The paper describes a digital circuit technique to process directly bit-stream signals from sigmadelta modulation based analogue-to-digital converters and the application of the technique to communication systems. The newly developed adder and multiplier are fundamental processing circuit modules. Using the fundamental modules and up/down counters, other circuit modules, such as oscillators, dividers and square root circuits, can also be realised. Signal processors built from the modules have three advantages over multi-bit Nyquist rate processors. First, single-bit/ multibit converters are not needed at the inputs of the processors because the arithmetic modules directly process the bit-stream signals. Secondly, the physical areas for routing the signals among the circuit modules are small since they are in the form of a bit-stream. Thirdly, the processors are built from a smaller number of logic gates than conventional Nyquist rate processors because of the simple structure of the circuit modules. As an application of the technique to digital signal processing for communications, a QPSK demodulator is presented. In addition to circuit simulations of the demodulator, a useful linear analysis to estimate the influence of the noise components contained in the outputs from the circuit modules on the steady-state demodulation performance is explained.
We construct arithmetic modules for signal processing with sigma-delta modulated signal form which has advantage in signal quality over other pulsed signal forms. In the first part of this paper, adders and exponential function modules are presented first and secondly. By utilizing the two modules, several transcendental functions including hyperbolic and logarithmic functions are constructed. The exponential functions and logarithmic functions provide log-domain arithmetic operations including multiplication, division, and power functions. Only two bit-manipulations, bit-permutation with sorting networks and bit-reversal with NOT gates, have built up all the arithmetic operations on any form of sigma-delta modulated signals. These modules, together with algebraic functions to be presented in the second part of this paper, organize an extensive module library for the sigma-delta domain signal processing.
Electrons possess both wave and particle natures. In this paper, we represent an electron on multi-stage coupled electron waveguides both by a wave function and by a probabilistic particle. We show first that time evolution of the wave function can be obtained by the combined use of the tight-binding method and two-port circuit theory. The wave function is in variable-separable form when wave propagation on the coupled electron waveguides is single mode. We present secondly that the variable separation simplifies the general Langevin equation describing behavior of the probabilistic particle. According to these two schemes, wave functions and sample particle trajectories on single and two-stage coupled electron waveguides were exemplified.
We propose simplc arithmetic circuits which directly add and multiply delta-sigma modulated single-bit signals without converting into multi-bit signals. Theoretical analysis and the circuit simulations show that the output noise is lower at low frequency. The ratio of maximum signal power to total noise power in the frequency band from DC to 1/32 ofsampling frequency is over 30dB.Any linear and nonlinear signal processing system will be practically built up using the arithmetic circuits and up/down counters integrating the singlebit signals. The application systems will be implemented in small LSI dice since both the simple arithmetic circuits and the single-bit signal routing require small physical areas. In this paper a synchronizaton loop is given as an application of the proposcd circuits.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.