Abstract:
PROBLEM TO BE SOLVED: To solve the problem that a continuous time output stage of a DAC (digital to analog converter) requires a method of minimizing inter-symbol interference and improving effects of clock characteristics. SOLUTION: The digital to analog converter (Fig 1A) includes a noise shaping modulator (102) for modulating an input digital data stream (101), a plurality of output elements (103) for generating a plurality of intermediate data streams from a modulated output stream from the modulator, and an output summer (106) for summing the intermediate data streams to generate an output analog stream. The noise shaping modulator balances an edge transition rate of the output elements so that the edge transition rate of two selected elements is approximately equal. COPYRIGHT: (C)2008,JPO&INPIT
Abstract:
PROBLEM TO BE SOLVED: To provide improved techniques for reducing noise in a delta-sigma modulator. SOLUTION: An integrator stage for use in a delta-sigma modulator includes an operational amplifier (312), an integration capacitor (C I ) coupling an output of the operational amplifier (312) and a summing node at an input side of the operational amplifier, and a feedback path. The feedback path includes first and second capacitors (+C REF ) and (-C REF ) having first plates coupled electrically in common at a common plate node and switching circuitry (310a-310d) for sampling selected reference voltages onto second plates of the capacitors during a sampling phase. The integrator stage further includes a switch (305a, 305b) for selectively coupling the common plate node and the summing node during an integration phase. COPYRIGHT: (C)2007,JPO&INPIT
Abstract translation:要解决的问题:提供用于降低Δ-Σ调制器中的噪声的改进技术。 解调器:用于Δ-Σ调制器的积分器级包括运算放大器(312),耦合运算放大器(312)的输出的积分电容器(C I SB>)和 在运算放大器的输入侧的求和节点和反馈路径。 反馈路径包括第一和第二电容器(+ C REF SB>)和(-C REF SB>),其中第一板在公共板节点处共同电耦合,并且开关电路 -310d),用于在采样阶段将所选参考电压采样到电容器的第二板上。 积分器级还包括用于在积分阶段期间选择性地耦合公共板节点和求和节点的开关(305a,305b)。 版权所有(C)2007,JPO&INPIT
Abstract:
PROBLEM TO BE SOLVED: To realize a discrete time filter of a higher order and an analog filter of a lower order by using a sampling read channel which is provided with a sampling device, with an adaptive equalizer, with a restriction circuit and with a discrete time sequence detector. SOLUTION: In a sampled amplitude read channel, an interpolated timing recovery B100 is provided instead of a conventional sampling timing recovery. In addition, a write frequency synthesizer 52 generates a baut rate write clock 54 which is given to a write circuit 9. A sampling device 24, a discrete time equalizer filter B103 and the interpolated timing recovery B100 generate an asynchronous read clock 54 which is clock-matched at a frequency CDR 30 with reference to a present zone.