摘要:
A data embedding device has: a phase adjusting unit for adjusting a phase of an acoustic signal in accordance with a frame unit in which arbitrary transmission data is to be embedded; and a combining unit for embedding the transmission data in the phase-adjusted acoustic signal. A data extraction device has: a removing unit for removing a low frequency component from an acoustic signal in which arbitrary transmission data is embedded, to generate a low-frequency-removed acoustic signal; a synchronizing unit for synchronizing the low-frequency-removed acoustic signal generated by the removing unit, in accordance with a frame unit used when the transmission data was embedded in the acoustic data; and an extraction unit for extracting the transmission data from the low-frequency-removed acoustic signal synchronized by the synchronizing unit.
摘要:
A modulation device including: a modulation unit for modulating a carrier in an audible sound range by an encoded transmission signal to generate a modulated signal; a masker sound generation unit for generating a masker signal outputted as a masker sound for making the modulated signal harder to hear when transmitted with the modulated signal; and an acoustic signal generation unit for inserting the masker signal in the modulated signal to generate an acoustic signal.
摘要:
An OFDM modulation/demodulation method in a transmission system that transmits data from a transmission source to a transmitting destination through OFDM modulation/demodulation is provided, which includes an extension step of extending, by the transmission source, a symbol period by copying an OFDM-modulated symbol in a predetermined place of the OFDM-modulated symbol for a predetermined length; a transmission step of transmitting, by the transmission source, the OFDM-modulated symbol that includes the extended symbol period to the transmitting destination; a demodulation performance step of receiving, by the transmitting destination, the OFDM-modulated symbol from the transmission source and performing OFDM demodulation of the received OFDM-modulated symbol from a plurality of time points; and a selection step of selecting, by the transmitting destination, the demodulation result of the OFDM demodulation to be adopted on the basis of the demodulation results of the OFDM demodulation from the plurality of time points.
摘要:
A data embedding device has: a phase adjusting unit for adjusting a phase of an acoustic signal in accordance with a frame unit in which arbitrary transmission data is to be embedded; and a combining unit for embedding the transmission data in the phase-adjusted acoustic signal. A data extraction device has: a removing unit for removing a low frequency component from an acoustic signal in which arbitrary transmission data is embedded, to generate a low-frequency-removed acoustic signal; a synchronizing unit for synchronizing the low-frequency-removed acoustic signal generated by the removing unit, in accordance with a frame unit used when the transmission data was embedded in the acoustic data; and an extraction unit for extracting the transmission data from the low-frequency-removed acoustic signal synchronized by the synchronizing unit.
摘要:
A modulation device including: a modulation unit for modulating a carrier in an audible sound range by an encoded transmission signal to generate a modulated signal; a masker sound generation unit for generating a masker signal outputted as a masker sound for making the modulated signal harder to hear when transmitted with the modulated signal; and an acoustic signal generation unit for inserting the masker signal in the modulated signal to generate an acoustic signal.
摘要:
When only part of content that is stored inside a terminal is updated, the updated content is allowed to be received efficiently, taking into account reducing the power consumption of the terminal. This broadcast content delivery apparatus (10) has a program information generating apparatus (15) that generates program information including a list of objects constituting the broadcast content, object identifiers, object version number information, and object broadcast times, and a content delivery control apparatus (12) that repeats transmitting the objects based on the object broadcast times, and transmits the program information at a predetermined transmission time, when there is addition, removal or updating with respect to the objects constituting the broadcast content, the program information of the broadcast content is updated, the updating of the objects is reported to a broadcast content receiving apparatus by updating corresponding object version number information, and the addition or removal of the objects is reported to the broadcast content receiving apparatus by updating the object list.
摘要:
Provided is a broadcast supplemental data transmission device, a broadcast supplemental data transmission method, and a broadcast system that can reduce the traffic of a communication network as much as possible at the time of supplementing missing data in broadcasted content data. When “GET HTTP/1.1 If Unmodified Since Time Information”, which is a request for retransmission of missing data containing time information, is received from a receiving device, an HTTP response module determines whether there is rebroadcast of contents containing missing data based on the time information contained in the request for retransmission. When it is determined by the HTTP response module that there is rebroadcast, “412 Precondition Failed”, which is one of error notifications, is transmitted as a response to the receiving device, and the transmission of the contents through a communication network is not performed.
摘要:
A modulation device, a demodulation device, and a transmission system and acoustic signal transmission method using them which can carry out a synchronization process for data signals without using a carrier frequency for a synchronization signal. The modulation device transmits an acoustic signal superposed with a PN sequence set according to a carrier frequency and a data signal. A demodulation device receives the acoustic signal, determines the PN sequence having the highest maximum correlation value with the acoustic signal in a plurality of PN sequences, detects a symbol synchronization point according to the correlation value between the thus determined PN sequence and the acoustic signal, and performs a synchronization process. Thereafter, according to the detected synchronization point and determined PN sequence, an OFDM demodulation processing unit decides the carrier frequency band of the data signal superposed on the acoustic signal and demodulates the data signal.
摘要:
An object of the present invention is to make it possible to appropriately maintain PPP-based communications even in an environment in which the terminal moves and the communication environment continually changes. A mobile communication terminal comprises a plurality of wireless accessing means for establishing PPP-based communication links for respectively different modes of wireless communications with a fixed communication apparatus, which is a communication partner; a PPP device for combining the established communication links; and a valid wireless LAN searching portion for detecting that wireless communication is possible for a wireless LAN adapter. The PPP device executes control so as to establish communication links for the wireless LAN adapter detected as being capable of wireless communication, and for a L2TP virtual device.
摘要:
An object of the present invention is to make it possible to appropriately maintain PPP-based communications even in an environment in which the terminal moves and the communication environment continually changes. A mobile communication terminal comprises a plurality of wireless accessing devices for establishing PPP-based communication links for respectively different modes of wireless communications with a fixed communication apparatus, which is a communication partner; a PPP device for combining the established communication links; and a valid wireless LAN searching portion for detecting that wireless communication is possible for a wireless LAN adapter. The PPP device executes control so as to establish communication links for the wireless LAN adapter detected as being capable of wireless communication, and for a L2TP virtual device.