Abstract:
A communication apparatus which performs a carrier detection and is connected to a transmission line includes: a carrier detecting means for detecting a first control signal for the carrier detection and a second control signal for the carrier detection; a comparing means for comparing carrier detecting results obtained by the carrier detecting means; and a control means for controlling at least one of a symbol length of the first control signal and a symbol length of the second control signal based upon a comparison result obtained by the comparing means.
Abstract:
A diversity circuit uses a plurality of sub-carriers showing CINRs below a lowest threshold, so as to form a sub-carrier group so that combined CINR of the sub-carriers is above the lowest threshold. A diversity tone map generator generates a tope map associated with the lowest primary modulation scheme, based on output from the diversity circuit. A tone map generator generates a tone map associated with primary modulation schemes applied to respective sub-carriers, based on output from the diversity tone map generator.
Abstract:
A method of detecting the existence of an OFDM signal constituted by a plurality of carriers transmitted from another communication apparatus, includes a first selection step of selecting first carriers, where a phase difference between same carriers between symbols adjacent on a time domain is smaller than a predetermined value, from a plurality of carriers of a received signal, a second selection step of selecting second carriers, each of which has a phase of a predetermined relation of the OFDM signal with respect to another carrier, from the selected first carriers, and a carrier "determination step of determining whether the received signal has the symbols of the OFDM signal transmitted from the another communication apparatus on the basis of the selection results of the first and second carriers.
Abstract:
A communication apparatus for transmitting transmission data containing a preamble and a postamble is provided. The communication apparatus includes: a phase vector assigning unit which assigns a first phase vector to a plurality of subcarriers relating to the preamble and assigns a second phase vector to a plurality of subcarriers relating to the postamble, the first phase vector being different from the second phase vector.
Abstract:
A communication apparatus which performs a carrier detection and is connected to a transmission line includes: a carrier detecting means for detecting a first control signal for the carrier detection and a second control signal for the carrier detection; a comparing means for comparing carrier detecting results obtained by the carrier detecting means; and a control means for controlling at least one of a symbol length of the first control signal and a symbol length of the second control signal based upon a comparison result obtained by the comparing means.
Abstract:
A communication apparatus repeatedly outputs a first multi-carrier signal SS during predetermined periods T1, T2, T3,..., and outputs a second multi-carrier signal RS whose phase vector is different from that of the first multi-carrier signal SS, at a predetermined timing based on the first multi-carrier signal SS. The communication apparatus further detects the second multi-carrier signal RS output from another communication apparatus, which uses a different communication method from the communication apparatus. Accordingly, both communication apparatuses can differentiate the first multi-carrier signal SS from the second multi-carrier signal RS without performing relatively cumbersome modulation and other processes.
Abstract:
A communication apparatus repeatedly outputs a first multi-carrier signal SS during predetermined periods T1, T2, T3,..., and outputs a second multi-carrier signal RS whose phase vector is different from that of the first multi-carrier signal SS, at a predetermined timing based on the first multi-carrier signal SS. The communication apparatus further detects the second multi-carrier signal RS output from another communication apparatus, which uses a different communication method from the communication apparatus. Accordingly, both communication apparatuses can differentiate the first multi-carrier signal SS from the second multi-carrier signal RS without performing relatively cumbersome modulation and other processes.
Abstract:
A transmitted digital signal from a digital signal processor is converted into an analog signal at an analog circuit, and then transmitted from transmission lines via a communication transformer. A communication apparatus has a plurality of communication modes that perform communication in different communication ranges. A controller in the digital signal processor changes an output level of the transmitted signal according to the communication modes. More specifically, the controller detects communication quality of the transmitted signal and lowers the output level of the transmitted signal within a range where the detected communication quality does not fall below predetermined quality.
Abstract:
A multicarrier digital transmission signal from digital signal processing unit 1 is converted to an analog signal in analog circuit 2, and is transmitted from transmission lines 61 and 62 via communication transformer 3. Digital signal processing unit 1 includes time carrier detector 12 that detects existence and non-existence of a carrier generated by another apparatus using the transmission line, by using a time waveform of a reception signal and frequency carrier detector 13 that detects existence or non-existence of the carrier by using frequency characteristics of the reception signal. Under the control of the controller 11, carrier detection is performed by switching between activating time carrier detector 12 and frequency carrier detector 13 for operation.
Abstract:
A first communication apparatus 100 transmits a pilot signal which was generated by a pilot signal generation section 14, at predetermined timing, and detects an unbalance component of a transmission line 300 at the time of pilot signal transmission in an unbalance component detection section 13, and controls a transmission signal in such a manner that an unbalance component is reduced by a transmission control section 12 on the basis of the detected unbalance component.