摘要:
In the code modulation system for converting input data levels into an output signal in the form of code words by providing M input levels among N input levels assigned to input data with stairlike code weights on the basis of the input levels, (N-M) input levels which are the difference between said N input levels and said M input levels are respectively disposed near transition points where said stairlike code weight is changed, and the code weights are provided with hysteresis in the ascent process and the descent process of the input data level.
摘要:
Parity bits (check bits) having a relatively high redundancy are added to upper significant bits of a digital signal, and parity bits having a relatively low redundancy, are added to the lower significant bits of the digital signal. The signal and the parity bits are recorded on a recording medium. The position of an error in a data block group of the lower bits reproduced from the recording medium is estimated as existing in a block in which the error is detected by the check of the data block group of the upper bits, and in the blocks preceding and subsequent to the former.This error correction method is most suitable for a recording and reproduction system of digital video signals.
摘要:
An improved 8-8 mpping table system in digitally and magnetically recording video signals. Video signals coded into natural binary codes consisting of 8 bits are converted into different binary codes consisting of 8 bits constituted by patterns in which a continuous number of the 1's or the 0's does not exceed a predetermined number. In these codes, the continuous number of the 1's or the 0's is so limited that a maximum magnetization interval is reduced in magnetically recording the signals. Therefore, erroneous code is prevented from occurring in reproducing the signals.
摘要:
The present invention relates to a method and an apparatus for decoding double-encoding codes in which the information to be decoded comprises a first data and a second data. The operation for decoding double-encoding codes is achieved through two stages. A decoder of the first stage checks the first data, and when an error is found in the first data, all symbols of the first data are assumed to be wrong. The first-stage decoder then adds an erasure flag to all symbols to generate erasure symbols. As a result, these erasure symbols include the symbols which are actually erroneous and those which are correct. A decoder of the second stage is used to perform an error correction on the second data. For this purpose, the second-stage decoder detects the number of erasure symbols which are contained in the second data and which are actually erroneous. If the number of actually erroneous symbols does not exceed the maximum number of correctable symbols which can be corrected by the decoder of the second stage, the error correction is effected; otherwise, the decoder detects an error without conducting the error correction.
摘要:
An apparatus for regenerating original signals comprising: means for introducing a first signal that is produced as an original signal passes through a system that cuts off predetermined frequencies; a first circuit means which produces a third signal obtained on an open loop responsive to said first signal and a second signal which is regenerated from a signal of a predetermined frequency that is cut off by said system; and a second circuit means which regenerates the original signal by converting said third signal into a binary signal.
摘要:
An adaptive transform encoder can keep a recording rate of a digital signal at a constant level. It comprises a unit for orthogonal-transforming one block of digital input signal, a unit for calculating an activity index of the orthogonal-transformed block, a unit for comparing the activity index of the block with a predetermined reference, a unit for classifying the block to a standard bit class having a predetermined number of bits when the activity index of the block is equal to the reference, classifying the block to a low bit class having a smaller number of bits than the predetermined number of bits of the standard bit class when the activity index of the block is smaller than the reference, and classifying the block to a high bit class having a larger number of bits than the predetermined number of bits of the standard bit class when the activity index is larger than the reference, a quantization unit for quantizing the input signal of the block with the number of bits designated by the bit class, a unit for selecting the block of the low bit class from the quantized blocks, an allocation unit for adding to the selected block of the low bit class the data having more bits than the number of bits of the standard bit class of the block of the quantized high bit class, and an encoder unit for encoding the quantized block signal.
摘要:
An original digital signal is converted into either a Miller-squared code signal or a Miller code signal, and undergoes serial-to-parallel conversion to produce n-phase signals (where n is desired to be a positive even number). N-phase virtual demodulated signals are simultaneously generated at clock timing having a period equivalent to 1/n times the period of the transmission clock. Out of the n-phase virtual demodulated signals, n/2 phases are selected to undergo parallel-to-serial conversion, the original digital signal being thus obtained.
摘要:
A demodulation circuit for demodulating a modulated digital including a unit for detecting a specific pattern contained in a series of data before modulation, a unit for judging the phase relation between the specific pattern and a clock pulse used for demodulation, a unit for performing a counting operation on the basis of the result of said judgment, and a unit for controlling the phase of said clock pulse for demodulation on the basis of the count.
摘要:
A solid-state color imaging device is provided including a plurality of photosensors which are arrayed in horizontal and vertical directions, and a mosaic color filter made up of filter elements arranged in correspondence with the respective photosensors. The mosaic color filter is arranged such that any group of four adjacent filter elements comprises a first filter which is made for panchromatic transmission, a second filter which is selected from among a first spectral region-transmitting filter, a second spectral region-transmitting filter and a third spectral region-transmitting filter respectively exhibiting different transmission characteristics, and third and fourth filters which are made of complementary color filters which transmit the transmission light component of the second filter and which have transmission components different from each other. The solid-state color imaging device also has means for simultaneously reading out optical signals of two of the photosensors adjacent in the vertical direction, and means for adding the two output signals.
摘要:
An apparatus for recording an reproducing a digital video signal is disclosed which includes n sampling circuits each for performing a sub-Nyquist sampling operation for the digital video signal in such a manner that the amount of data is reduced to one-n-th of an original amount (where n is a positive integer) and a pixel sampled by the sub-Nyquist sampling operation is not sampled by the remaining sampling circuits, recording/reproducing means for recording and reproducing information at all or part of pixels which are sampled by the n sampling circuits and a device for reconstructing the digital video signal from reproduced information at pixels with the aid of a synthesizing technique or interpolation technique.