Abstract: A spread code generation section outputs selectively one of a plurality of different spectral spread codes corresponding to an anti-duplication control signal for indicating the content of the duplication prevention control such as duplication permission, duplication inhibition, and duplication of generation restriction of a video signal in a recording medium. the plurality of spectral spread codes is different in phase or series, or generated by multiplying a specified spread code by the plurality of different orthogonal codes. An additional information signal is spectrally spread using the selected spread code, and superimposed on the video signal to output a combined information signal.

Abstract: An image transmission method, image anti-duplication method, image anti-duplication device, and image recording medium in which information for anti-duplication control is superimposed on a video signal without deterioration of the resultant video signal and the information is extracted accurately and quickly to perform anti-duplication control. An output device starts generation of pseudo-noise (PN) corresponding to a PN code start timing signal generated based on a video sync signal. One chip interval of the PN code is divided into a plurality of divided chips corresponding to a PN code inversion timing signal HT, and an original value of a chip is inverted on an alternate one divided interval to generate a PN inversion code. An anti-duplication control signal is subjected to spectral spreading using the PN inversion code and superimposed on the video signal.

Abstract: The invention intends to reliably the control of duplicating information signals. In the duplication control method according to the invention, a main information signal containing a duplication control information transformed into a spread spectrum signal to be superimposed and a duplication control information superimposed by a processing different from the spectrum spreading is transmitted. The duplication control information transformed into a spread spectrum signal is extracted from the main information signal by reverse spectrum spreading, and the duplication control information superimposed by the different processing is extracted from the main information signal. Information closest to duplication prohibition is selected as an output duplication control information out of the plural extracted duplication control information. On the basis of the selected output duplication control information, the main information signal is controlled on duplication.

Abstract: When an information signal recorded in a magnetic card is updated by an information recording and updating apparatus, a spectrum spread signal corresponding to the updated information signal is generated and it is then recorded superimposed on to the information recorded previously in the magnetic card without erasing the old information. Since the information is spectrum spread, alteration is difficult. Moreover, the magnetic card may be discriminated whether it may be used or not by considering the old information recorded in the magnetic card when it is used.

Abstract: In a telecommunication system a service area is divided into a plurality of cells. Radio base stations are disposed corresponding to individual cells of the plurality of cells. Each radio base station stores regional information such as disaster information, advertisement information, and shopping information. When a communication is made between a radio base station and a portable telephone terminal, regional information such as disaster information, advertisement information, and shopping information is transmitted from the base station to the portable telephone terminal.

Abstract: A mobile radio station radio-communicates with a base station in accordance with a code division multiple access scheme to receive an information provision service from an information service center through the base station. The information service center supplies information data for information service, type data indicating the type of information data, and update data including version data of the information data to the base station. The mobile radio station receives the update data transmitted from the base station and displays the type data on a display, when the desired selected type data is selected from the displayed type data by user's operation, if it is judged that the corresponding information data is the latest information data based on the version data corresponding to the selected type data, receives the information data. When the information data is the latest information data, the information service center charges an account for the reception of information data by the mobile radio station.

Abstract: A playback device 10 generates a PN code with a start timing based on a video sync signal, and generates a pseudo random noise (PN) inverse code which has a reverse polarity to that of the PN code with a timing based on the video sync signal. An anti-duplication control signal is spectrally spread using this PN code, superimposed on the video signal and supplied to a recording device. A PN inverse code which is the same as the PN inverse code used in the playback device is also generated in the recording device based on the video sync signal, and reverse spectral spread is performed using this PN inverse code.

Abstract: In a radio communication system, efficient information provision services is obtained where various information is provided to mobile communication terminal devices separately from call services, update information on information to be provided is transmitted from a base station unit, and a mobile communication terminal device receives the update information and then receives the desired information upon confirming that the desired information has been updated. Consequently, due to the ability to easily determine whether or not the information to be provided has been updated, the mobile communication terminal device need not receive all the information or connect to an information service center, but can efficiently use the information provision services.

Abstract: A synthetic information signal generated by superimposing one spreading code selected out of predetermined plural spectrum spreading codes different in a phase or a code series on a main information signal is output according to a reproduction control signal for controlling the prohibition and the allowance of recording the above main information signal on a recording medium, a reproduction control signal according to the result of detecting the spreading code in the synthetic signal is generated and the main information signal is recorded on the recording medium according to the reproduction control signal.

Abstract: A recording/reproducing method for recording/reproducing digital signals on plural slanted tracks of a tape-shaped recording medium, in which, even if some of the slanted tracks are erased due to junction recording or after-recording, the signals can be reproduced satisfactorily. The input digital signals are divided into upper order bits and lower order bits, and the upper order bits are further divided into upper order side bits and lower order side bits. The data corresponding to the upper order bits, the data corresponding to the upper order side bits of the lower order bits and the data corresponding to the lower order side bits of the lower order bits are recorded in respective different slanted tracks.

Abstract: A searcher for searching paths of signals received from multi-paths, fingers for de-spreading the received signal for searched path and demodulating data, and a combiner for combining output data of the fingers are provided. When demodulated data of fingers is combined by a data combiner, an RSSI combiner detects a signal intensity. Digits of the demodulated data are shifted corresponding to the signal intensity.

Abstract: A code detection apparatus, comprised of a unit for orthogonally detecting a spread spectrum modulated reception signal, a unit for applying phase compensation to the orthogonally detected signal components to produce orthogonal signals (I, Q), a unit for cumulatively adding the phase compensated orthogonal signals (I, Q) a predetermined number of times, a unit for generating square sums (.SIGMA.I).sup.2 +(.SIGMA.Q).sup.2 of the cumulatively added values of the orthogonal signals (I, Q), and a unit for detecting the code of the spread spectrum modulated reception signal based on the generated and output square sums (.SIGMA.I).sup.2 +(.SIGMA.Q).sup.2 obtained by changing the amount of the phase compensation in order to improve detection of synchronization.

Abstract: A spread spectrum communication system, which can detect the synchronization of the spread code surely even when the carrier-to-noise ratio is low, and can detect the boundary of the data. Wherein two types of spread code S20, S21 are transmitted from a transmitter 21 as an initial synchronizing signal based on a predetermined transmission pattern, and two types of spread code are respectively detected at a receiver 22. The predetermined transmission pattern is detected based on the detected two spread codes. Therefore, the spread code is detected several times at the receiver, and the synchronization of the spread code can be detected surely even when the carrier-to-noise ratio is low. Further, the boundary of the data can be detected by the predetermined transmission pattern.

Abstract: First and second radio communication units communicate using the frequency band of an existing microwave transmission system. A judgment whether the first communication unit is within communication range is performed based on information specifying the position of a base station of another radio communication system which is obtained therefrom. If found to be within communication range, the first communication unit shifts to a state and transmits a registration message to the second communication unit, which is then shifted to a transmission state. Interference in the existing microwave transmission system is prevented with a simple construction and without adding a circuit for confirming the present position of a communication unit.

Abstract: A pseudo random noise sequence code generating circuit has a sequence generator (11) for sequentially generating a maximum length linear code sequence at an N-chip cycle and a first to (N-1)th vector multiplier (12 to 14) for obtaining values of skipped portions in the sequence generator by vector multiplication. It does so on the basis of the state value (S1) of a register forming the sequence generator, and generates a successive pseudo random noise sequence code based on an output of the sequence generator (PN1) and outputs of the first to the (N-1)th vector multiplier (PN2 to PN4). Thereby, the operating rate can be reduced to 1/N as compound to the prior art, and the operating voltage and electric power consumption can be reduced.

Abstract: A mobile communication system in which a mobile unit of a mobile communication system operating under the CDMA system may be utilized indoors as a slave unit of the cordless telephone. The communication system operating under the CDMA system includes a plurality of fixed stations 3 connected to a subscriber network and designed to send a PN code shorter in period than a pilot PN code sent from a base station 1, and the identification information for the fixed stations 3, as a control channel, and a mobile unit 2 for receiving the identification information in the control channel received from the fixed station and for making or accepting a call via the fixed station 3 and via the base station 1 if the mobile unit 2 has identified the fixed station to be its own fixed station based on the identification information.

Abstract: In a communication system, the energy of each bit of the inputted information bit string is diffused over the whole frequency band of the orthogonal carriers, and the energy of the plural bits is multiplexed onto each orthogonal carrier, As a result, even though frequency selective fading has occurred attenuation value of the energy of each bit is some remarkable degrading of the error rate can be alleviated, and changing of the data rate can be easily accommodated by modifying the number of the code multiplexing. In this way, a communication system can be realized which is able to alleviate the performance deterioration due to frequency selective fading, and to easily cope with a modification of the data rate.

Abstract: A spread spectrum communication apparatus for communication with a plurality of communication units includes a reception circuit, an automatic gain control circuit, a spread spectrum code detection circuit, and a synthesis circuit. The reception circuit receives signals of a frequency channel inclusive of a target communication unit. The automatic gain control circuit controls the signal intensity of the frequency channel received by the reception circuit to a constant level. The spread spectrum code detection circuit detects the signal intensity of the spread spectrum code of the target communication unit from an output signal of the automatic gain control circuit. The synthesis circuit combines the signal intensity which is based on a gain control signal of the automatic gain control means with a signal intensity as detected by the spread spectrum code detection circuit to find a reception intensity.

Abstract: A communication terminal in which the power consumption in an intermittent reception state can be reduced significantly. The state value of a second spread code generating circuit (62) for a next drive is set in a register (73) to operate a timer (70), and the first and second spread code generating circuit (62, 75) and the receiving circuit are stopped and put in a sleep state. Then, if they are driven again by the timeout of the timer, the receiving circuit is operated and the second spread code generating circuit is operated from the state value which has been set in the register. Further, the intermittent receiving circuit (65) for operating the first spread code generating circuit from an initial state is provided. Therefore, in non-reception, the first and second spread code generating means can be stopped, so that the power consumption in an intermittent state can be reduced significantly.

Abstract: A number of demodulators receive a signal transmitted from a certain base station and propagated via different respective propagation paths. Each demodulator generates a demodulated signal by examining the correlation between the received signal and a pseudo-noise (PN) spread code. A system time managing counter has a count value that is initialized at the timing of the forefront of the spread code in the modulator when at least one of the demodulators starts the demodulating process after power-on or after a reset operation. A signal combiner combines the demodulated signals that are adjusted to coincide in timing with each other from the demodulators at a timing determined by a system time managing counter after initialization and provides a combined demodulated signal.