摘要:
There is disclosed a radio communication system in which a constitution of a base station and further a control station can be simplified. A radio communication system according to the present invention converts a received signal received by a plurality of antenna elements in a base station to a signal of different frequency band, and then conflates the converted signal in order to generate sub-carrier wave multiplex signal. The signal is converted to an optical signal, and then the optical signal is transmitted to a control station via an optical fiber. Or the control station performs weighting to phase of the transmitted signal transmitted from a plurality of antennas of a base station, and then performs frequency conversion to different frequency band, and then conflates the converted signal in order to generate the sub-carrier wave multiplex signal. The signal is converted to an optical signal, and then an optical signal is transmitted to the base station side via the optical fiber. The control station and the base station divides the received sub-carrier wave multiplex signal by each frequency band, and then the frequency of the divided signals are converted to the same frequency band in order to generate the transmitted/received signal of each antenna element. By such a constitution, it is possible to reduce constituent of the optical transmission components to the minimum and to simplify the constitution of the base station. Furthermore, it is possible to maintain the relative phase difference and the relative intensity of the transmitted/received signal of each antenna element. Because of this, it is possible to estimate an arrival direction of the received signal and to control radiation beam pattern of the transmitted signal.
摘要:
There is disclosed a radio communication system in which a constitution of a base station and further a control station can be simplified. A radio communication system according to the present invention converts a received signal received by a plurality of antenna elements in a base station to a signal of different frequency band, and then conflates the converted signal in order to generate sub-carrier wave multiplex signal. The signal is converted to an optical signal, and then the optical signal is transmitted to a control station via an optical fiber. Or the control station performs weighting to phase of the transmitted signal transmitted from a plurality of antennas of a base station, and then performs frequency conversion to different frequency band, and then conflates the converted signal in order to generate the sub-carrier wave multiplex signal. The signal is converted to an optical signal, and then an optical signal is transmitted to the base station side via the optical fiber. The control station and the base station divides the received sub-carrier wave multiplex signal by each frequency band, and then the frequency of the divided signals are converted to the same frequency band in order to generate the transmitted/received signal of each antenna element. By such a constitution, it is possible to reduce constituent of the optical transmission components to the minimum and to simplify the constitution of the base station. Furthermore, it is possible to maintain the relative phase difference and the relative intensity of the transmitted/received signal of each antenna element. Because of this, it is possible to estimate an arrival direction of the received signal and to control radiation beam pattern of the transmitted signal.
摘要:
There is disclosed a radio communication system in which a constitution of a base station and further a control station can be simplified. A radio communication system according to the present invention converts a received signal received by a plurality of antenna elements in a base station to a signal of different frequency band, and then conflates the converted signal in order to generate sub-carrier wavemultiplex signal. The signal is converted to an optical signal, and then the optical signal is transmitted to a control station via an optical fiber. Or the control station performs weighting to phase of the transmitted signal transmitted from a plurality of antennas of a base station, and then performs frequency conversion to different frequency band, and then conflates the converted signal in order to generate the sub-carrier wave multiplex signal. The signal is converted to an optical signal, and then an optical signal is transmitted to the base station side via the optical fiber. The control station and the base station divides the received sub-carrier wave multiplex signal by each frequency band, and then the frequency of the divided signals are converted to the same frequency band in order to generate the transmitted/received signal of each antenna element. By such a constitution, it is possible to reduce constituent of the optical transmission components to the minimum and to simplify the constitution of the base station. Furthermore, it is possible to maintain the relative phase difference and the relative intensity of the transmitted/received signal of each antenna element. Because of this, it is possible to estimate an arrival direction of the received signal and to control radiation beam pattern of the transmitted signal.
摘要:
A signal transmission device including: a differential signal transmission unit having two output terminals for outputting a differential signal to a paired signal lines including first and second signal lines; a single-ended signal transmission unit having two output terminals for outputting independent two-channel single-ended signals to the paired signal lines; and a filter unit having first and second common mode filters. One terminal of the differential signal transmission unit and one terminal of the single-ended signal transmission unit are connected to the first signal line via one inductor of the first common mode filter of the filter unit. The other one terminal of the differential signal transmission unit and the other one terminal of the single-ended signal transmission unit are connected to the second signal line via one inductor of the second common mode filter of the filter unit.
摘要:
A high-frequency switch module includes a first switching element and a second switching element. A common terminal of the first switching element is connected to an antenna. A common input terminal of the second switching element is connected to a multi-band power amplifier. A second individual output terminal of the second switching element is connected to a fourth individual terminal of the first switching element via a first low-pass filter, and is connected to a third individual terminal of the first switching element via a series circuit including a second low-pass filter and a high-pass filter. A first individual output terminal of the second switching element is connected to a first individual terminal of the first switching element via a phase-shift circuit and a first SAW duplexer, and is connected to a second individual terminal of the first switching element via the phase-shift circuit and a second SAW duplexer.
摘要:
An object of the present invention is to provide a technique to improve the data transmission efficiency which allows correct reception of the data at the same time. A removable memory device that transmits/receives data to and from a host terminal, which includes: a clock reception section that receives a transmission/reception clock, which is used for transmitting/receiving data between the host terminal and the removable memory device, from the host terminal; a phase synchronization pattern generation section that generates a phase synchronization pattern, which is for adjusting a phase of internal reception clock which the host terminal incorporates for receiving data from the removable memory device, based on the transmission/reception clock; and a transmission section that transmits the generated phase synchronization pattern to the host terminal, and in which the phase synchronization pattern includes a first level signal which lasts for at least two cycles, and a second level signal which follows the first level signal and lasts for one cycle, is provided.
摘要:
An object of the present invention is to realize reduction in an area of an output stage driver in an interface circuit that switches between two transmission systems. The interface circuit has two driver circuits and a drive control circuit that can switch between two driving systems that are a voltage driving system and a current driving system. The two driver circuits are connected to a power supply potential via the drive control circuit. Two input signals and inverted logic signals of the input signals are inputted via a selection circuit. According to a control signal inputted into the drive control circuit, the interface circuit switches between the voltage-driving type single-ended transmission system and current driving type differential transmission system.
摘要:
Fine-pitch first and second bonding pads are formed on a chip along its perimeter. The first bonding pads are formed at the peripheral parts on the chip, while the second bonding pads are formed inside the peripheral parts. An ESD protection circuit is connected to the first bonding pad, and an I/O circuit is connected to the second bonding pad. First and second bonding wires connect the first and second bonding pads to the same package pin, respectively. The second bonding wire is configured to be sufficiently longer than the first bonding wire, regardless of the pitch of the first bonding pads.
摘要:
A surface acoustic wave device includes a piezoelectric substrate that does not restore the pyroelectric effect, and a method for manufacturing the same. A surface acoustic wave element housed in a package includes a piezoelectric substrate having a specific resistance in the range of about 1.0×107 Ω·cm to about 1.0×1013 Ω·cm. Pads are electrically connected to an external electrode with a solder. The space between the package and a cap of the package is sealed with a sealing material. At least one of the solder and the sealing material has a melting point of about 300° C. or less.
摘要:
Disclosed are a propylene polymer composition possessing excellent balance among rigidity and low warpage, resistance to deterioration caused by thermal oxidation during processing, weathering resistance, antistatic properties, and low bleeding properties, and a propylene resin composition which can easily produce molded products having excellent balance between rigidity and impact resistance (particularly low-temperature impact resistance) or heat resistance. The propylene polymer composition and the propylene resin composition comprise a propylene block copolymer consisting essentially of the following blocks (a) and (b) and having a melt flow rate of 0.1 to 200 g/10 min: block (a): a polymer block of a homopolymer of propylene or a random copolymer of propylene with a comonomer selected from the group consisting of ethylene and C4-C20 &agr;-olefins, the content of the comonomer being not more than 10% by mole; and block (b): a polymer block of a random copolymer of propylene with at least one comonomer selected from the group consisting of ethylene and C4-C20 &agr;-olefins, the content of the comonomer being 10 to 80% by mole, the average chain length of the comonomer block and the gross average chain length of the comonomer having a relationship represented by formula (I) nb≦n+1.5 (I) wherein nb represents the average chain length of the comonomer block; and n represents the gross average chain length of the comonomer.