Abstract:
An analog-to-digital converter circuit in a sampling data detection channel of a disk drive synchronously samples user data in the data track areas at a first quantization resolution and samples servo bursts from the spoke areas at a second quantization resolution effectively greater than said first quantization resolution. An offset circuit provides a predetermined analog offset signal to a combining circuit which combines it with an incoming analog signal to provide a composite signal during a spoke servo burst sampling interval. An analog-to-digital converter samples the composite signal during the servo spoke burst sampling interval, and synchronously samples the analog signal during a user data sampling interval. A digital averaging circuit averages the servo spoke samples over a predetermined averaging interval to provide averaged burst samples having increased bit resolution.
Abstract:
A system for analogue to digital conversion comprising a means (4) for receiving an input analogue signal, a dither generator for adding a dither signal and an analogue to digital converter (2) for converting the combined input signal and dither signal to a digital value, characterized in that the dither generator provides a dither signal of a form comprising a first periodic dither signal having superimposed and being shaped by a second signal having at least one component which varies the first periodic dither signal over at least one quantization interval of the analogue to digital converter.
Abstract:
A method and apparatus for enhancing the resolution of an analog-to-digital converter. The method uses the addition of a second analog waveform to a first analog signal which is to be converted. When the composite signal is converted to digital form, this enhances the effective resolution of the A/D converter with respect to the first signal. Integration of the composite digital signal causes the effects of the second waveform to average to zero. The result is an enhanced resolution signal without undesired effects of the added second signal.
Abstract:
A system for converting an audio or like data signal from digital to analog form, with the addition of dither (white noise) to the digital input, with or without the subsequent removal of the dither from the analog output, for the reduction of quantization noise. Included is a network of n adders, equal in number to the n bits of the coded data signal, for adding in bit parallel form the digital data signal and the digital dither signal. Generated by an analog dither generator, the dither signal is transformed by an analog to digital converter into an m bit coded digital output, m being less than n, prior to delivery to the adder network. Some, preferably all, of the m bits of the digital dither signal are each added to, for example, two different ones of the n bits of the digital data signal so that, for instance, an eight bits analog to digital converter can be used for the provision of a digital dither signal to be added to a 16 bits digital audio signal. The adder network is connected to a digital to analog converter for converting the bit parallel addition of the data and dither signals into analog form.
Abstract:
Transit-time based ultrasonic flow meter with analog-to-digital conversion for measuring ultrasonic signals, wherein accuracy of measurements is improved by making several measurements with different input offset, reference voltage,frame offset or sample rate in an analog-to-digital conversion stage.
Abstract:
A novel and useful LC-tank digitally controlled oscillator (DCO) incorporating a split transformer configuration. The LC-tank oscillator exhibits a significant reduction in area such that it is comparable in size to conventional ring oscillators (ROs) while still retaining its salient features of excellent phase noise and low sensitivity to supply variations. The oscillator incorporates an ultra-compact split transformer topology that is less susceptible to common-mode electromagnetic interference than regular high-Q LC tanks which is highly desirable in SoC environments. The oscillator, together with a novel dc-coupled buffer, can be incorporated within a wide range of circuit applications, including clock generators and an all-digital phase-locked loop (ADPLL) intended for wireline applications.
Abstract:
The invention relates to a method and a device for the digital transmission of analogue signals, whereby an oversampling in analogue-digital and digital-analogue converters is carried out. A digital-analogue conversion is thus carried out which is particularly suitable for VDSL systems. A transmitted digital transmission signal (110) is supplied to a mixing unit (201). The digital transmission signal (110) is superimposed on a received noise signal (211), in the mixing unit (201) and applied to a received noise source connection (209). An interpolation filter unit (203), combined with a serial noise generation device (205), provides an increase in the frequency band width such that a suitable oversampling is achieved.