Methods of generating a gradient waveform, gradient waveform generators and magnetic resonance imaging systems are provided. In one aspect, a first digital value is obtained by quantizing and coding spatial position information of a voxel of a subject according to the number of preset quantization bits, wherein the number of the quantization bits are more than the number of allowed input bits for a DAC; a second digital value is determined to be inputted into the DAC according to the first digital value and the number of the allowed input bits for the DAC; a quantization error is determined according to the first digital value and the second digital value; an error accumulating value is updated by accumulating the quantization error to the error accumulation value; the second digital value corrected according to the error accumulation value; and the corrected second digital value is inputted into the DAC.

The invention relates to a method for controlling digital-to-analogue converters (DAC), the method comprising: providing a plurality of digital-to-analogue converters (DAC) of a multi-channel converter array wherein each DAC includes a separate clock generator; generating, by each clock generator, a RF carrier signal; converting, by each DAC, digital data signals into analogue RF data signals based on the carrier signals of the corresponding clock generators; providing a separate control signal for each clock generator wherein the control signals comprise control information such that when the control signals are applied to the corresponding clock generators the different analogue RF data signals provided at respective output terminals of each DAC comprise a pre-defined phase shift to each other; controlling the clock generator of each DAC directly and independently based on the provided control signals. The invention further relates to a converter arrangement RF transmit circuit arrangement.

Methods and systems are provided for using localized dynamic element matching (DEM) and/or dynamic noise scaling (DNS) in digital-to-analog converters (DACs). Adaptive (localized) DEM may be applied in a DAC, by selecting one or more of a plurality DAC elements in the DAC, forcing the selected one or more of the plurality of DAC elements not to switch during digital-to-analog conversions, and scrambling remaining one or more of plurality of DAC elements when generating an output of the DAC. The adaptive DEM may be applied when the DAC input is backed off from full-scale. DNS may be applied in a DAC, by adaptively selecting one or more of a plurality DAC elements in the DAC and switching off the selected one or more of the plurality DAC elements such that the selected one or more of the plurality DAC elements do not contribute to generating an output of the DAC.

Methods and systems are provided for using localized dynamic element matching (DEM) and/or dynamic noise scaling (DNS) in digital-to-analog converters (DACs). Adaptive (localized) DEM may be applied in a DAC, by selecting one or more of a plurality DAC elements in the DAC, forcing the selected one or more of the plurality of DAC elements not to switch during digital-to-analog conversions, and scrambling remaining one or more of plurality of DAC elements when generating an output of the DAC. The adaptive DEM may be applied when the DAC input is backed off from full-scale. DNS may be applied in a DAC, by adaptively selecting one or more of a plurality DAC elements in the DAC and switching off the selected one or more of the plurality DAC elements such that the selected one or more of the plurality DAC elements do not contribute to generating an output of the DAC.

A digital-to-analog converter including a resistor string configured to provide a plurality of gradation voltages formed by receiving a top voltage at one end thereof and a bottom voltage at the other end; a plurality of pass transistors including a pass transistor having one end which is electrically connected to the resistor string and outputting any one among the plurality of gradation voltages; and a decoder configured to control the plurality of pass transistors. The plurality of the pass transistors are included in any one among a plurality of groups according to values of the gradation voltages, and the pass transistors included in the any one group are divided into a first group and a second group according to output gradation voltages, and pass transistors included in the first group and pass transistors included in the second group are different types of pass transistors.

Various examples are directed to crosspoint switches and methods of use thereof. An example cross point switch comprises a first row buffer, a second row buffer, a first column buffer, and a second column buffer. The crosspoint switch may also comprise a first switch that, when closed, electrically couples the second row buffer to the first column buffer, and a correction controller. The correction controller may be configured to send a first correction signal to the first row buffer, send a second correction signal to the second row buffer; receive an indication that the first switch is closed, send a third correction signal to the first column buffer; and send a fourth correction signal to the second column buffer.

Various examples are directed to crosspoint switches and methods of use thereof. An example cross point switch comprises a first row buffer, a second row buffer, a first column buffer, and a second column buffer. The crosspoint switch may also comprise a first switch that, when closed, electrically couples the second row buffer to the first column buffer, and a correction controller. The correction controller may be configured to send a first correction signal to the first row buffer, send a second correction signal to the second row buffer; receive an indication that the first switch is closed, send a third correction signal to the first column buffer; and send a fourth correction signal to the second column buffer.

Systems and methods for providing an output signal based at least in part upon an input signal and a clock signal in a manner in which jitter is avoided or diminished, including for example a digital-to-analog converter (DAC), are disclosed herein. In one example embodiment, such a system includes an output signal generating component, a first component having a first switch and a variable characteristic, and a plurality of second components each having a respective additional switch and a respective fixed characteristic. A value of the variable characteristic is set at least in part based upon input and clock signals so that, when the variable characteristic influences at least indirectly the generating of the output signal by the output signal generating component, the output signal attains a first level that at least indirectly depends upon a phase of the clock signal relative to the input signal.

This disclosure describes a precise, fast, and relatively low power current-source for use in various applications, which may include driving power semiconductors such power MOSFETs and IGBTs. The current-source may provide both a constant current and a current profile over time which may charge and discharge the steering terminal (e.g. the gate) of a power semiconductor for precise control of switch timing. The current-source uses current steering digital-to-analog converter (DAC) technology and current mirrors to generate a high output current that is significantly immune to power supply and ground variability.

This disclosure describes a precise, fast, and relatively low power current-source for use in various applications, which may include driving power semiconductors such power MOSFETs and IGBTs. The current-source may provide both a constant current and a current profile over time which may charge and discharge the steering terminal (e.g. the gate) of a power semiconductor for precise control of switch timing. The current-source uses current steering digital-to-analog converter (DAC) technology and current mirrors to generate a high output current that is significantly immune to power supply and ground variability.