Digital signal

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

Microprocessors and Digital IC's for Motion Control

Abstract: This paper reviews the recent developments in microprocessors and digital IC’s with a special attention to applications to motion control area. First, the use of microprocessors and digital IC’s in the control of electrical motor drives is considered. General-purpose microprocessors and microcontror‘lers are then presented with emphasis on features that are necessary *for the implementation of real-time control systems. High-pegormance advanced processors such as digital signal proces Tors (LISP’s), reduced-instruction-set computing (RISC) processors, and parallel processors are studied. Development and debugging tools required for developing sophisticated microprocessor-based control systems are considered. The capabilities of application-spec$c integrated circuits (ASIC’s) in motion control and their design process are examined. Typical application examples illustrating recent research works in digital motion control using microprocessors and digital IC’s are presented. The potentials of new devices are cmsidered for application to high-pegormanre drive systems. Trends for future development of the microprocessor technology for motion control applications are projected.

Control device for telephone station and acoustic headset usable in said telephone station

Abstract: A control device (4) for connection of a telephone set (2) to at least one speaker (41) for reception of an audio signal and/or of at least one microphone (46) for transmission of an audio signal, comprising a digital signal processor (DSP) (10), an analog-to-digital converter (ADC) (11) to convert the digital signal coming from the telephone set (2) and/or from the microphone (46) to a digital signal that can be processed by the DSP (10), and a digital-to-analog converter (12) to convert the digital signal coming from the DSP (10) to an analog signal to be sent to the telephone set (2) and/or to the speaker (41), the control device (4) performing different functions, such as recognition of the voice conductors, storage and transmission of messages, equalization of the signal received and suppression of ambient noise.

Linearized digital thermometer

Abstract: A digital thermometer uses a microprocessor computer containing stored information relating to the response characteristics of a transducer to supply a measurement of temperature. The transducer is preferably a thermistor whose resistance varies in a predetermined and nonlinear relation to its temperature. The microprocessor computer includes a read-only memory which has been preprogrammed with piece-wise linearized information approximating the nonlinear relation of resistance and temperature of the thermistor. A current source develops a voltage across the thermistor which is related to the temperature of the thermistor. The voltage across the thermistor is converted into a digital signal, and the digital signal is related to the piece-wise linearized information stored. The temperature equivalent is calculated from a first order algebraic equation determined by the relationship of the digital signal to the stored information.

Delta-sigma a/d converter

Abstract: A delta-sigma modulator (196) comprising a first quantizer (202) providing a first digital signal d0(k) representing the input signal g(t); a loop filter (198) with input signal paths (200); a loop quantizer (160) providing a corrective digital signal d1(k) representing the loop filter's (198) output signal y(t); an array of feedback DACs (162) D/A converting the sum d(k) = df(k) = d0(k) + d1(k) of the first and the corrective digital signals and injecting feedback signals into the loop filter (198) The loop filter's (198) input note (164) is applied the difference of the input signal g(t) and the global analog feedback signal a3(t) The global feedback signal a3(t) is delayed several clock cycles with respect to the digital output signal d(k) The delay is used to carry out mismatch-shaping and deglitching algorithms in the feedback DACs (162) The feedback DACs' (162) different delays and gain coefficients are designed such that the modulator (196) is stable The filter's input signal paths (200) and the compensating DAC (204) are designed such that the gain from the input signal g(t) to the loop quantizer (160) is small, ideally zero Thus, the loop quantizer's (160) resolving range can be a fraction of the first quantizer's (202) resolving range, whereby the output signal's d(k) resolution can be much higher than the individual resolutions of d0(k) and d1(k) The delta-sigma modulator (196) is well suited for the implementation of high-resolution wide-bandwidth A/D converters Important applications include digital communication systems

Digital sound broadcasting using a dedicated control channel

Abstract: A method and apparatus for transmitting digital sound are disclosed. The method contemplates transmitting a digital radio signal (such as an FM band signal) over a plurality of sub-channels (43) subject to some constraints (40) on the digital signal power. A control sub-channel (57), sometimes referred to as an auxiliary overhead channel is used to transmit control information which is interpreted by the receiver to identify the location and potentially the mode of the digital signals.