Abstract: The present invention discloses a method for obtaining frequency parameters to determine the resonator inductances of a crystal. Under this method, a plurality of frequencies are applied to a first electrode. This application is performed once while the second electrode and the common electrode are connected by a short circuit, and then again when the second electrode and the common electrode are capactively connected or open circuited. During each application of the plurality of frequencies to the crystal, the phase response for the output of the resonator circuit is monitored. Then the time response of the crystal is determined. Next, the time delay relative maxima for the time response is determined. Finally, the frequencies at which the time delay relative maxima occur are determined. These frequencies correspond to the inflection points where the change in phase goes from monotonically increasing to monotonically decreasing.

Abstract: A method of rotating a non-temperature compensated Bechmann curve of a quartz strip. The method includes the steps of determining (102) whether a crystallographic orientation of an AT cut quartz strip is within a desired specification; selecting (104) a predetermined nominal electrode coverage having a nominal electrode width for an in-specification AT cut quartz strip; and tuning (106) an out of specification crystallographic orientation, by: adjusting (108) the electrode width with respect to the nominal electrode width, to bring the out-of-specification crystallographic orientation of an out-of-specification AT cut crystal quartz to within a desired specification having an in-specification Bechmann curve with an inflection point; and rotating (110) an out-of-specification Bechmann curve about the inflection point to substantially approach the desired in-specification Bechmann curve.

Abstract: A carriage or dielectric disk (40) has a series of electrical contacts (46, 48) defined by conventional circuit board techniques on upper and lower surfaces around a peripheral edge. Sockets (42, 44) are wave soldered in electrical connection with the electrical contacts. At least the electrical contacts are plated with a hard, dense metal, such as nickel. When components have been frictionally inserted into the sockets, the carriage is placed in a cooling chamber (18). Air of a selected temperature is blown through a central port (22) and directed to flow over the surface of the carriage and the supported components (10). A motor (60) rotates the carriage to move the electrical contacts (46, 48) successively into electrical communication with relatively soft electrical contact springs (58) connected with a test instrument (32). The test circuit measures electrical characteristics or properties of each component at each of a plurality of preselected temperatures.

Abstract: Equivalent circuit parameters of a piezoelectric resonator are measured in order to precisely control the amplitude and/or frequency of oscillation of an oscillator including the resonator, or to compensate for variations in the amplitude and/or frequency of oscillation. Significant variations are caused by shunt capacitance, and to a lesser degree, series resistance. The equivalent circuit parameters are measured by exciting the resonator at a plurality of frequencies, measuring responses of the resonator at the frequencies, including a complex response at one of the frequencies, and determining a value of the shunt capacitance from the responses. Preferably, the resonator is simultaneously and continuously excited at three different frequencies, one of which is approximately the resonant frequency of the resonator.

Abstract: A piezoelectric body polarizing apparatus including a DC power supply 2 for applying a DC voltage to a piezoelectric body 1 to polarize the piezoelectric body 1, an impedance measuring circuit 4 for measuring the change in impedance of the piezoelectric body 1, a high frequency power supply 5, and a DC current blocking filter 3 connected between a high frequency portion, which is constituted by the impedance measuring circuit 4 and the high frequency power supply 5, and the piezoelectric body 1. The DC current blocking filter 3 includes at least a DC current blocking capacitor C.sub.1 and a transient current bypass capacitor C.sub.2 connected between a node A, between the DC current blocking capacitor C.sub.1 and the high frequency portion, and a ground potential.

Abstract: This invention relates to a method of testing multi-channel array pulsed droplet deposition apparatus (10) comprising a multiplicity of parallel channels (12) each with pulse imparting means for expelling droplets therefrom. The apparatus is located opposite a test module (20) having detecting elements (21) with channels of the apparatus opposed and close to the respective elements. Coupling fluid (23) fills the channels (12) to be tested and the space between the apparatus and the test module. Test signals are applied to impart energy pulses to the fluid in the channels opposite the detecting elements so that signals are passed to those elements by way of the fluid which are evaluated to assess the channel performance. Various forms of the detector elements and the apparatus are disclosed.

Abstract: A micro-miniature resonator-oscillator is disclosed. Due to the miniaturization of the resonator-oscillator, oscillation frequencies of one MHz and higher are utilized. A thickness-mode quartz resonator housed in a micro-machined silicon package and operated as a "telemetered sensor beacon" that is, a digital, self-powered, remote, parameter measuring-transmitter in the FM-band. The resonator design uses trapped energy principles and temperature dependence methodology through crystal orientation control, with operation in the 20-100 MHz range. High volume batch-processing manufacturing is utilized, with package and resonator assembly at the wafer level. Unique design features include squeeze-film damping for robust vibration and shock performance, capacitive coupling through micro-machined diaphragms allowing resonator excitation at the package exterior, circuit integration and extremely small (0.1 in. square) dimensioning.

Abstract: A monolithic coupled-dual resonator crystal filter coupled to improve switching arrangements is tested using both resonator ports to quickly measure selected resonator parameters useful in frequency adjustment, production and test systems as well as accurately measuring other filter crystal parameters, all without requiring removal of the crystal structure from the test fixture.

Abstract: 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.

Abstract: In coupled-dual resonator crystals, key parameters, such as resonator frequencies and synchronous peak separation frequency, are determined using a four frequency measuring process and apparatus wherein additional impedance is connected in parallel with the driving point impedance of the input resonator so as to allow the measurement of the critical frequencies above about 45 MHz.

Abstract: A third case or manner of obtaining the four critical frequencies useful in accurately measuring coupled-dual resonator crystals, wherein both ports of the crystal structure are monitored, rather than a single port in the previously known cases. Here the B port, for example, is monitored with the A-side open-circuited or with a capacitor in parallel with it, and the A port is monitored with the B-side short-circuited.

Abstract: The invention relates to a method and apparatus for testing the response of a stress wave sensor to confirm that the transducer and amplifier are functioning satisfactorily.A pulser is connected to the stress wave sensor at a point between the transducer and the amplifier. The pulser supplies a first and a second electrical pulse in series to the stress wave sensor. The first electrical pulse has a large amplitude such that it causes an operative transducer to oscillate and produce an additional electrical pulse. The first electrical pulse and the additional electrical pulse are supplied to the amplifier. An operative amplifier amplifies the first electrical pulse and any additional pulse to give an output signal, the output signal indicates if either the transducer or amplifier are not operating satisfactorily, the lack of an output signal indicates the amplifier is inoperative.

Abstract: There is disclosed herein a driver system for an ultrasonic probe for allowing a user to have proportional control of the power dissipated in the probe in accordance with the position of power dissipation controls operable by the user and for automatically tuning upon user request such that the driving frequency is equal to the mechanical resonant frequency of said probe and such that the reactive component of the load impedance represented by said probe is tuned out. The system uses a tunable inductor in series with the piezoelectric crystal excitation transducer in the probe which has a flux modulation coil. The bias current through this flux modulation coil is controlled by the system. It is controlled such that the inductance of the tunable inductor cancels out the capacitive reactance of the load impedance presented by the probe when the probe is being driven by a driving signal which matches the mechanical resonance frequency of the probe.

Abstract: A method for testing body components of pulsed droplet deposition apparatus comprises applying a variable frequency voltage to the electrodes of each of a number of selected channel wall elements. The resulting impedance variations are used to determine the natural frequencies of the selected wall elements which, in turn, are used to determine whether the compliance ratios of the selected wall elements and the droplet liquid to be used therewith lies within a desired range of values.

Abstract: A diesel engine exhaust system is provided with a particulate trap for collecting the products of incomplete combustion during the engine power cycle. A sensing mechanism including an electrode downstream of the trap and a signal generating circuit provides a positive indication of occurrence of regeneration of the trap. Charged particles generated during regeneration induce a charge of the electrode, that charge activates the signal generating circuit and it, in turn, produces an indication external of the exhaust system that trap regeneration is occurring. That indication can be in the operator's compartment.

Abstract: The thermal hysteresis of quartz crystal resonators is measured by exciting two modes of a quartz crystal of interest with an external frequency source at a preselected temperature, calculating the difference frequency as between the modes, resetting to the original set temperature after temporarily altering the temperature, remeasuring the frequencies while maintaining the temperature and the difference frequency at the same respective values as the original values, and taking the mode frequency difference as representative of the thermal hysteresis of the crystal.