Digital signal

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

Adc transfer function providing improved dynamic regulation in a switched mode power supply

Abstract: A power supply comprises at least one power switch adapted to convey power between input and output terminals of the power supply, and a digital controller adapted to control operation of the at least one power switch responsive to an output measurement of the power supply. The digital controller comprises an analog-to-digital converter providing a digital error signal representing a voltage difference between the output measurement and a reference value, a digital filter providing a digital control output based on a sum of previous error signals and previous control outputs, an error controller adapted to modify operation of the digital filter upon an error condition, and a digital pulse width modulator providing a control signal to the power switch having a pulse width corresponding to the digital control output. The analog-to-digital converter further comprises a windowed flash analog-to-digital converter having a transfer function defining a relationship between the voltage difference and corresponding digital values. The transfer function provides a substantially linear region at a center of a corresponding error window, including a first step size in the center of the error window and at least one other step size in a peripheral region of the error window that is larger than the first step size. The first step size and the other step sizes may each reflect a linear relationship between the voltage difference and the corresponding digital values. Alternatively, the first step size reflects a linear relationship between the voltage difference and the corresponding digital values, and the other step sizes each reflect a non-linear relationship between the voltage difference and the corresponding digital values.

Enhanced delta modulation encoder

Abstract: An improved analog-to-digital encoder comprising an enhanced delta modulation encoder. The enhanced delta modulation encoder includes a spectrum tilter, a 1 bit analog-to-digital converter, a sampling circuit and an internal decoder. An analog input signal and an internal analog signal from the internal decoder are summed to provide an analog dither which is essentially an internal error signal. The analog dither signal is tilted by the spectrum tilter and is provided to the 1 bit analog-to-digital converter which generates a digital signal. The sampling circuit receives the digital signal from the analog-to-digital converter and generates a digital output which is fed back to the internal decoder. The spectrum tilter comprises at least three integrator circuits and a clipping circuit connected in parallel to two of the three integrator circuits. The three integrator circuits tilt the frequency spectrum of noise above the maximum frequency of interest, and the clipping circuit prevents the encoder from becoming unstable. A digital filter may be connected to the output of the sampling circuit in order to filter the digital output to make it compatible with systems commonly employed to process the digital output.

MicroUnity's MediaProcessor architecture

Abstract: This media processor extends general-purpose computer systems for communicating and processing digital video, audio, data, and radio frequency signals at broadband rates.

Recognition of a received signal as being from a particular transmitter

Abstract: A system for recognizing a received encoded signal as being from a particular transmitter is disclosed. An encoder encodes a signal to have a predetermined sequence of pulses of three different predetermined sequence of pulses of three different predetermined durations within a constant bit interval in accordance with a trinary code; wherein each of the different predetermined durations corresponds to a different bit. A decoder is coupled to the receiver for recognizing the received encoded signal as being from the particular transmitter includes a programmable digital logic signal generator that is programmed in accordance with the trinary code for generating a programmed digital logic signal having a predetermined sequence of different digital words corresponding to the predetermined sequence of pulses of different predetermined durations in the transmitted encoded signal; a code converter for converting the received encoded signal to a decoded digital logic signal having digital words in accordance with the selected code by measuring and comparing the relative durations of the pulse and the non-pulse time during each bit interval; a comparator for comparing the decoded digital logic signal with the programmed digital logic signal; and a control logic circuit coupled to the programmable signal generator, the code converter and the comparator for synchronizing the programmed digital logic signal with the decoded digital logic signal and for recognizing the received encoded signal as being from the transmitter when said comparison indicates a predetermined number and sequence of valid comparisons between the decoded digital logic signal and the programmed digital logic signal.

Digital feedforward sigma-delta modulator in analog-to-digital converter and modulation method thereof

Abstract: A digital feedforward sigma-delta modulator in an analog-to-digital converter and its modulation method are disclosed The modulator changes a feedforward path from an analog domain to a digital domain and processes it The modulator integrates an analog input by using a plurality of integrators, weights them, quantizes them by using a plurality of quantizers in a digital domain to output digital signals, and then adds up the thusly outputted digital signals by using a digital adder In case of a continuous time digital feedforward sigma-delta modulator (SDM), a digital signal outputted from the digital adder is weighted and then immediately inputted to the digital adder in the digital domain so as to be subtracted, allowing for digital feedforwarding Because the feedforward signal is processed in the digital domain, the area occupied by an analog circuit and power consumption can be reduced Also, because signals are added up in the digital domain, a digital output signal can be immediately used when an excess loop delay needs to be corrected Thus, because there is no need to convert the digital output signal into an analog signal by using a DAC, the DAC can be omitted