated solid circuits at a cost roughly 20 to 50% higher than the equivalent thin-film circuit. There is easy commercial availability of thin-film circuits used in miniaturized biotelemetry design. The cost of custom-designed thin-film circuits has also come down.

Physiological amplifier-recorders often are bulky and difficult to interface with the programming equipment used in cardiovascular conditioning studies. Two amplifiers are described which are small, easily constructed, portable, and interface easily with programming equipment. The amplifiers are constructed from integrated circuit operational amplifiers. A filter is also described which removes 60 Hz interference and attenuates movement artifacts and respiration fluctuations in the output signals of the amplifiers. Two amplifier circuits are described, one for electrocardiogram signals and one for photoplethysmogram signals. Used separately or in combination, these amplifiers can be employed to investigate the conditioning (or functioning) of beat-to-beat heart rate, blood pressure, or particular components or frequencies of the electrocardiogram and photoplethysmogram waves. [ABSTRACT FROM AUTHOR]

The realization of quadratic transfer functions by an active band-pass filter is described. The hybrid-integrated circuit used consists of a three-terminal passive network, connected to a high-gain inverting amplifier. A design procedure for minimizing the gain-sensitivity product is given. By interchanging two connections between the passive network and the amplifier, the band-pass is converted into a band-stop characteristic. A pair of such circuits may be cascaded to generate a generalized biquadratic transfer function. Parasitic singularities due to each circuit are eliminated through pole-zero cancellation between the cascaded filters. In this manner, a wide range of transfer functions is realizable. A low-pass or a notch filter can be obtained by adding an isolating stage. [ABSTRACT FROM AUTHOR]

A novel method of digit shifting in a bidirectional shift register is described which provides substantial saving of components in terms of gates. In this method only the bits occupying the 1-position of the 8-4-2-1 code can shift in either direction. Bits of the same digit position are then made to change place among themselves. Eight clock pulses are required to shift the bits through one digit position, but the number of clock pulse requirement is independent of the number of digits involved in the shifting process. However, this shortcoming of speed reduction can be overcome by providing a separate clock for this purpose which may be several times faster than the system clock. The drastic reduction in component count and cost of the new method over the conventional one has also been illustrated. These together with the reduction of interconnecting leads and power dissipation leads to the possibility of fabricating multidigit bidirectional shift, registers in monolithic integrated circuit packages. [ABSTRACT FROM AUTHOR]

By considering the current rather than the voltage differential equation, the parameters of the multilayer C-R-NC distributed network with an exponential inhomogeneity are derived. The structure is thought to be as important in the characterization of integrated circuits as the better known R-C-NR, and the nature of their duality is explained. Frequency responses are evaluated and design curves presented for single-element notch filters. Finally, a recently developed numerical inversion technique is applied to the evaluation of the transient responses of these networks. [ABSTRACT FROM AUTHOR]

The Lang x-ray diffraction technique provides a simple non-destructive method for measuring flexure in single-crystal silicon wafers at different stages of integrated circuit fabrication. A molybdenum target provides K and K x-radiation which is diffracted from the set of {110} normal to the surface parallel {111}. The widths of the diffracting regions and their separation are simply related to the flexure, which may be expressed as a radius of curvature (). This method is limited to wafers which do not diffract from the entire region irradiated, i.e. < 1590 in. for a 1 in. diameter wafer. Results indicate a change in the radius of curvature from > 1590 in. for a substrate to 202 in. after several processing stages, Non-uniformity in individual wafers is much greater after the material has been through several processing stages. [ABSTRACT FROM AUTHOR]