Digital signal

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

Analog-digital converter circuit

Abstract: The present invention provides a multi-input A/D converter circuit capable of shorting a conversion time without increasing its layout area and current consumption. When a most significant bit of a binary counter is “L”, individual input signals are sampled by a sample and hold unit, and digital signals held in respective data holders are sequentially selected by a selector. When the most significant bit is brought to “H”, the respective input signals are held as analog signals and compared with each of reference voltages produced corresponding to a digital signal by a DAC. When decision signals outputted from comparators are changed from “L” to “H”, the digital signal at that time is held in the individual data holders as digital signals.

Electroencephalic neurofeedback apparatus and method for bioelectrical frequency inhibition and facilitation

Abstract: An improved method and apparatus for displaying and either inhibiting or promoting selected bioelectrical frequencies emitted by a living organism. The method includes the steps of detecting an analog bioelectrical signal, converting the signal to discrete digital signals representing corresponding frequencies and numerically analyzing the digital signals to determine the different bioelectrical frequencies emitted by the organism. Furthermore, a threshold amplitude associated with a selected digital signal can be established an auditory or visual signal can be sent to the organism to indicate whether the bioelectrical frequency under study is within or outside the threshold amplitude. With this information the organism can be taught to inhibit or facilitate the bioelectrical frequency. The apparatus comprises a pair of electrodes, an analog signal amplifier, an analog to digital converter, a selector to select a frequency of interest, a display monitor, and a computer to distinguish the digital signals as different frequencies, display the frequencies, and determine when the frequency is falling inside or outside a predetermined range. Also, a magnetic medium recording device is used to capture data. Finally, a lighting or sounding circuit is used to tell the organism whether the frequency under study is being inhibited or facilitated.

Digital optical transmitter

Abstract: A cable television system (100) having forward and reverse paths includes, in the reverse path, a digital optical transmitter (200) for receiving an RF signal, converting it to a digital signal, and adding a digital pilot tone thereto. A laser is driven in accordance with the summed digital signal to generate a digital optical signal representative of the pilot tone and the RF signal. The cable television system (100) also includes an optical receiver (305) for receiving the digital optical signal and recovering therefrom the RF signal and the pilot tone. The optical transmitter (200) and receiver (305) are coupled by fiber optic communication media (110).

Burst demodulator for establishing carrier and clock timing from a sequence of alternating symbols

Abstract: OF THE DISCLOSURE In a burst demodulator, an APSK burst signal containing a preamble of alternating "1" and "-1" symbols, followed by a data field is received and quasi-coherently demodulated into a baseband complex signal, which is converted to digital form such that each symbol of the complex signal yields N digital samples, with N being selected such that at least one of the N digital samples is closest to a signal point of the burst signal. A clock recovery circuit is responsive to the arrival of the burst for estimating the symbol timing of the burst signal from digital samples of the preamble. A digital sample is extracted from every N samples of the preamble in response to the estimated symbol timing so that it is most likely to be closest to the signal point. A carrier recovery circuit responds to the estimated symbol timing by estimating the carrier frequency and phase of the burst signal from the extracted digital samples to produce a complex carrier signal, which is multiplied with the extracted digital samples to recover the original signal. Memories are preferably provided to store the received burst signal. By repeatedly reading the preamble from the memories, the same symbols of the preamble can be used for clock timing and carrier phase recovery operations.

Modulation of a digital input signal using a digital signal modulator and signal splitting

Abstract: A digital signal modulator modulates a digital input signal (507) to drive a load (324) such as an opposed current amplifier or other opposed current converter. In one embodiment, a digital signal modulator modulates a digital input signal. Even and odd samples (S3) of the input signal propagates along two respective channels (signal paths PWMn, PWMp), which include further digital processing capabilities, such as pulse width modulation, to generate output signals appropriate for the topology of a load. Additionally, a bias signal (Vb) may be modulated with the digital input signal. By utilizing digital signal processing to modulate the input signal, various processing technologies are applied to the input signal.