Abstract: A digital sonar system including a redundant receiver channel is arranged to operate substantially simultaneously in both F.M. and C.W. modes. Upon failure of one receiver channel the system reverts to a single mode or alternate modes on alternate cycles.

Abstract: There is described a digital sonar receiver having a novel beamformer, own doppler nullifier (O.D.N.), and adaptive time varied gain controller. The beamformer interrogates a multi-element transducer by utilizing an interleaved sampling scheme which samples the elements in the transducer array sequentially, in such a fashion that continuous, uniformly spaced samples are obtained. The samples are subsequently converted into digital format, weighed and summed. The O.D.N. eliminates the own ship's doppler effect on the beam output signal resulting in a half beam output signal representative of the target doppler. The O.D.N. offsets the frequency of the beam output signal and a digital generated signal representative of the own ship's doppler. The O.D.N. multiplies these two offsetted signals resulting in a signal lying in each of the sum and difference frequency bands for which the signal lying in the difference frequency band corresponds to the target doppler.

Abstract: There is described a digital sonar receiver having a novel beamformer, own doppler nullifier (O.D.N.), and adaptive time varied gain controller. The beamformer interrogates a multi-element transducer by utilizing an interleaved sampling scheme which samples the elements in the transducers array sequentially, in such a fashion that continuous, uniformly spaced samples are obtained. The samples are subsequently converted into digital format, weighed and summed. The O.D.N. eliminates the own ship's doppler effect on the beam output signal resulting in a half beam output signal representative of the target doppler. The O.D.N. offsets the frequency of the beam output signal and a digital generated signal representative of the own ship's doppler. The O.D.N. multiplies these two offsetted signals resulting in a signal lying in each of the sum and difference frequency bands for which the signal lying in the difference frequency band corresponds to the target doppler.

Abstract: The ability to measure the ratio of vapor versus liquid in a nuclear steam generating system is highly desirable, particularly since, during transient events such as rapid depressurization, the vapor may not be in thermal equilibrium with its liquid and its distribution in the liquid may be highly non-uniform. By using a relatively mono-energetic neutron source such as Californium 252, exposing the medium under investigation to the radiation and using a proton recoil detector as an energy discriminating counter one can estimate the ratio of vapor to liquid by measuring the reduction of flux loss due to scattering when the medium includes vapor as well as liquid.

Abstract: There is described a digital sonar receiver having a novel beamformer, own doppler nullifier (O.D.N.), and adaptive time varied gain controller. The beamformer interrogates a multi-element transducer by utilizing an interleaved sampling scheme which samples the elements in the trandsducer array sequentially, in such a fashion that continuous, uniformly spaced samples are obtained. The samples are subsequently converted into digital format, weighed and summed. The O.D.N. eliminates the own ship's doppler effect on the beam output signal resulting in a half beam output signal representative of the target doppler. The O.D.N. offsets the frequency of the beam output signal and a digital generated signal representative of the own ship's doppler. The O.D.N. multiplies these two offsetted signals resulting in a signal lying in each of the sum and difference frequency bands for which the signal lying in the difference frequency band corresponds to the target doppler.

Abstract: A pattern tracer having provision for recognizing special markings on the pattern termed "command marks" and for recognizing at least two different kinds of commands to enable special control of the machine tool controlled by the pattern tracer.

Abstract: This invention relates to a flexible notch filter for use in a servo system to eliminate natural mechanical resonance. The filter is an improved "twin-T" type where the "in-phase" output of the filter is fed back into the filter. Varying the feedback varies the bandwidth of the filter. The improved filter further provides for attenuation control in addition to control of the center frequency of the filter. The advantage of this filter over prior art designs is that one filter may be manufactured and adapted to be used in many servo systems since the filter can be easily adjusted to effectively eliminate the natural resonating frequency of the machine in addition to reducing phase lag at frequencies below the center frequency of the notch filter.

Abstract: A circular scanning optical pattern tracer produces two impulses per cycle, one impulse in the forward direction and one in the reverse. Means are provided to utilize either one of said impulses selectively to cause the tracer to proceed in a given direction or reverse at will in accordance with the pulse selected.

Abstract: This invention relates to the protection of power transistors in an H configuration power amplifier which drives a D.C. motor. When the amplifier is switched off, it may be possible for the base terminals of the transistors to be turned "on" which results in the transistors conducting. If two series transistors conduct, the resulting short circuit may damage or destroy the transistors. This invention provides an easy and economical apparatus for protecting the transistors in the power amplifier by grounding the base input terminals of the power transistors during all times when the transistors are switched "off.

Abstract: This application relates to circular scanning line tracers or edge tracers and has particular reference to means for producing adjustable lead. In tracing apparatus having a circular scan, the scanner scans in advance of the point of rotation of the tracing mechanism by an amount referred to as the lead. This lead ideally varies depending on the tracing velocity. It is proposed to apply a vari-focal lens to the optics to provide a scanning circle of adjustable diameter to vary the lead.

Abstract: This invention relates to an air flow system for a vacuum cleaner which, because of the nature of the machine, must be able to operate in wet or damp environments without the ingestion of water into the motor. The housing for the motor is of a bulbous shape manufactured of an insulating material and is arranged to have a bulbous shaped insulating cap fitted on the housing in a spaced apart relationship, such that two air flow channels are produced between the housing and cap by a pair of rib structures integrally cast in said housing structure. Air is drawn into the bottom of the cap and moves upwardly between housing and cap, passes through the housing and through the motor fan, through the motor to provide the necessary cooling and thence is expelled to atmosphere by passage out of ports in the housing to pass into another section of the housing-cap structure.

Abstract: This invention relates to an improved method of depositing thin layers of material on a substrate by means of chemical vapor deposition and particularly to addition of gas to the chemical vapor gases, which additional gas reduces conductive heat loss and improves the rate and quality of the coating. The invention has particular application to silicon carbide filaments and their coating with barrier layers of materials, such as hafnium carbide, hafnium nitride, etc., which are useful layers for inhibiting the migration of other materials into the silicon carbide when the silicon carbide filament is used as a reinforcing medium in a composite structure.

Abstract: This invention relates to a vane assembly for a split-shaft gas turbine engine. The invention relates to a vane assembly which is placed in the hot gas stream to control diffusion and to deflect the hot gas just prior to passage through the blades of the power wheel. The vane assembly is characterized by having each controlling and deflecting blade constructed in two cooperating parts, a forward portion of the vane which is hollow and stationary to control diffusion and a trailing portion which is allowed to pivot through a small angle to control deflection. The vane assembly is constructed in sections to have two complete vanes per section and the sections are fitted into circumferential slots in the casing of the turbine. The vane tip actuators are passed through the turbine casing and are fitted to the trailing portions of each vane so that the trailing portions of the entire assembly move as a unit by a single control mechanism.

Abstract: This invention relates to cooling a section of a split shaft gas turbine engine. Because combustion takes place in the region of the shaft-split, overheating may occur and care must be taken to ensure that this portion of the turbine is sufficiently cooled. This invention is concerned with bleeding a portion of the compressed air from an intermediate stage of the compressor turbine and feeding the compressed air into a manifold. Next the air is fed by means of suitable conduit members into the split-shaft region of the turbine. Provision is made to feed this air to the faces of the power disc for the compressor section and the face of the power disc for the output power section of the turbine. Various other parts of the turbine are also cooled in the split shaft region of the turbine.