Digital signal

About: Digital signal is a research topic. Over the lifetime, 44213 publications have been published within this topic receiving 345279 citations.

Suppression of parasitic oscillations in wave digital filters

Abstract: Parasitic oscillations can occur in digital filters due to the granularity of the signal and to overflow. It is shown that for wave digital filters, the earlier concept of pseudopower leads to a function called stored pseudopower, from which a simple criterion guaranteeing absence of parasitic oscillations can be derived. For fixed-point two's-complement arithmetic, this criterion can be taken into account by particularly simple requirements for the adaptor output signals. A special type of calculus is developed which makes it possible to derive the corresponding simple requirements for the chopping operations at the various stages of the signal processing in the adaptors. The method is extended to cover scaling.

State of charge indicator

Abstract: A method and apparatus for producing a visual signal of the state of charge of a battery selectively connected and disconnected from an external load. A test load is connected to the battery for a predetermined period of time to draw a current pulse from the battery when the battery is disconnected from the external load. Simultaneously, the voltage of the battery is measured. The measured voltage is converted to a digital signal, and the digital signal is transmitted to a storage means. The stored signal is then transmitted to a visual display device.

Real-Time Granular Synthesis with a Digital Signal Processor

Abstract: Following earlier models by Gabor (1947) and Xenakis (1971), Curtis Roads (1978, 1985) has proposed granular synthesis as a unique method of achieving complex sounds by the generation of high densities of small grains on the order of magnitude of 10-20 msec duration. He has also used the technique in his composition prototype (1975) and as a component of several other tape pieces. The complexity of calculation involved has in the past necessitated a non-real-time approach involving a general-purpose computer music system. As a result, few composers have worked with the technique or heard the range of sounds it produces. Current digital signal processing (DSP) hardware offers the potential for real-time implementation of this technique by dividing the responsibility for calculation between the DSP and various levels of

Real time correction of a digital pwm amplifier

Abstract: Distortion and noise in high power digital PWM amplifiers is reduced by measuring the difference between the desired output signal and the actual output signal on a pulse by pulse basis. This analog error is converted into a digital signal with an analog to digital converter (ADC). The digital error signal is then used to correct the feedback of the delta sigma modulator in real time. Preferably, more than one moment of the modulator signal is corrected via the feedback. Preferably, the predictable error of the circuitry which is known a priori is also corrected by correcting the delta sigma modulator feedback. A specialized ADC allows the loop delay to be low, without compromising accuracy.

Accurate measurement of power system frequency using a digital signal processing technique

Abstract: This paper describes the design, computational aspects, and implementation of a digital signal processing technique for measuring the operating frequency of a power system. The technique provides correct and noise-free estimates for near-nominal, nominal, and off-nominal frequencies in about 25 ms, and it requires modest computations. The proposed technique is implemented using a DSP-based board and has been extensively tested using voltage signals obtained from a dynamic frequency source and from a power system. Some test results are presented in the paper.