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    Control circuitry for quartz crystal deposition monitor
    2.
    发明授权
    Control circuitry for quartz crystal deposition monitor 失效
    QUARTZ晶体沉积监测器的控制电路

    公开(公告)号：US5117192A

    公开(公告)日：1992-05-26

    申请号：US464371

    申请日：1990-01-12

    申请人： Clarence Hurd

    发明人： Clarence Hurd

    IPC分类号： G01B17/02 ,  C23C14/54 ,  G01B7/06 ,  G01R23/07 ,  G01R29/22

    CPC分类号： C23C14/546 ,  G01B7/066 ,  G01R23/07 ,  G01R29/22

    摘要： A monitoring circuit monitors a piezoelectric crystal for changes in its resonant frequency as a film of material is vacuum deposited on it, e.g. to control a source of vapors of the material. A controllable frequency generator generates a drive signal of a accurately known frequency and phase within a band of RF frequencies that includes the resonant frequency of the crystal. The RF signal is applied through a duplexing circuit to the crystal, and a response signal is applied through the duplexing circuit to a signal amplifier and limiter circuit to a phase detector. The phase detector is also supplied with the RF drive signal, and has a phase output signal which is zero when the crystal is at resonance, and is negative or positive when the applied RF signal is below or above resonance, respectively. A micro-controller can be employed for controllably sweeping the frequency of the drive signal and then monitoring the frequencies at which the phase detector signal indicates zero, to identify the frequency of each of the one or more resonances. A cable compensation control circuit can also be coupled to the duplexing circuit for balancing the reactance of the conductive paths associated with the crystal. This can include a voltage controlled capacitance and a portion of a transformer within the duplexing circuit.

    摘要翻译： 监测电路监测压电晶体的谐振频率的变化，因为材料的膜被真空沉积在其上。 以控制材料的蒸气源。 可控频率发生器产生包括晶体的谐振频率的RF频率的频带内的精确已知频率和相位的驱动信号。 RF信号通过双工电路施加到晶体，并且响应信号通过双工电路施加到信号放大器和限幅器电路到相位检测器。 相位检测器也被提供有RF驱动信号，并且当晶体处于谐振时具有为零的相位输出信号，当施加的RF信号低于或高于谐振时，相位检测器为负或正。 可以使用微控制器来可控地扫描驱动信号的频率，然后监视相位检测器信号指示零的频率，以识别一个或多个谐振中的每一个的频率。 电缆补偿控制电路还可以耦合到双工电路，用于平衡与晶体相关联的导电路径的电抗。 这可以包括压控电容和双工电路内的变压器的一部分。

    Acoustic sensor for in-line continuous monitoring of gasses
    4.
    发明授权
    Acoustic sensor for in-line continuous monitoring of gasses 失效
    用于气体连续监测的声学传感器

    公开(公告)号：US5768937A

    公开(公告)日：1998-06-23

    申请号：US748599

    申请日：1996-11-13

    申请人： Abdul Wajid ,  Clarence Hurd ,  Melvin C. Hetzel

    发明人： Abdul Wajid ,  Clarence Hurd ,  Melvin C. Hetzel

    IPC分类号： G01F1/66 ,  G01N29/036 ,  G01N29/22 ,  G01F17/00

    CPC分类号： G01N29/036 ,  G01F1/662 ,  G01F1/667 ,  G01N29/22 ,  G01N2291/0222 ,  G01N2291/02836 ,  G01N2291/02881

    摘要： An acoustic cell includes multiple acoustic cavities fluidly coupled together. At least two of the acoustic cavities have unequal lengths and cross sections. End segments of the acoustic cell are uniformly cylindrically shaped or conically shaped. A driver transducer at one end of the acoustic cell and a receiver transducer at another end of the acoustic cell are acoustically isolated from the acoustic cell. A pair of preferably metallic isolation diaphragms transmit acoustic signals to and from the transducers without significantly altering the phase-frequency characteristics of the acoustic signals. The acoustic cell operates as an acoustic resonator operating at frequencies lower than any possible self-resonance frequencies of the isolation diaphragms or the driver and receiver transducers. When a binary gas is flowed through the cell, a processor detects a resonant frequency of the gas within the cell to determine a composition of the gas.

    摘要翻译： 声学单元包括流体耦合在一起的多个声腔。 至少两个声腔具有不相等的长度和横截面。 声学单元的端部段是均匀的圆柱形或圆锥形的。 在声学单元的一端处的驱动器换能器和声学单元的另一端处的接收器换能器与声学单元进行声学隔离。 一对优选的金属隔离膜片将声信号传递到换能器而不显着地改变声信号的相位频率特性。 声学单元作为声学谐振器工作，频率低于隔离隔膜或驱动器和接收器换能器的任何可能的自谐振频率。 当二进制气体流过电池时，处理器检测电池内的气体的共振频率以确定气体的组成。