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13 条记录 (耗时 0.022 秒)

    Time based digital-to-analog conversion of a precision variable amplitude sine wave
    3.
    发明授权
    Time based digital-to-analog conversion of a precision variable amplitude sine wave 有权
    基于时间的数模转换精度可变幅度正弦波

    公开(公告)号：US06191721B1

    公开(公告)日：2001-02-20

    申请号：US09435000

    申请日：1999-11-05

    申请人： Gregory M. Johnson ,  John C. Baker ,  Daniel T. Zaida ,  Patrick A. Toole

    发明人： Gregory M. Johnson ,  John C. Baker ,  Daniel T. Zaida ,  Patrick A. Toole

    IPC分类号： H03M166

    CPC分类号： G06F1/025

    摘要： A time based digital to analog converter is presented in which known reference voltages are used to create variable period waveforms which, when combined according to a desired computation, can convert digital words into a sinusoidal signal of a precision variable. To illustrate the application of the present invention, a hemispherical resonator gyroscope (HRG) operating in force rebalance is presented wherein a time based digital to analog converter with a variable period output controls the HRG electronics in nulling the standing wave. A rate of the standing wave is calculated, and a software component calculates the fraction of the maximum rate needed to oppose and null the initial rate of the standing wave. The fraction of the maximum rate is converted to digital words corresponding to the number of periods of a clock connected to the circuit. Using the digital words thus determined, a gate array using digital logic generates waveforms having variable periods, where the amplitude of the waveforms correspond to fixed reference voltage sources, and the period of the waveforms are determined by the digital words in the earlier calculation. Using the waveforms, the HRG rate controls can be maintained at a high level of precision.

    摘要翻译： 提出了一种基于时间的数模转换器，其中使用已知的参考电压来创建可变周期波形，当根据期望的计算组合时，可以将数字字转换成精度变量的正弦信号。 为了说明本发明的应用，提出了一种有效重新平衡的半球谐振器陀螺仪（HRG），其中具有可变周期输出的基于时间的数模转换器控制HRG电子设备使驻波归零。 计算驻波的速率，软件组件计算反对所需的最大速率的分数，并将驻波的初始速率置零。 最大速率的分数被转换成与连接到电路的时钟的周期数相对应的数字字。 使用如此确定的数字字，使用数字逻辑的门阵列产生具有可变周期的波形，其中波形的幅度对应于固定参考电压源，并且波形的周期由较早计算中的数字字确定。 使用波形，HRG速率控制可以保持高精度。

    Ophthalmic compositions and methods for preserving and using same
    6.
    发明授权
    Ophthalmic compositions and methods for preserving and using same 失效
    眼用组合物及其保存和使用方法

    公开(公告)号：US5387394A

    公开(公告)日：1995-02-07

    申请号：US59522

    申请日：1993-05-11

    申请人： John C. Baker

    发明人： John C. Baker

    IPC分类号： A61K36/75 ,  A61L12/14 ,  A61P27/02 ,  C11D3/00 ,  A01N25/02 ,  A61L2/18

    CPC分类号： C11D3/0078 ,  A01N65/36 ,  A61L12/14 ,  Y10S514/84

    摘要： Ophthalmic compositions, such as those used to care for contact lenses, methods of preserving such compositions, and methods for disinfecting contact lenses using such compositions are disclosed. The compositions may comprise an ophthalmically acceptable, liquid aqueous medium and, included therein, an effective preserving or disinfecting amount of grapefruit seed extract.

    摘要翻译： 公开了眼用组合物，例如用于护理隐形眼镜的那些，保存该组合物的方法，以及使用这种组合物消毒隐形眼镜的方法。 组合物可以包含眼科可接受的液体水性介质，并且其中包括有效的保存或消毒量的葡萄柚种子提取物。

    Vibratory sensor with virtual node/antinode correction of secondary harmonics
    10.
    发明授权
    Vibratory sensor with virtual node/antinode correction of secondary harmonics 有权
    具有虚拟节点的振动传感器/二次谐波的波腹校正

    公开(公告)号：US06357296B1

    公开(公告)日：2002-03-19

    申请号：US09434983

    申请日：1999-11-05

    申请人： John C. Baker ,  Daniel T. Zaida ,  Gregory M. Johnson

    发明人： John C. Baker ,  Daniel T. Zaida ,  Gregory M. Johnson

    IPC分类号： G01P904

    CPC分类号： G01C19/56

    摘要： A vibratory sensor with a resonator for measuring angular rotation, such as for example a hemispherical resonator gyroscope (HRG) operating in force rebalance mode, includes circuitry to generate a virtual node and antinode in the resonator standing wave. Shifting a pair of pickoff electrodes from a position directly over an actual node in the HRG standing wave to an offset position where the primary and secondary harmonic contributions at the first pickoff electrode are equal to the primary and secondary harmonic contributions at the second pickoff electrode permits the elimination of secondary harmonics contribution. A virtual node is created by offsetting a pair of pickoff electrodes 22.5 degrees from the actual antinode such that each pickoff electrode includes an equal contribution of the secondary harmonic signal present in the standing wave. Differencing the two signals eliminates both the primary signal contribution as well as the secondary harmonic signal contribution, thereby reducing the signal below the actual node signal. The virtual node can then be amplified to a greater extent without the filtering and shifting that is ordinarily required of the signal processing at the actual node. While the virtual antinode includes contributions of the secondary harmonic signal at both pickoff electrodes, the peak amplitude of the secondary harmonic is typically only one percent of the primary vibration pattern and does not adversely affect the processing of the virtual antinode. Using a circuit which adds and differences the two inputs requires only two additional buffers and results in a vibratory sensor with significantly better accuracy.

    摘要翻译： 具有用于测量角度旋转的谐振器的振动传感器，例如在力重新平衡模式下操作的半球谐振器陀螺仪（HRG），包括在谐振器驻波中产生虚拟节点和波腹的电路。 将一对拾取电极从直接在HRG驻波中的实际节点上的位置移动到偏移位置，其中第一检测电极处的初级和次级谐波贡献等于第二检测电极处的一次和二次谐波贡献允许 消除二次谐波贡献。 通过将距离实际波腹22.5度的一对拾取电极偏移，使得每个拾取电极包括存在于驻波中的二次谐波信号的相等贡献来创建虚拟节点。 差分两个信号消除了主要信号贡献以及二次谐波信号贡献，从而减少了低于实际节点信号的信号。 然后可以在更大程度上放大虚拟节点，而不需要在实际节点处进行信号处理通常需要的滤波和移位。 虽然虚拟波腹包括在两个拾取电极处的二次谐波信号的贡献，但是二次谐波的峰值振幅通常仅为主振动模式的一个百分点，并且不会对虚拟波腹的处理产生不利影响。 使用增加和差异两个输入的电路只需要两个额外的缓冲器，并产生具有更好精度的振动传感器。