Surface acoustic wave (SAW) propagations along V/V Waveguides at an angle 30 to Z crystal axis on Y-cut LiNbO₃ were observed by the FTH method, and the results showed the efficient guiding effect of the waveguides. On the multi-moded waveguides, complicated SAW propagation patterns were observed, and were expected to be related to the higher-order-mode excitations. The mode excitations at the entrance of the waveguide were studied theoretically by the method of a modal analysis, and the theoretical propagation patterns on the waveguides were found to be fairly consistent with the observed patterns.

In This paper, the accuracy of the transverse interference method has been raised up by fully correcting a probing ray refraction due to the index gradient of the fiber. A simulation shows that the error is in principle within 0.3% of the index difference between the core center and the cladding. The index profiles of some fibers were practically measured and it was confirmed that this method can be used for a precise, nondestructive, and fast measurement.

This paper describes the orbit utilization increase by virtue of side-lobe reduction in a homogeneous geostationary satellite link. The antenna side-lobe envelope may conveniently by expressed by next two cases: the slope of the side-lobe envelope is enlarged from α to α' (Case ), and the side-lobe level is reduced by a uniform factor of β (Case ). If the total interference noise temperature for the system with equal spacing θ is assumed to be equal to that for the system with shortened spacing owing to the side-lobe reduction, the relationship between orbit utilization increase U and antenna gain function can be obtained by a straight forward way. In this paper, U is given for the cases where side-lobes are reduced at, () earth stations, () satellites, and () earth stations and satellites. Numerical examples are given assuming the orbit spacing θ of 3, earth antenna beamwidth of 0.16, and satellite antenna beamwidth of 1.0. It is quantitatively concluded that the side-lobe reduction is very effective for increasing the orbit utilization.

Some power spectral reshapings of digital coded signals caused by changing the input statistics are treated in this paper. After presenting a power spectral calculation method directly applicable to a Mealy-type encoding automaton, we have shown that it is possible for some transmission codes to have spectral nulls at submultiples of pulse repetition frequency if the set of input sequences are restricted appropriately. The condition for a given transmission code to have such a property is also referred. Secondly, it is proven that discrete line spectra can be generated for some transmission codes if the set of input sequences are properly restricted. As an illustration, we have shown that bipolar coded parity check code sequences produce line spectra, although bipolar coded sequences with independent inputs do not.