Abstract: Errors are reduced when tracing PRNS code delay, especially in receivers operating on signals with rather low code frequency (C/A code) under multibeam effect without deterioration or with minimum deterioration of the signal-to-noise ratio. A method of increasing noise immunity during reception of signals from satellite navigational systems and a device for realizing the same includes radio modules, an analog-to-digital converter, a digital correlation device and digital correlators. A discrimination signal is generated with a variable delay of the signal copy with respect to the exact copy. The use of the correcting sequence of gating digital signals makes it possible to eliminate the multipath effect at a delay of the reflected signal larger than 1.5 d and reduces its negative effect starting from a delay value greater than d/2. In this case, the energy losses compared with a pure mode of the narrow correlator are increased only by 1.76 dB.

Abstract: A system decoder having error correcting memories for high-speed data transmission and a method for controlling the same. A system decoder of an optical disk reproducing apparatus having a descrambler for restoring scrambled data in the process of encoding data, includes first and second memories for correcting an error, and a memory controller for transmitting error-corrected data to the descrambler while data read and demodulated from the optical disk is written in one of the first and second memories, and error-correcting data written in the other memory while the demodulated and error-corrected data is written and read.

Abstract: A high density optical disc having an optical disc protective structure for enabling a high density information recording and retrieval optical disc. The optical disc includes: a first protective film coated by a few tens of microns, on the reading surface of the optical disc, the first protective film having good transmissivity and high hardness against abrasion; and a second protective film coated by a few microns and having a lower surface energy and a minute molecular structure, providing protection against fingerprints on the surface of the first protective film.