Abstract: A method of, and apparatus for, transmitting and receiving electrical speech signals transmitted in ciphered form, wherein at the transmitter end there are formed in sections or intervals from the speech signals to be transmitted, by frequency analysis, signal components or parameter signals containing frequency spectrum-, voiced/voiceless information- and fundamental sound pitch coefficients, these signal components are ciphered, the ciphered signal components or parameter signals are transformed into a transmission signal and this transmission signal is transmitted over a transmission channel, and at the receiver end there is reobtained from the transmission signal the ciphered signal components or parameter signals and deciphered, and from the thus-obtained deciphered signal components or parameter signals there is generated by synthesis a speech signal which is similar to the original speech signal.

Abstract: A method of seismic exploration employing a plurality of emission sources and at least one receiver, arranged in a common plane, in which the sources emit signals into the medium to be explored, which are received after reflection by the receiver, the emission times anda received signals being recorded and correlated to yield required information, and in which the relative emission times of the pulse sources is determined by a predetermined program. Apparatus for carrying out this method is also proposed.

Abstract: The invention relates to geophones and/or seismometers utilizing a casing housing a permanent magnet and a coil mass resiliently supported within the casing for movement relative to the permanent magnet along a primary axis, and wherein the mass is movably supported relative to the casing upon diaphragm springs utilizing involute spring elements. Undesirable vibrational responses occurring in the diaphragm springs resulting from orthogonal forces are suppressed by partially filling the void within the casing with a damping fluid wherein the several involute spring elements of a spring are immersed or exposed to the damping fluid in varying degrees to damp resonant narrrow band orthogonal vibrations within the spring elements and permit accurate sensing along the primary axis over wide frequency ranges.

Abstract: An acoustic velocity logging tool employs a transmitter and a pair of receivers. Acoustic pulses from the transmitter pass through the formation surrounding the borehole to the receivers. The received signals, along with control signals, are transferred to an uphole recording system. A record unit operates to apply these receiver and control signals to a magnetic tape recorder. A playback unit transfers the recorded receiver signals to the intensity modulation input of a cathode-ray oscilloscope and, in response to the recorded control signals, applies a trigger pulse to the sweep input of the cathode-ray oscilloscope, successive sweeps of the cathode-ray oscilloscope being intensity modulated alternately by the recorded receiver signals of the pair of receivers. A film recorder makes a continuous film recording of the receiver signals as they appear as variable-density traces on the face of the cathode-ray oscilloscope to provide a continuous two-receiver, variable-density recording.

Abstract: This invention concerns a status alarm for a seismometer group recorder. In using group recorders, the automatic recording feature leaves the field personnel (the user) with minimum confidence that operations are satisfactory, in the absence of a status alarm. An alarm functions when a particular group recorder has been energized and is presumptively ready for operation. The alarm system is actuated only when the major systems within the group recorder are ready to operate. The alarm may be either visual or aural or both.

Abstract: A line correlator for use as a pattern matching device in a high resolution radar system. Binary coded a priori target area information is digitally correlated with binary coded video range trace signals for a plurality of range and azimuth sets in parallel or multiplexed channels (representing an area of interest), the quantitative correlation for each set being stored. Upon determination of the comparatively better correlation coefficient, the associated range and azimuth data set are retrieved and may be employed for terminal guidance purposes.

Abstract: A video tracking system that produces voltages representative of the location of a designated target relative to the tracking axis of a transducer. An error detector unit compares the position of a target, of selected intensity contrast, to that of a tracking gate and updates the gate position to track the target. The error detector unit includes a combination of two integrators coupled in series with two or more gate circuits that are synchronized with the tracking gate. The tracking response characteristic may be selected for optimum performance with expected target profiles by variation of the relative signal gain and timing of the gate circuits.

Abstract: A thermistor material of between 99% and 50% by weight of praseodymium oxide and 1 to 50% by weight of zirconium oxide provides a stable thermistor with desired resistance value changes over a temperature range of 100.degree.C to 600.degree.C. Other selected oxides may be used in place of zirconium. Small amounts of indium or gallium oxides can also be added to the mixture to lower the resistivity and temperature coefficient of resistance.

Abstract: This is a seismic digital recording system for use where the seismic amplifiers are placed near the geophone locations and their outputs transmitted by common cable to the recording truck or recorded on magnetic tape at the geophone location. In such a digital recording system, it is impractical to use a high-speed, high gain-ranging amplifier of 15 or 16 bits range. In our design the gain-ranging amplifier is high-speed but employs fewer bits total range. The extra range is made up in a preamplifier which has a variable range of gain, which can be automatically set, but at slower speed. The invention involves a control system which is responsive to the output of an A/D converter which is connected to the output of the gain-ranging amplifier.

Abstract: A transmitter of acoustic energy which propagates that energy in a directional manner is described. An acoustic signal generator is connected at one end of an acoustic transmission line which exhibits a certain characteristic impedance. The line has a number of ports spaced along its length. Surrounding each port is a coupler section which is antiresonant at the driven frequency and which presents a high acoustic driving point impedance to its associated port. In one embodiment, the interior diameter of the line is changed following each port as to make the acoustic pressure along the line and at each port constant, and the acoustic energy radiated in each coupler equal. Accordingly, acoustic energy is partitioned evenly at each port so as to define an array of equal strength radiators having directional acoustic signal propagating characteristics.

Abstract: The correlator disclosed herein detects in a stream of input pulses a plurality of sequences of time spaced signals, each of the plurality of sequences having a different one of a plurality of pulse repetition intervals disposed within a given pulse repetition interval range. This is accomplished by clocking the input pulses into a first shift register by a first clock pulse having a given frequency. N groups of n bistable stages (N being an integer greater than one and n being an integer greater than zero) are disposed at different spaced time positions along the first register corresponding to the pulse repetition intervals and the pulse repetition interval range. First logic circuitry is coupled to each of the N groups of n stages to provide an output pulse when the time spaced pulses of the plurality of sequences of time spaced pulses are simultaneously present at appropriate ones of the n stages of a given number of the N groups of n stages.

Abstract: A stuff decision code word of multiple bit length is transmitted over a number of frames equal to the number of bits per stuff decision code word. Advantage is made of a unique word used for burst synchronization wherein a common code word is used for both stuff decision and burst synchronization. A hierarchy of bursts is established to identify the particular channel of information to which the stuff decision is associated.

Abstract: An underwater sound imploder adapted for use in the exploration of minerals existing under the sea bed. The imploder consists of three main units, a boiler, a heat shield therefor and a bell shaped sonic device to which the boiler has delivered superheated steam. Expansion of the steam under water pressure causes the implosion. The steam condensate is pumped back into the boiler where it is recycled. The implosions occur repeatedly in the device thereby causing a succession of sonic impulses to pass through the water medium and return as echoes for detection and analysis to determine thereby the character of the reflecting object in the sea bed.

Abstract: An automatic gain control circuit including a wide band digitally controlled amplifier particularly adapted for use with recurring signals. Each of the recurring signals is divided into a large number of discrete time intervals and the gain of the amplifier may be adjusted for each time interval independently of the signal in any other of the time intervals. Transients due to gain modification may be superimposed.

Abstract: 1. In a scrambling system for translating input message values into output currents of substantially random occurrence of values, separate message input circuits for each message value, separate output control circuits for determining each output current value, a plurality of key circuits crossing said message input circuits, means to apply key currents to respective key circuits on a substantially random basis, and means at each cross-over point between said message input circuits and key circuits for setting up a current condition in a corresponding one of said output control circuits to determine the value of output current.

Abstract: 1. In a signaling system for transmitting with secrecy signals of varying amplitude, means to encipher said signals comprising means to produce variable key currents and means to combine said signals with said key currents to produce for transmission combination signal and key currents, and means to modify the variable key current that is sent whenever the signal has zero value.

Abstract: A string of seismic detectors is towed at a certain depth underwater by a survey boat over an area to be explored. A seismic disturbance is produced at a distance below the surface of the water such that the propagation time of seismic waves traveling from the disturbance and reflected from the water surface to the detectors is substantially the same as the propagation time of seismic waves traveling from the disturbance and reflected from the water floor to the detectors. Since the seismic waves reflected from the water surface are out of phase with those reflected from the water floor, the reflected waves tend to cancel or attenuate, thereby eliminating or minimizing these unwanted seismic signals.

Abstract: This invention relates to a land seismic exploration method and apparatus employing a plurality of elongated tubes each having a flexible wall for containing a volume of liquid explosive therein. Each tube is adapted to be detachably connected to either a detonating device for exploding the liquid explosive therein thereby creating a seismic explosion, or to a pressure transducer for monitoring the pressure changes in the liquid explosive caused by the detected seismic pressure waves.

Abstract: A sonic generator sends a collimated acoustical wave into the section of earth under test and resonance conditions are established depending upon the nature and depth of discontinuities in the path of the acoustical wave. These resonance conditions are monitored by observing and recording electrical relationship in the power supply section of the sonic generator.

Abstract: In order to provide for a digital data transmitting system of increased security, means are provided to dynamically alter the synchronous compare character between message transmissions. Included in the data communication system are: a character general for programmatically generating a synchronous compare character; a character storage register for storing the character so generated; and circuitry for moving the synchronous character from the storage register to the data transmission circuitry. By dynamically altering the synchronous character between message transmissions, it is possible to substantially enhance the security of the data transmission system.