Abstract: 1. In a telephone system including a telephone microphone at a subscriber's position, a telephone receiver and circuit connections there-between, contact terminals for said circuit connections and a disconnect switch associated with said contact terminals, subscriber circuit connections leading to the aforesaid connection, means located remote from said subscriber's position for impressing high-frequency energy on said subscriber circuit connections, signal translating means connected with said means effecting capacitative connection through said contacts and disconnect switch with said microphone whereby said microphone operates to modulate said means while said disconnect switch is disconnected from said contacts.

Abstract: In accordance with an illustrative embodiment of the present invention, there is shown a substantially rigid member having interruptions in the longitudinal continuity of the member to provide tortuous paths for the passage of acoustic energy along the member. A plurality of masses are periodically spaced along the interior of the member and are each mechanically integral with opposite sides of the member at locations chosen to enable the member and masses to cooperate as a mechanical filter. By so doing, the structure made of the member and masses will have good acoustic delay and attenuation characteristics as well as good mechanical characteristics.

Abstract: The invention relates to an electromagnetic velocity pickup of the horizol seismometer type, wherein an oscillating mass is elastically suspended as an inverted pendulum with the aid of a deformable system of the articulated parallelogram type. The pickup is characterized in that the suspension comprises rigid beams and at least one elastic pivot.

Abstract: Method and sighting apparatus for aerial bombing from a curved approach path in a plane other than a vertical plane. Computer calculates and drives proper lead angle for sight which includes a reticle for target tracking with freedom to move in two dimensions. Computation, which is based on the relationship of lead angle and rate of turn of the aircraft in a curved flight path through the bomb release point, also considers airspeed, initial distance to target, bombing distance from target, aircraft mass, and can account for wind velocity, bomb characteristics and air density.

Abstract: 1. In a secret telephone transmission system in which speech waves are analyzed into component speech-defining low frequency signals which are coded in stepped wave form, a group of frequency modulators of the same type and same average frequency, means to impress said signals of stepped wave form on the respective frequency modulators to produce a plurality of frequency modulated waves of the same average frequency, and means to translate said last waves into frequency modulated waves accurately positioned at different frequency levels comprising a separate amplitude modulator for shifting the frequency of each such frequency modulated wave, and means to supply to said amplitude modulators carrier waves of accurately spaced frequency comprising a source of base frequency waves of highly constant frequency and a harmonic generator for fixing the frequencies of said supplied carrier waves.

Abstract: The specification discloses a voice scrambler technique wherein a voice signal is split into a plurality of discrete frequency sub-bands. A random code genertor generates a randomized sequence of digital signals. A preselected first portion of each of the digital signals is utiized to control the rearrangement of the order of the frequency sub-bands according to a limited subset of all possible combinations of rearrangements of the frequency sub-bands. The limited subset is chosen to include only the most unintelligible of the possible combinations of rearrangements of the frequency sub-bands. A preselected second portion of each of the digital signals is utilized to control the random inversion of ones of the frequency sub-bands.

Abstract: Receiver of continuous structure adapted to be laid on the ground surface or underground, for seismic prospecting on land, comprising at least one support member for geophones, made of a flexible material having an elongated central portion and two lateral portions defining therewith at least one recess, said geophones being fastened to the central portion of the support member and coupled to the earth therethrough and said lateral portions being provided with longitudinal channels housing conductor cables.

Abstract: Apparatus for effecting and controlling the firing of energy sources, particularly is seismic work, includes means for automatically correcting the delays between the desired and actual firing times which may be different for different sources. These means comprise a number of programmable counters for initiating the firing of different sources, a reference time counter to indicate the desired firing time or times and comparator means responsive to differences between actual and desired firing times to cause the programmable counters to bring the actual firing times towards the desired firing times.

Abstract: 1. In secret telephony, means to analyze speech message waves into slowly varying currents representative of energy variations in respective portions of the speech frequency band, distributor means for rapidly switching fragments of said currents to line in rotation, a source of masing currents for each of said slowly varying currents, the masking currents each varying in magnitude in random manner, and synchronously operating means for adding masking current from a respective source to each fragment of the switched currents.

Abstract: A mass positioned above the earth and having downward extensions, which may include wheels, resting on the earth. One or more closed chambers having two parts vertically reciprocable with respect to each other, one part pressing on the earth, the other part fastened to the underside of the mass. Means to inject pressurized fluid into the chamber to expand the chamber and to lift the mass above the earth, and means to modulate the fluid pressure in the chamber to generate seismic waves in the earth, and means alternately to apply a subatmospheric pressure to the chamber, to collapse the chamber and lift said one part above the earth.

Abstract: A control system for a seismic vibrator, in which the reference, or sweep signal, drives the vibrators directly without the need to control the vibrator so that the seismic signal generated in the earth will be inphase with the reference signal. Instead, the output of one or more sensors on the vibrator are used to generate a "transmitted" signal which is representative of the seismic signal generated in the earth. The transmitted signal is used to phase-shift the reference signal to provide a counterpart signal which is inphase with the transmitted signal. The counterpart signal is used to correlate with the received seismic signal.A plurality of vibrators may be used. They may be grouped together at one point, or they may be spaced apart at independent points. The vibrators may use the same or different reference signals, and may start simultaneously or at delayed times.

Abstract: 1. In a speech privacy transmission system, means for analyzing speech currents into component frequency band currents in a plurality of separate circuits, a corresponding plurality of separate transmission channels, a common keying circuit having an input side and an output side for keying each of said frequency band currents in succession, distributor means for connecting the input side of said keying circuit to each of said plurality of separate circuits in rotation to enable the frequency band currents therein to be keyed in succession, and distributor means for connecting the output side of said keying circuit to each of said plurality of transmission circuits in rotation to enable the keyed currents to be individually transmitted over said respective channels.

Abstract: A conventional type radiation detector in cooperation with a photomultiplier tube provides data pulses of one polarity, corresponding in peak amplitude and number to detected radiation in a borehole traversing an earth formation. Each data pulse is effectively converted to two pulses of different polarities, with one pulse starting when the other is completed and transmitted over a common well logging cable. The creation of a second pulse of an opposite polarity cancels out the low frequency component of the pulse so that they arrive at the surface as a pulse of a single polarity having a very short tail and a fast rise time. This permits more pulses to be transmitted within a given time period than heretofore existed. Surface electronics process the transmitted pulses to provide a record of the sensed condition in the borehole.

Abstract: Method and apparatus for logging the position of a deep borehole filled with liquid in the earth, comprising a long, continuous small diameter pipe adapted to be reeled up on a drum mounted on a vehicle, and means to insert the end of the pipe into the mouth of a borehole and to lower it to any desired depth in the earth. A plurality of geophones are positioned on the surface of the earth in the vicinity of the borehole with conventional amplifying and recording means connected thereto. Means are provided on the vehicle for compressing a liquid or gas, and injecting it into the pipe. On the bottom end of the pipe is a chamber in which this pressurized fluid can be stored. Fast acting valve means are provided which on signal can suddenly open and permit the stored fluid in the chamber to explosively expand into the liquid in the annulus of the borehole.

Abstract: Seismic waves are generated by detonating an explosive gas mixture in an earth cavity formed by driving a short earth auger to a desired depth, leaving most of the augered earth in the hole surrounding the auger shaft, and then pulling the auger and shaft upwardly to lift and compress the augered earth and pack it around the auger shaft, thereby forming and sealing the cavity below the auger. The gas mixture is then introduced through the hollow auger shaft and detonated, preferably by ignition propagation through the connecting hose and the auger shaft. Upon completion of as many gas fills and detonations as may be desired, the auger is reversed and withdrawn, leaving the ground surface virtually undisturbed.

Abstract: 1. In a pulse-producing system, a plurality of space discharge tube ring circuits each comprising a different number of stages, the numbers of stages in the rings having no common factor greater than one, means to cause said rings to step in unison, means to derive output voltage pulses from certain stages of individual rings and spaces from the other stages, and means to combine the outputs of all of said rings in a common utilization circuit.

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. 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.

Abstract: A method of seismic exploration is disclosed wherein an explosive charge is placed in a hole in the ground and wherein a detector is placed in a second hole spaced away from the first hole. The detector is mounted in the bottom of the hole by using an adherent base. The mouth of the hole is sealed to form a quiescent volume in the hole for the detector. Thereafter, the explosive charge is discharged and the output of the detector is recorded.

Abstract: Method for determining the shape of an underground cavity and the location of the interface between two media contained therein by making use of a sonic sonde comprising performing, for each position of the sonde, a series of measurements of the time interval between the transmission of an ultrasonic wave from the sonde and the reception of the corresponding echo after reflection on the wall of the cavity, the selection from said measurements of one of those indicating substantially identical time intervals so as to eliminate the false echos and the determination of the average value of the propagation time of said selected echo for each different location of the sonde and for each direction of the transmitted waves.

Abstract: Pulses of monochromatic coherent sound waves are emitted at an underground test station into a coal seam from several closely juxtaposed sources to form a beam whose reflection at a discontinuity in the seam is detected by a group of receivers. The time lapse between the outgoing and incoming sound pulses is a measure of the distance of the seam boundary from the test station and, upon a controlled shifting of the phases of the outgoing and/or incoming beam components, can be displayed on an oscilloscope screen as a function of sweep angle in an azimuthal and/or an elevational plane.