Signal Flow Diagrams Research Articles

Radix-22 Algorithm for the Odd New Mersenne Number Transform (ONMNT)

This paper introduces a new derivation of the radix-22 fast algorithm for the forward odd new Mersenne number transform (ONMNT) and the inverse odd new Mersenne number transform (IONMNT). This involves introducing new equations and functions in finite fields, bringing particular challenges unlike those in other fields. The radix-22 algorithm combines the benefits of the reduced number of operations of the radix-4 algorithm and the simple butterfly structure of the radix-2 algorithm, making it suitable for various applications such as lightweight ciphers, authenticated encryption, hash functions, signal processing, and convolution calculations. The multidimensional linear index mapping technique is the conventional method used to derive the radix-22 algorithm. However, this method does not provide clear insights into the underlying structure and flexibility of the radix-22 approach. This paper addresses this limitation and proposes a derivation based on bit-unscrambling techniques, which reverse the ordering of the output sequence, resulting in efficient calculations with fewer operations. Butterfly and signal flow diagrams are also presented to illustrate the structure of the fast algorithm for both ONMNT and IONMNT. The proposed method should pave the way for efficient and flexible implementation of ONMNT and IONMNT in applications such as lightweight ciphers and signal processing. The algorithm has been implemented in C and is validated with an example.

A Tunable Leapfrog Complex Filter for High Frequency and Wide Bandwidth Using Multi-Output Current Differencing Transconductance Amplifiers

ABSTRACTIn this paper, a new fourth-order complex (polyphase) filter is realized with the leapfrog structure. The proposed filter is based on the first-order stage using multi-output current differencing transconductance amplifiers (MOCDTAs). The design procedures for the realization of the first-order stage and fourth-order leapfrog polyphase filter are presented. In the procedures, the signal flow diagrams are also presented. The proposed design using MOCDTA simplifies the circuit of the current-mode leapfrog complex filter, where there are no resistors and with minimum number of active components. Besides, its centre frequency and bandwidth could be electrically tunable independently. The centre frequency of the proposed filter could be adjusted from 20 to 80 MHz, and its bandwidth could be more than 20 MHz. With ± 1.25 V supply, two examples of the proposed filter are introduced. Their bandwidths are from 46.1 to 68.5 MHz and from 22.3 to 48.4 MHz, respectively. Their image rejection ratios could be more than 59 and 39 dB, respectively. Meanwhile, both the IIP3s are over 18 dBm. The theoretical results are demonstrated by using SPECTRE simulation in CHRT 0.18 μm standard complementary metal oxide semiconductor (CMOS) process.

The Calculus of Signal Flow Diagrams I: Linear relations on streams

We introduce a graphical syntax for signal flow diagrams based on the language of symmetric monoidal categories. Using universal categorical constructions, we provide a stream semantics and a sound and complete axiomatisation.A certain class of diagrams captures the orthodox notion of signal flow graph used in control theory; we show that any diagram of our syntax can be realised, via rewriting in the equational theory, as a signal flow graph.

Model Construction for Butanol Fermentations with Acetate/Butyrate Added by Graph Theory

Acetate /butyrate metabolic pathways play an important role in ABE fermentation and their changes will influence entire carbon fluxes distribution. Several fermentations with intermittent feeding of acetate / butyrate were conducted in a 7 L fermentor and the results indicated that exogenous acetate / butyrate enhanced solvents productivities by 47. 1% and 39. 2% respectively,and butanol / acetone ratios were improved by 21. 7% for butyrate added batch and decreased by 16. 2% for acetate added batch. A nonlinear constraint was utilized for acids rates calculation and the results revealed that acetate / butyrate formation pathways were almost blocked by corresponding acids feeding. Then a metabolic model constructed by graph theory was utilized to dispose those cases with acetate / butyrate added and to predict solvents production,in which some improvements were adopted based on the calculation results and related references. The model predicted solvents production, butanol / acetone ratios accurately and constructed the directed signal flow diagrams of ABE network under different conditions correctly.

Calculation of scattering parameters in multiple-interface transmission-line transducers

Transmission-line scattering parameters becomes unpractical to calculate as one includes more interfaces. Thus, to get an analytical expression, approximations are required. In this paper, an approximation methodology for the calculation of scattering parameters of transmission-line transducers is presented. The transducer cell is partitioned at each interface and the partial scattering equations are calculated, considering two interfaces at a time. Next, standard techniques are applied to solve the signal-flow diagrams to obtain the full scattering equations. Transmission-line transducers are used for the measurement of power absorption and reflection of different materials, such as: liquids, granular medium, and ground, in the RF/microwave range. Such measurements are used to extract materials properties. The proposed methodology has been applied to a coaxial transducer cell filled with different low-loss liquids. The results have been validated with computer simulations and experimental measurements. Measurements and simulations were carried out in the 300kHz to 3GHz frequency range.

The problem with time in mixed continuous/discrete time modelling

The design of cyber-physical systems requires the use of mixed continuous time and discrete time models. Current modelling tools have problems with time transformations (such as a time delay) or multi-rate systems. We will present a novel approach that implements signals as functions of time, directly corresponding to their mathematical representation. This enables an exact implementation of time transformations and as an additional advantage enables local control over time. A representation of components and signals in both domains is provided, together with composition operators to allow the specification of signal flow diagrams.

Putting the “Control” in Metabolic Control Analysis

Metabolic control analysis is a framework for characterizing the parametric sensitivity of metabolic pathways and genetic networks. We establish a connection between metabolic control analysis and control theory. The main result is that we can use classical control theory and the associated signal-flow (block) diagrams to analyze biochemical reaction networks and that many results in metabolic control analysis have direct counterparts in control In the process, we illustrate how some problems in biochemical network analysis can be reformulated in a control-theoretic framework.

Systems approach to sound in porous media

A method based on linear systems analysis is developed for estimating propagation characteristics of sound in porous media both in the fluid of the pores and in the elastic structural frame. It predicts propagation constants, pressure ratios, and velocity ratios in close agreement with previous work. The two coupled systems are visualized in the form of signal flow diagrams that are composed of transfer admittances and transfer impedances.

APGAN and RPMC: Complementary Heuristics for Translating DSP Block Diagrams into Efficient Software Implementations

Dataflow has proven to be an attractive computational model for graphical DSP design environments that support the automatic conversion of hierarchical signal flow diagrams into implementations on programmable processors. The synchronous dataflow (SDF) model is particularly well-suited to dataflow-based graphical programming because its restricted semantics offer strong formal properties and significant compile-time predictability, while capturing the behavior of a large class of important signal processing applications. When synthesizing software for embedded signal processing applications, critical constraints arise due to the limited amounts of memory. In this paper, we propose a solution to the problem of jointly optimizing the code and data size when converting SDF programs into software implementations. We consider two approaches. The first is a customization to acyclic graphs of a bottom-up technique, called pairwise grouping of adjacent nodes (PGAN), that was proposed earlier for general SDF graphs. We show that our customization to acyclic graphs significantly reduces the complexity of the general PGAN algorithm, and we present a formal study of our modified PGAN technique that rigorously establishes its optimality for a certain class of applications. The second approach that we consider is a top-down technique, based on a generalized minimum-cut operation, that was introduced recently in [14]. We present the results of an extensive experimental investigation on the performance of our modified PGAN technique and the top-down approach and on the trade-offs between them. Based on these results, we conclude that these two techniques complement each other, and thus, they should both be incorporated into SDF-based software implementation environments in which the minimization of memory requirements is important. We have implemented these algorithms in the Ptolemy software environment [5] at UC Berkeley.

A Low-Power Wide-Linear-Range Transconductance Amplifier

The linear range of approximately ±75 mV of traditional subthreshold transconductance amplifiers is too small for certain applications—for example, for filters in electronic cochleas, where it is desirable to handle loud sounds without distortion and to have a large dynamic range. We describe a transconductance amplifier designed for low-power (< 1 µW) subthreshold operation with a wide input linear range. We obtain wide linear range by widening the tanh, or decreasing the ratio of transconductance to bias current, by a combination of four techniques. First, the well terminals of the input differential-pair transistors are used as the amplifier inputs. Then, feedback techniques known as source degeneration (a common technique) and gate degeneration (a new technique) provide further improvements. Finally, a novel bump-linearization technique extends the linear range even further. We present signal-flow diagrams for speedy analysis of such circuit techniques. Our transconductance reduction is achieved in a compact 13-transistor circuit without degrading other characteristics such as dc-input operating range. In a standard 2 µm process, we were able to obtain a linear range of ±1.7V. Using our wide-linear-range amplifier and a capacitor, we construct a follower–integrator with an experimental dynamic range of 65 dB. We show that, if the amplifier‘s noise is predominantly thermal, then an increase in its linear range increases the follower–integrator‘s dynamic range. If the amplifier‘s noise is predominantly 1/f, then an increase in its linear range has no effect on the follower–integrator‘s dynamic range. To preserve follower–integrator bandwidth, power consumption increases proportionately with an increase in the amplifier‘s linear range. We also present data for changes in the subthreshold exponential parameter with current level and with gate-to-bulk voltage that should be of interest to all low-power designers. We have described the use of our amplifier in a silicon cochlea [1, 2].

Signalfluß-Bilder als Hilfsmittel bei der Beschreibung hypnotischer Trancezustände

A model is developed to show the formation of the hypnotic trance states. As experimental results are rare in this field the development of the model is mainly done by assuming possible and practicable connections. It is the beginning of cybernetic models for this domain and may encourage further work in this direction. The focal point is the separation of energy-flow from information-flow. Only the latter is needed with the arrangement of signal-flow diagrams. These diagrams show that the different trance states may be explained as different information-processing systems. We dont require the physiological background as we have transformed the problem into a pure psychology-problem -- On this way we find two switch-over systems: One that opens the loop between the model of outer world and the inner decision system. By this way it gives to the other system the possibility to follow word-for-word the suggestions, given by the hypnotist.

An efficient tearing algorithm based on minimum sum of weights

A simple but efficient tearing algorithm for decomposition of chemical process flowsheets is described. It does not involve the use of signal flow diagrams or manipulation of any matrices. All the streams are assigned definite weights and the cut-set of tear streams is found by minimizing the sum of weights. The algorithm is equally efficient when arbitrary weights are assigned.

A unified derivation and critical review of modal approaches to model reduction

Six of the most commonly-used modal reduction techniques are represented by means of signal flow diagrams connecting inputs and state variables. In this representation, the derivation and the cross-comparison of the various methods are greatly facilitated. Each method is then analysed to determine key characteristics, i.e. (i) steady-state agreement, (ii) initial-value agreement, (iii) independence of the reduced model on the choice of retained state variables and inputs, and (iv) eigen vector orientation. Realistic, large-scale systems are used to evaluate the static and dynamic characteristics of each model reduction method numerically. These studies reveal some important, and often unrecognized, weaknesses of several traditional techniques and confirm the strength of the newly-developed technique of Litz.

The measurement of local velocity of solid particles

Methods for measuring the local solid-particle velocity inside equipment for very high solid loadings are reviewed, and the underlying principles of these methods are discussed in terms of their signal flow diagrams. The fiber optic method as well as a low cost correlator developed by the present authors for use in signal processing are discussed in detail. The choice of any specific measuring method for maximum efficiency is contingent upon its characteristics and the given flow systems. However, the use of the correlation method in conjunction with a fiber optic probe appears to be a promising and simple approach because of the availability of low cost signal processing devices.

Saturn launch vehicle's navigation guidance, and control system

The navigation, guidance and control system of Saturn launch vehicles is reviewed with respect to systems engineering; operational requirements and design aspects determine the synthesis and the implementation of the system, which must fulfill extreme reliability demands. The iterative path adaptive guidance mode, featuring flight path optimization, is presented in its computational form. The launch vehicle dynamics for attitude control cover the rigid-body behavior and the body-bending characteristics of the vehicle as well as the sloshing behavior of the propellants, from which the vehicle control functions are derived. Signal flow diagrams, computational arrangements and specific components such as the inertial measurement unit demonstrate the implementation of the navigation, guidance and control system. Flight simulation has been applied for the design, analysis and verification of the navigation, guidance and control system. The evaluation of the flight results exhibits the excellent overall performance of the system even under unusual flight perturbations.

Description and Performance of the Saturn Launch Vehicle's Navigation, Guidance, and Control System

A review of the navigation, guidance, and control system of the Saturn launch vehicle includes the system analysis and design, signal flow diagrams, redundancy, and self-checking features used to obtain extreme reliability for crew safety.The iterative path adaptive guidance mode, featuring flight path optimization, is explained and presented in its computational form. Following the analytical considerations, the main guidance and control components are described. The navigation and control information is obtained inertinlly by a gyro-servo-stabilized, three-gimbal platform system with three mutually orthogonal pendulous-integrating gyro accelerometers; the single-degree-of-freedom gyros as well as the accelerometers use externally-pressurized gas bearings. Rate gyroscopes provide attitude staoilization; some vehicle configurations require additional accelerometer control to reduce wind loads. The digital computer system serves as the computation, central data, and onboard programing center, which ties in with the ground computer system during the prelaunch checkout of the overall system. The control signals are combined, shaped, attenuated, and amplified by an analog type control computer for engine actuator control.Results obtained in recent launchings of Saturn V vehicles are presented to confirm the adequacy of the navigation, guidance, and control system and its overall performance even under extreme flight perturbations.

New angle on ultrasonic cleaning: Metalworking Production (31st January 1968) p50

Transmission-line scattering parameters becomes unpractical to calculate as one includes more interfaces. Thus, to get an analytical expression, approximations are required. In this paper, an approximation methodology for the calculation of scattering parameters of transmission-line transducers is presented. The transducer cell is partitioned at each interface and the partial scattering equations are calculated, considering two interfaces at a time. Next, standard techniques are applied to solve the signal-flow diagrams to obtain the full scattering equations. Transmission-line transducers are used for the measurement of power absorption and reflection of different materials, such as: liquids, granular medium, and ground, in the RF/microwave range. Such measurements are used to extract materials properties. The proposed methodology has been applied to a coaxial transducer cell filled with different low-loss liquids. The results have been validated with computer simulations and experimental measurements. Measurements and simulations were carried out in the 300 kHz to 3 GHz frequency range.

Ultrasonics for Industry exhibition: Wire Industry, Vol 34, No 408 (December 1967) p1268

Transmission-line scattering parameters becomes unpractical to calculate as one includes more interfaces. Thus, to get an analytical expression, approximations are required. In this paper, an approximation methodology for the calculation of scattering parameters of transmission-line transducers is presented. The transducer cell is partitioned at each interface and the partial scattering equations are calculated, considering two interfaces at a time. Next, standard techniques are applied to solve the signal-flow diagrams to obtain the full scattering equations. Transmission-line transducers are used for the measurement of power absorption and reflection of different materials, such as: liquids, granular medium, and ground, in the RF/microwave range. Such measurements are used to extract materials properties. The proposed methodology has been applied to a coaxial transducer cell filled with different low-loss liquids. The results have been validated with computer simulations and experimental measurements. Measurements and simulations were carried out in the 300 kHz to 3 GHz frequency range.

The effect of dry and fluid lubrication on instrument, ball-bearing torques at high speed : H. H. Mabie, Lubrication Eng., 21 (6) (1965) 242–249; 21 figs., 1 table

A review of the navigation, guidance, and control system of the Saturn launch vehicle includes the system analysis and design, signal flow diagrams, redundancy, and self-checking features used to obtain extreme reliability for crew safety.The iterative path adaptive guidance mode, featuring flight path optimization, is explained and presented in its computational form. Following the analytical considerations, the main guidance and control components are described. The navigation and control information is obtained inertinlly by a gyro-servo-stabilized, three-gimbal platform system with three mutually orthogonal pendulous-integrating gyro accelerometers; the single-degree-of-freedom gyros as well as the accelerometers use externally-pressurized gas bearings. Rate gyroscopes provide attitude staoilization; some vehicle configurations require additional accelerometer control to reduce wind loads. The digital computer system serves as the computation, central data, and onboard programing center, which ties in with the ground computer system during the prelaunch checkout of the overall system. The control signals are combined, shaped, attenuated, and amplified by an analog type control computer for engine actuator control.Results obtained in recent launchings of Saturn V vehicles are presented to confirm the adequacy of the navigation, guidance, and control system and its overall performance even under extreme flight perturbations.

A rational approach to sound system planning

The importance of basic planning for sound amplification and reinforcement systems is discussed. The first step in basic planning is to determine the functions of the sound system by a study of the building and use for the system. A list of objectives or requirements will serve as the basis for sound system planning and can be interpreted by signal flow diagrams. These can then serve as the basis for the more detailed functional diagrams or wiring diagrams of the sound system. After determining the functional of the system, the designer proceeds with the acoustical and architectural planning. A basic decision is the choice of either a central or a distributed loudspeaker system. This is followed by a determination of the location and orientation of microphones and loudspeakers and the selection of the actual transducers required for the job. Finally, control and amplification equipment are selected. Basic planning is presented as a portion of the overall effort that includes the detailed electronic design of the system, a specification if one is required, careful installation, and final adjustments.