Abstract: This invention provides a wireless transmitter circuit for mobile communication apparatus and this circuit can be configured with fewer components and is suitable for downsizing. A single PLL synthesizer serves as both RF frequency band PLL and IF frequency band PLL among three oscillators for TX, RX and IF frequency bands, which have been required in conventional mobile communication apparatus. The number of necessary oscillators occupying a large area within a chip is reduced and the number of components is decreased. Specifically, circuitry is arranged to generate local oscillation signals for RF and IF frequency bands by frequency dividing the output of a VCO of the RF frequency band PLL.

Abstract: A method of switching a communication channel when a mobile station moves from one service area to another service area is disclosed. The mobile station determines a difference between the transmission phase of a frame synchronizing signal received from a first base station currently holding a communication channel with the mobile station and the transmission phase of a frame synchronizing signal received from a second base station expected to newly set up a communication channel with the mobile station. The mobile station sends phase difference information representative of the above difference to the first base station via the communication channel. The first base station having received the phase difference information transfers the information to the second base station, causing it to correct the phase of data thereof to be sent to the mobile station. This successfully implements soft handover while guaranteeing the phase synchronization of frames sent from the two base stations.

Abstract: A radio receiver handles a transmitted Walsh sequence having a code length of “m” as a two-dimensional array of “a” rows and “b” columns, and performs a fast Hadamard transform process having a code length of “a” in the row direction. The absolute values of the results are added in the column direction, and a Walsh number having the maximum receiving power is selected to determine a Walsh sequence having a code length of “a.” Then, only the identified column is extracted, and a fast Hadamard transform process having a code length of “b” is applied in the column direction.

Abstract: To simplify the structure of the demodulator and reduce the hardware scale in a code division multiple accessing communication apparatus. A plurality of base band received signals are multiplexed in a time division manner, so that one matched filter executes path searching or a time division multiplexing processing is executed for demodulation in a despreader. Or path searching and demodulation for a plurality of codes are executed with time division multiplexing of outputs from a plurality of code generators.

Abstract: A method of switching a communication channel when a mobile station moves from one service area to another service area is disclosed. The mobile station determines a difference between the transmission phase of a frame synchronizing signal received from a first base station currently holding a communication channel with the mobile station and the transmission phase of a frame synchronizing signal received from a second base station expected to newly set up a communication channel with the mobile station. The mobile station sends phase difference information representative of the above difference to the first base station via the communication channel. The first base station having received the phase difference information transfers the information to the second base station, causing it to correct the phase of data thereof to be sent to the mobile station. This successfully implements soft handover while guaranteeing the phase synchronization of frames sent from the two base stations.

Abstract: A method of switching a communication channel when a mobile station moves from one service area to another service area is disclosed. The mobile station determines a difference between the transmission phase of a frame synchronizing signal received from a first base station currently holding a communication channel with the mobile station and the transmission phase of a frame synchronizing signal received from a second base station expected to newly set up a communication channel with the mobile station. The mobile station sends phase difference information representative of the above difference to the first base station via the communication channel. The first base station having received the phase difference information transfers the information to the second base station, causing it to correct the phase of data thereof to be sent to the mobile station. This successfully implements soft handover while guaranteeing the phase synchronization of frames sent from the two base stations.

Abstract: A method of switching a communication channel when a mobile station moves from one service area to another service area is disclosed. The mobile station determines a difference between the transmission phase of a frame synchronizing signal received from a first base station currently holding a communication channel with the mobile station and the transmission phase of a frame synchronizing signal received from a second base station expected to newly set up a communication channel with the mobile station. The mobile station sends phase difference information representative of the above difference to the first base station via the communication channel. The first base station having received the phase difference information transfers the information to the second base station, causing it to correct the phase of data thereof to be sent to the mobile station. This successfully implements soft handover while guaranteeing the phase synchronization of frames sent from the two base stations.

Abstract: Differences between two adjacent bits of connection control data are derived in sequence. The derived differences are logically combined with a pilot signal and simultaneously with user data. The logically combined signals are spread to spreading bands and added to each other. The added signal is used as a modulating signal and transmitted through phase shift keying (PSK). Thereafter, the PSK modulated carrier is demodulated to derive the modulating signal. The modulating signal is despread to derive a user signal. The user signal includes the user data and the foregoing differences. The modulating signal is further despread to derive the pilot signal with the foregoing differences included. The pilot signal with the foregoing differences is subjected to a conjugate conversion and then multiplied by the user signal so that the foregoing differences are removed from the user signal to obtain the user data. The connection control data is reconstructed from the foregoing differences included in the pilot signal.

Abstract: A spreading code generator generates a spreading code by modulo-two addition of two internal spreading codes. The first internal spreading code is part of a pseudorandom noise sequence, created by resetting a pseudorandom noise generator to an assigned initial state at intervals determined by counting a framing signal. The second spreading code is selected from a set of preferably orthogonal sequences, the selected sequence being repeated at intervals shorter than the period of the framing signal. A code-division multiple-access communication system employs this spreading code generator to generate all spreading codes used at all communicating stations. One of the spreading codes generated at each station is transmitted as a synchronization signal.

Abstract: A transmission device is disclosed in which user data are cross converted, at their base band, by the orthogonal transformers 31.about.34. Signaling data are collected at every integer which does not exceed the ratio of the user data to the signaling data and time division-like multiplexed by the multiplexer 20. The multiplexed data are crossly converted, at its base band, by the orthogonal transformer 35. The base band data cross converted by the orthogonal transformers 31.about.35 are added by the adder 40 and carrier modulated so as to be radio transmitted from the antenna 60.

Abstract: To initiate communication, a first station generates a synchronization signal and sends the synchronization signal to a second station. When the second station detects the synchronization signal, the second station acquires synchronization and sends a synchronization-acquisition message back to the first station. The first station now reduces the power of the synchronization signal, while continuing to send the synchronization signal, and also begins sending a modulated data signal. The second station uses the synchronization signal to maintain synchronization for demodulating the data signal.

Abstract: In a mobile radio communication system, at a transmitter side, when a sound-absent section is detected in sound data, transmission of the sound data is stopped, and instead, tail bits are transmitted. A transmission power is lowered to 0 (zero) or a given value other than 0 when the transmission of the tail bits is finished. The lowering of the transmission power is held until a sound-present section is detected. Convolutional encoding is effected to the sound data and the tail bits prior to transmission. At a receiver side, the variation in transmission power is monitored to control an operation of an associated component in response to the monitored power variation. Viterbi decoding is effected for decoding the convolutional code.

Abstract: There is disclosed a spread code generation device for spread spectrum communication wherein an input data is modulated so as to be spread by a spread code having a first period. The device includes a long period PN code generator for generating a spread code having a second period longer than the first period, an initial state register for storing an initial phase of the spread code having the first period output from the long period PN code generator and for outputting the initial phase to the long period PN code generator, and a counter for receiving and computing the spread code output from the long period PN code generator and for outputting a trigger signal to the initial state register when the computed spread code reaches the first period. The initial state register outputs the initial phase to the long period PN code generation in response to the trigger signal from the counter.

Abstract: In a block-spreading code-division multiple-access communication system a demodulator stores received chip data in a separate memory area for each transmitting station. Each area has a capacity of at least two blocks. When a complete block is received from a transmitting station, all blocks of data stored in the corresponding memory area are correlated against a set of product codewords, which are obtained by spreading a set of orthogonal codewords by the transmitting station's spreading code, to find the codeword that gives the maximum correlation value. For the oldest block, this correlation value and information identifying the codeword are output. For all blocks, the maximum correlation value and corresponding product codeword are used to calculate interference correction data, which are subtracted from the data in other memory areas.

Abstract: A code-division multiple-access spread-spectrum communication system uses pairs of spreading codes with rates of N/2 chips per data symbol to provide a capacity equivalent to that obtained in a conventional system with N chips per symbol. In the transmitter, identical input data are spread in parallel by both spreading codes, then used to modulate two orthogonal carrier signals, and the resulting radio-frequency signals are combined for transmission from an antenna. In the receiver, the received signal is demodulated by parallel multiplication with the two carrier signals, the resulting baseband signals are correlated with the two spreading codes, and the results are added.

Abstract: A demodulator for code-division multiple-access spread-spectrum communications stores received chip data in a separate memory area for each transmitting station. Each area has a capacity of at least two symbols. When a complete symbol is received from a transmitting station, all chip data stored in the corresponding memory area are correlated with the corresponding spreading code, and estimated symbol values are derived from the correlated values. The correlated or estimated value of the oldest symbol is output as a demodulated value. The difference between each estimated symbol value and the previous estimate for the same symbol is multiplied by the spreading code to generate remaining interference values, which are subtracted from all chip data stored in memory areas for other transmitting stations, thereby updating those data.

Abstract: A three-dimensional image generator generates a random signal which it filters in two dimensions generate a realistic three-dimensional image of a natural object such as ocean waves or clouds. By performing the filtering operation repeatedly on overlapping intervals of the random signal, related images can be obtained to generate moving scenes at real-time rates. Two or more partial image generators can be connected in parallel to generate different directions of motion, or different parts of a complex scene. Within each partial image generator, two or more space filters can be connected in parallel to generate superimposed patterns, such as small ripples superimposed on large waves. This image generator is much faster than previous, fractal image generators.

Abstract: A draught beer dispensing system according to the present invention comprises a draught beer receiving receptacle, a beer dispensing valve from which draught beer is dispensed into the receptacle under the pressure of carbon dioxide gases, and a source of supplying the carbon dioxide gases. The beer dispensing valve includes an automatically controlled ball valve. The ball of the ball valve has a through hole. When the ball valve is controlled in a fully open position, draught beer can be dispensed without any foam; while the ball valve is controlled in a partly open position, draught beer can be dispensed with foams whereby to give the almost filled out receptacle some finishing foams.

Abstract: In a method of compressing text data including codewords of characters, an input word each composed of a series of codewords of one or more characters is extracted from the text data, a dictionary containing, as entries, words made up of characters is provided, a codeword is stored in association with each word, occurrence counts of respective words are also stored, the dictionary is searched to find whether or not the input word matches any of the words, the codeword assigned to the word which the input word has been found to match is produced, the occurrence count of the word which the input word has been found to match is updated; and when the input word is not found to match any of the words, the input word is introduced as a new word.

Abstract: A draught beer dispensing system according to the present invention comprises a pressure regulating valve for regulating pressure of carbon dioxide gases supplied from a source of supplying carbon dioxide gases to a draught beer receiving receptacle, a temperature detector provided adjacent to the receiving receptacle to detect a temperature of draught beer within the receiving receptacle, and an arithmetically control device for controlling the pressure regulating valve on the basis of a detected value of the temperature detector, wherein in dispensing the draught beer from the draught beer receiving receptacle, a temperature of the draught beer within the receiving receptacle is detected by the temperature detector, the detected value is inputted into the arithmetically control device, supplied pressure of carbon dioxide gases supplied into the draught beer receiving receptacle is arithmetically operated on the basis of the relationship between beer temperature and pressure stored in advance in the arithmet