37results about How to "Guaranteed high-quality transmission" patented technology

In an optical transmission system: a first unit generates a first optical supervisory signal being arranged on the shorter-wavelength side of main signals and containing information for determining continuity of an optical transmission line and a second optical supervisory signal arranged on the longer-wavelength side of the main signals and used for supervisory control of optical communication; a second unit generates a wavelength-multiplexed signal by optically multiplexing the main signals and the first and second optical supervisory signals, and transmits the wavelength-multiplexed signal onto the optical transmission line; a third unit receives the wavelength-multiplexed signal, and optically demultiplexes the wavelength-multiplexed signal into the main signals and the first and second optical supervisory signals; and a fourth unit determines whether or not the optical transmission line is optically continuous, based on the first optical supervisory signal, and performs supervisory control of optical communication based on the second optical supervisory signal.

In an optical transmission system, a multiplexer frequency-division-multiplexes a plurality of signals, and outputs the resultant signal to an FM modulator. The FM modulator converts the frequency-division-multiplexed signal into an FM modulated signal through frequency modulation using the frequency-division-multiplexed signal as an original signal. A frequency-divider converts the FM modulated signal into a frequency-divided FM modulated signal whose frequency is ½n (n is an integer of not less than 1) the frequency of the FM modulated signal. An optical modulator has a predetermined input-voltage vs. output-optical-power characteristic, and is biased at the minimum point (voltage) about the output optical power. The optical modulator modulates an unmodulated light fed from a light source with the applied frequency-divided FM modulated signal to produce an optical signal whose optical carrier component is suppressed, and sends the optical signal to an optical transmission line. An optical receiver receives the optical signal, and square-law detects the signal to convert into an FM modulated signal. A FM demodulator demodulates the FM modulated signal to reproduce the original frequency-division-multiplexed signal. This configuration makes it possible to narrow the bandwidth of an FM modulated signal while increasing the frequency deviation thereof, and realize high-quality signal transmission as a result.

A disclosed surface emitting laser is capable of being manufactured easily, having a higher yield and a longer service lifetime. In the surface emitting laser, a selectively-oxidized layer is included as a part of a low refractive index layer of an upper semiconductor distribution Bragg reflector; the low refractive index layer including the selectively-oxidized layer includes two intermediate layers adjoining the selectively-oxidized layer and two low refractive index layers adjoining the intermediate layers. Al content rate in the intermediate layers is lower than that in the selectively-oxidized layer, and Al content rate in the low refractive index layers is lower than that in the selectively-oxidized layer. This configuration enables providing more control over the thickness and oxidation rate of the oxidized layer, thereby enabling reducing the variation of the thickness of the oxidized layer.

A graphic display control system is disclosed. The graphic display control system comprises a server computer comprising a memory unit, a graphic display controller accessing image data displayed on the server computer and a cursor information and thereby storing the image data and the cursor information in the memory unit, a compression engine performing an image compression of the image data displayed on the server computer except a cursor pattern data of the cursor information to generate an compressed image data and thereby storing the compressed image data in the memory unit, a network controller receiving the compressed image data and the cursor information from the memory unit and transmitting the compressed image data and the cursor information through a network, and a remote client computer comprising a memory unit, a network controller receiving the compressed image data and the cursor information through the network and storing the compressed image data and the cursor information in the memory unit of the remote client computer, a decompression engine performing an image decompression of the compressed image data in the memory unit of the remote client computer to generate a decompressed image data and storing the decompressed image data in the memory unit of the remote client computer, a graphic display controller receiving the decompressed image data and displaying the decompressed image data on the remote client computer, and a cursor pattern overlay controller receiving the cursor information and overlaying the cursor information on the decompressed image data.

A reference local oscillation signal transmission station 1 radiates a reference local oscillation signal to a service zone. A portion of the signal received by each radio slave station terminal 2 is branched and fed to an injection locked oscillator 6. As a result, a local oscillation signal which is synchronized with the reference local oscillation signal is obtained. In the slave station terminal 2, the thus-obtained local oscillation signal is fed to a transmission frequency converter (mixer) 7 and a reception frequency converter (mixer) 8. An IF band transmission modulated signal is fed to the mixer 7 for frequency conversion to a radio frequency band, and the thus-obtained radio-frequency modulated signal is transmitted. Meanwhile, a received radio-frequency modulated signal is fed to the mixer 8 for down conversion, and the thus-obtained signal is fed to an IF band demodulator 10 so as to restore an information signal. The present invention not only solves the problem of deterioration of signal quality stemming from phase noise and frequency offset generated in a millimeter wave band oscillator, but also improves the efficiency of frequency use.

High-quality communication using Multicast is realized in wireless communication where re-transmission processing is performed.The present invention includes: a program distribution unit (100) for distributing a program using the Multicast communication; a first communication path (Y1) for transmitting the program distributed from the program distribution unit (100); first communication units (102a, 102b); user terminals (105a to 105h); and a second communication path (103) which is a communication path between the first communication unit (102a, 102b) and the user terminal and is also a wireless communication path where the re-transmission of a frame is performed, wherein the first communication unit (102a or 102b) selects a Multicast frame of a program requested by the user terminal (105a to 105h) from the first communication path (Y1), converts the selected Multicast frame into a Unicast frame, and transmits the converted Unicast frame to the user terminal (105a to 105h).

A transmitting device of the present invention comprises an encoder (20), a transmitting unit (100) including and a pulse generator (30) and a parallel-to-serial converter (50), a transmitting control unit (40), and an a antenna (90) The pulse generator (30) comprises a first pulse train generator (31), a second pulse train generator (32), and an n-th pulse train generator (33) A k-bit information bit train is inputted from the information signal source (10) The encoder (20) encodes the k-bit information bit train into an n-bit encoded bit train at a coded rate of (k / n) The pulse generator (30) generates n-piece repetitive pulse trains corresponding to the n-bit encoded bit train The antenna (90) transmits the n-piece repetitive pulse trains as UWB-IR.

An optical transmission system which permits transmission distance to be prolonged without using repeaters and yet ensures economical, high-quality optical transmission. A branch station performs non-repeated communication with an optical branching point and includes a light pumping section for causing pump light to enter an optical fiber through which a branched, receiving optical signal flows, to perform optical amplification by using the fiber as an amplification medium. An optical branching device includes an optical amplification section and an optical branching section. The optical amplification section redirects the pump light originated from the branch station and propagated through a line to the paired line through which an optical signal transmitted from the branch station flows, to excite an amplification medium inserted in the paired line and doped with active material for optical amplification and thereby amplify power of the optical signal transmitted from the branch station. The optical branching section branches the optical signal transmitted from the branch station and optical signals transmitted from other stations.

In a wireless communication system including a plurality of wireless stations provided in a structure having a radio wave shield arranged at a fixed position, at least one of two wireless stations using an identical wireless channel and two wireless stations using wireless channels adjacent to each other are allocated on both sides of the radio wave shield, respectively. In this case, the structure is an aircraft, and the two wireless stations are allocated on different aisles of the aircraft, respectively. In addition, the two wireless stations are allocated to be apart from each other in a longitudinal direction of the aircraft.

Disclosed is a semiconductor device which performs signal transmission by using inductor coupling. The semiconductor device comprises one or more transmission and reception coil pair, each pair comprising a single transmission coil and a plurality of reception coils, or a plurality of transmission coils and a single reception coil, or a plurality of transmission coils and a plurality of reception coils.

In an optical transmission system: a first unit generates a first optical supervisory signal being arranged on the shorter-wavelength side of main signals and containing information for determining continuity of an optical transmission line and a second optical supervisory signal arranged on the longer-wavelength side of the main signals and used for supervisory control of optical communication; a second unit generates a wavelength-multiplexed signal by optically multiplexing the main signals and the first and second optical supervisory signals, and transmits the wavelength-multiplexed signal onto the optical transmission line; a third unit receives the wavelength-multiplexed signal, and optically demultiplexes the wavelength-multiplexed signal into the main signals and the first and second optical supervisory signals; and a fourth unit determines whether or not the optical transmission line is optically continuous, based on the first optical supervisory signal, and performs supervisory control of optical communication based on the second optical supervisory signal.

A cable for the transmission of signals, includes a plurality of leads, on whose inner conductors an electrically conductive end piece is affixed. At least one of the end pieces includes a first latching element. The cable includes a coupler element, and the coupler element has a body having a longitudinal axis. In addition, the body has parallel feed-throughs, electrically insulated from each other, to accommodate the end pieces. At least one of the feed-throughs includes a second latching element. The end piece is inserted into the feed-through such that the first latching element locks into place with the second latching element. The body furthermore has a first surface and a second surface to guide a mating piece of the coupler element, the first surface having a radially outwardly directed normal vector, and the second surface having a radially inwardly directed normal vector.

The invention discloses an aerospace-used star quad communication cable and a manufacturing method thereof. The aerospace-used star quad communication cable comprises a cable core; and the cable core is sequentially coated with a wrapping layer, a shielding layer and a sheath. The aerospace-used star quad communication cable is characterized in that four core wires are paired and are subjected to star quad with a filling strip as a center to form the cable core; a multi-core inner conductor is wrapped with an insulated layer to manufacture each core wire; the insulated layer has a two-layer structure, the inner insulated layer is a microporous polytetrafluoroethylene thin film, and the outer insulated layer is a polytetrafluoroethylene green tape; the shielding layer has a silver-plated copper wire double-layer braided structure; and both the sheath and the filling strip are made of an ethylene-tetrafluoroethylene copolymer. The aerospace-used star quad communication cable provided by the invention can perform gigabit transmission, and has the advantages of high radiation resistance, high electromagnetic shielding performance, light weight, good flexibility, high temperature resistance, low delay, low attenuation, impact resistance and the like.

The invention discloses a video conference bandwidth management system, and the system is used for obtaining a preset number of continuous raw video frames from a video transmitted by a client; carrying out the compression of the video transmitted by the client according to a preset video compression parameter, and obtaining compressed video frames corresponding to the raw video frames; detecting the current network bandwidth and comparing the current network bandwidth with the data bandwidth of the compressed video; calculating the evaluation value of the image quality of the compressed video when the current network bandwidth is greater than the bandwidth of the compressed video; judging whether the evaluation value of the image quality of the compressed video is within the required range of a preset quality or not; adjusting a video compression parameter when the evaluation value of the image quality of the compressed video is not width in the required range of the preset quality, and carrying out video compression till the evaluation value of the image quality of the compressed video is within the required range of the preset quality. The invention also provides a video conference bandwidth management method. The system and method can achieve the high-definition video image conference, and saves the network bandwidth resource.

This invention provides an optical transmission system which allows to perform high-quality transmission of each of a plurality of signal channels multiplexed. In the optical transmission system, signal light in which a plurality of signal channels with an optical frequency spacing of 400 GHz or more but 12.5 THz or less is transmitted from an optical transmitter to a Raman amplifier through an optical fiber transmission line. In the Raman amplifier, pumping light from a pumping light source unit is supplied to an optical fiber through an optical coupler. The multiplexed signal light inputted to the Raman amplifier arrives at the optical fiber through an optical isolator and optical coupler, and Raman-amplified by the optical fiber. The Raman-amplified multiplexed signal light is outputted from the Raman amplifier through an optical coupler and optical isolator.

In an optical transmission system, an optical terminal transmits a plurality of tone signals corresponding to a plurality of gain bands, where the frequencies of the plurality of tone signals are different from each other, and each of the plurality of tone signals has a characteristic which is varied according to detected power of optical signals in the corresponding gain band. Each optical repeater receives the plurality of tone signals, extracts the characteristics of the plurality of tone signals, and compares a signal representing each characteristic with a reference signal. The optical repeater controls the gains of optical amplification in the plurality of gain bands based on the comparison result so as to equalize the gains in the plurality of gain bands.

The invention provides a computer, an external device thereof and a radio transmission method of service data. The computer comprises a data acquisition module, a first service data processing module,a second service data processing module and a transmission module, wherein the data acquisition module is used for acquiring and processing service data comprising first service data and second service data; the first service data processing module is connected with the data acquisition module and used for generating first protocol data; the second service data processing module is connected withthe data acquisition module and used for generating second protocol data; and the transmission module is respectively connected with the first service data processing module and the second service data processing module and used for transmitting the first protocol data and the second protocol data. The invention ensures the bandwidth for video service data signal transmission based on a radio technology and also ensures the normal working of other service data.

Provided is an optical fiber cable which allows for high-quality signal transmission in short-distance transmission. The optical fiber cable is designed for use in optical communication based on transmitting an optical beam from a light-emitting device, to a light-receiving device. The optical fiber cable has: a proximal end which is one end thereof on the side of the light-emitting device, and a distal end which is the other end thereof on the side of the light-receiving device, wherein an optical beam returning from the side of the distal end toward the side of the light-emitting device has an M2 factor of 1.7 or more; and a length of 50 m or less.

A reference local oscillation signal transmission station 1 radiates a reference local oscillation signal to a service zone. A portion of the signal received by each radio slave station terminal 2 is branched and fed to an injection locked oscillator 6. As a result, a local oscillation signal which is synchronized with the reference local oscillation signal is obtained. In the slave station terminal 2, the thus-obtained local oscillation signal is fed to a transmission frequency converter (mixer) 7 and a reception frequency converter (mixer) 8. An IF band transmission modulated signal is fed to the mixer 7 for frequency conversion to a radio frequency band, and the thus-obtained radio-frequency modulated signal is transmitted. Meanwhile, a received radio-frequency modulated signal is fed to the mixer 8 for down conversion, and the thus-obtained signal is fed to an IF band demodulator 10 so as to restore an information signal. The present invention not only solves the problem of deterioration of signal quality stemming from phase noise and frequency offset generated in a millimeter wave band oscillator, but also improves the efficiency of frequency use.

In an optical transmitter-receiver module for performing optical transmission and reception by using a single-core optical fiber, a light-tight partition plate unit 506 for separation between an optical path of a transmission signal light and an optical path of a reception signal light is held between a jack section 508 for detachably holding an optical plug 240 and a light emitting / receiving unit 505 having an LED 514 and a PD 515 positioned and fixed in place and molded in one piece.

The invention belongs to the technical field of circuit board manufacturing, and particularly relates to a high-precision ultrathin PCB preparation method which comprises the following steps: forminga mask on the surface of a substrate; etching the mask according to a pre-designed printed circuit trend to form a pattern with a concave region and a convex region; injecting a nickel-based metal ionpolyethylene glycol methacrylate resin mixture into the sunken area to form a priming coat; depositing Cu layers on the surface of the priming coat and the convex region; removing the Cu layer located in the convex region and the residual mask; and forming a flat insulating layer to obtain the high-precision ultrathin PCB. Polyethylene glycol methacrylate resin is added to form a mixture with nickel-based metal ions, so that the bonding strength of a priming coat and a base material is improved, the Cu layer is deposited on the priming coat, the bonding strength of the Cu layer and the priming coat is enhanced, the bonding strength of a copper circuit and the base material is finally realized, and the problem of short circuit or open circuit caused by tilting of the copper circuit does not exist. High-quality transmission of PCB signals is ensured.