Abstract:
A data receiver has a digital filter which is adaptively tuned to the instantaneous bit-rate of a received noisy digital signal so as to provide an optimum transfer function despite irregularities in the received signal. A timing signal which reflects the true rate of the received signal adaptively tunes the filter, and sets the bit-rate at which the filter output is digitized. The data receiver output is a digital signal which is a reconstruction of the information content of the received digital signal with low probability of error.
Abstract:
A fully digital spectrum analyzer accepting as an input either an analog signal or a series of digital numbers and using time compression and DFT (Discrete Fourier Transform) techniques to provide the spectral component values of the input signal. Novel techniques and means are used in obtaining the power values for selected spectral lines and in averaging these power values. Statistically controlled noise is added to the input of the spectrum analyzer to enhance its resolutin beyond the resolution which would be otherwise available. Advanced and efficient techniques are used for generating and applying trigonometric functions in the course of finding the real and imaginary part of Fourier transforms, and for providing running averages of the power spectra.
Abstract:
In the preferred embodiment of the invention disclosed herein, a new and improved well tool which is adapted to be coupled in a drill string adjacent to a drill bit includes inner and outer telescoping members which are cooperatively arranged to define an expansible sample chamber for entrapping a discrete sample of drilling mud from a borehole adjacent to the drill bit in a drill string upon telescoping movement of the inner and outer members. Valve means are cooperatively arranged between the telescoping members for selectively closing the sample chamber upon further movement of the telescoping members to expand the sample chamber. In this manner, by coupling force-measuring means to a drill string coupled to the tool the force required to fully expand the chamber is measured for providing a surface indication which is indicative of the percentage of gas entrained in the collected sample.
Abstract:
In the preferred embodiment of the invention disclosed herein, inner and outer telescoping members coupled in a drill string adjacent to a drill bit are cooperatively arranged to define an expansible sample chamber for entrapping a discrete sample of drilling mud from the borehole adjacent to the drill bit upon telescoping movement of the inner and outer members. Valve means are cooperatively arranged between the telescoping members for selectively closing the sample chamber upon further movement of the telescoping members to expand the sample chamber. Forcemeasuring means are coupled to the drill string for measuring the force required to fully expand the chamber and thereby providing a surface indication which is indicative of the percentage of gas entrained in the collected sample.
Abstract:
A digital ohmmeter having a differential amplifier with a capacitor connected between the output and the inverting input to form an integrator. A source of DC voltage is connected to a series circuit including the unknown resistor and to a switch which selectively connects the source to a second series circuit, an intermediate point of which is connected to the inverting terminal of the amplifier. The unknown resistor is connected to the noninverting input. The output of the amplifier is connected to logic circuit and counting means of the type used in dual slope integrating digital voltmeters, and others such as voltageto-frequency converters, with the logic means having an output to control the switch means. The switch is open for a fixed interval and closed for a variable interval, which variable interval is counted as a measure of the input resistance. In this embodiment, the two series resistance circuits form a bridge when the switch is closed. In a second embodiment an additional switch connects the second series circuit to ground when it is disconnected from the source. In either embodiment the resistance value is linearly proportional to the length of the variable interval of time multiplied by a constant, the constant being determined by the fixed resistors in the two series circuits.
Abstract:
An illustrative embodiment of the invention is directed to method and apparatus for manufacturing microchannel devices. Typically, the individual glass tubes in a hexagonal bundle are sealed on one end to individual hangers from which they are suspended vertically in a furnace. A vacuum is drawn within the furnace so that the inner surfaces of the tubes, exposed to atmospheric pressure, will not collapse during heating and drawing. At temperature, the bundle is drawn and elongates under the controlled forces applied through a modified Atwood''s machine to reduce the bundle cross section by a ratio of about 50 to 1. The elongated bundle is cut into lengths as it is drawn, and these individual lengths are stacked together within a tube of glass that has a higher melting point than the glass in the drawn lengths. The channels are once more sealed and the assemblies are subjected to a secondary fusion process prior to slicing into thin discs. The annular glass rings are removed from the discs and the microstructures are placed in a molten wax bath in order to fill the channels with wax before grinding and polishing. After grinding and polishing, the wax is removed.
Abstract:
A device for correcting the time relationship of parallel data bits to eliminate the effect of certain forms of static skew. The apparatus accepts the data bits on parallel channels, one of which is arbitrarily designated as the ''''master channel,'''' the others being slave channels. Logic associated with the master channel generates an early gate signal upon arrival of a master channel data bit, and a late gate signal is generated, also as a result of the data bit arrival. An interval between the early gate and the late gate defines a ''''window'''' in time within which the apparatus produces a master channel data bit out, delayed by a predetermined amount, and within which the slave channel data bits should occur. If the slave channel data bits do not occur within this window, delay means in each slave channel is altered to readjust the occurence of the data bit out. Each slave channel is adjusted individually in accordance with the gate signal so that, after cyclic adjustment, the data bits are in essential coincidence. The interval between the early and late gate is adjustable by a sensitivity control to determine the accuracy of coincidence desired.
Abstract:
An analog-to-digital converter of the dual slope integrating type operates without counter reset or input gating circuitry to provide successive, accurate digital readouts representing the average magnitude of corresponding analog input signals. Provision is made to nullify a predetermined number of transient waveforms which may be produced as an undesired by-product of dispensing with such circuitry. The converter employs a buffer storage register to receive and store the digital contents of a counter, which contents represent the average magnitude of the analog input signal. The storage register provides a digital readout, typically in the form of a visual display, which persists at least for a time interval which starts at the termination of one complete analog-to-digital conversion cycle and extends to the termination of a succeeding conversion cycle. In accordance with yet another aspect of this invention to polarity reversals of the analog signal, an offset current of constant magnitude is applied as an additional input signal to the integrator of the converter and appropriate compensation for that value of offset current is provided by the counter so that the display provides an indication only of the value of the analog input signal.
Abstract:
Fully encased adjustable resistors, typically rectilinear potentiometers, characterized by having at least two points of manipulation for adjustment. In a typical embodiment, a lead screw-operated rectilinear potentiometer has the head of the lead screw exposed at one end of the housing and is provided with an additional adjusting member the head of which is exposed through the top of the housing, the lead screw being provided with a helical gear portion and the additional adjusting member having a helical gear portion meshed therewith.
Abstract:
A push-button switch of the selective or latching type. A washer block-out mechanism co-operates with a tail portion of each pushbutton to positively prevent depressing more than one pivotally mounted push button to a contact make position. The push buttons are mounted in side by side relation to each other on a shaft for pivotal movement. Latching in a switch closed position is accomplished by a latch bar common to all the push buttons. Each push button carries three movable spring arm contacts, each contact having a pair of tips electrically joined to bridge stationary contacts on a printed circuit board connectable to the switch assembly. Guides are provided to properly position the circuit board so its contacts are aligned with the movable contacts carried by the buttons. A unique contact arrangement including a contact carried by each push button provides for illuminating the button when depressed.