摘要:
Provided are symbol-error-correctable modulation and demodulation methods and apparatuses using a frequency selective baseband. The symbol-error-correctable frequency modulation method using a frequency selective baseband, includes: generating a plurality of subgroups by dividing 2N (N is a real number) spread codes or orthogonal codes used for frequency spreading into 2M (M
摘要:
A method and apparatus for communicating a sound wave is provided. The apparatus includes: a sound wave converter converting a sound wave signal transmitted from a counter apparatus through the human body into an electrical signal when the sound wave is transmitted from the counter apparatus through the human body and converting an electrical signal on data to be output to the counter apparatus into a sound wave; a data processor receiving the converted electrical signal from the sound wave converter and transmitting an electrical signal on the data to be output to the sound wave converter when the data to be output exists; and a switch connected between the sound wave converter and the data processor, the switch transmitting the converted electrical signal to the data processor and transmitting the electrical signal on the data to be output to the sound wave converter. Accordingly, it is possible to efficiently transmit a signal with a low loss of sound wave signal. Thus, it is possible to simply construct communication hardware at a low price.
摘要:
The present invention relates to a powerless electronic notepad and a powerless wireless transmission system using the same, and more particularly, to a powerless electronic notepad that stores data recorded on an electronic notepad using piezoelectric elements and transmits the stored data using a passive RFID tag without the use of a power source, and a powerless wireless transmission system using the same.
摘要:
Disclosed are a method and an apparatus for amplitude modulation of a spread signal that can increase a data transmission rate and frequency use efficiency by loading information on the amplitude of the spread signal used in digital communications. A method for amplitude modulation of a spread signal according to an exemplary embodiment of the present disclosure includes: receiving a first data signal; generating a spread signal by applying a spreading code to the first data signal; receiving a second data signal; and outputting the spread signal at an amplitude corresponding to a value of the second data signal.
摘要:
Disclosed are a crime prevention system using human body communication and a crime prevention method using human body communication capable of actively and effectively preventing a generation of a crime by using human body communication. The crime prevention system using human body communication includes: a monitoring device attached to a monitoring target to sense his physical contact with an observer and providing information obtained by monitoring the monitoring target through human body communication when body contact of the monitoring target with the observer is sensed; and a reception device attached to the observer, receiving the monitoring information through human body communication, and transmitting the monitoring information to a pre-set destination. A criminal act of the monitoring target may be prevented in advance, and when a criminal act is attempted, an observer who may fall a victim of the criminal act can actively cope with the situation.
摘要:
A Time Division Duplex (TDD) communication apparatus and an operation method thereof can provide operation clock signals in the transmission and reception of the TDD communication apparatus using a Clock Recovery & Data Retiming (CDR) circuit, thereby stabilizing an operation without any crystal oscillator and reducing the power consumption. In a transmission time interval, a transmitting frame is processed using a clock signal of a reference frequency generated from the CDR circuit. In a reception time interval, a receiving frame is processed using a clock signal recovered from the receiving frame by the CDR circuit.
摘要:
A receiver in a human communication system includes: receiving electrodes including a transmission frame including control frames and data frames; first and second switches connected with the receiving electrodes; a switching control unit controlling a switching of the first and second switches to selectively connect the receiving electrodes with the first and second switches in response to each control frame according to a predetermined rule every time each of the control frames is input; a signal processing unit performing signal processing on the transmission frame output from the first and second switches; a preamble detection unit detecting the first preamble from each of the control frames included in the signal-processed transmission frame to generate preamble correlation values for the first preamble; and a correlation value processing unit controlling the switching control unit to select pairs of final receiving electrodes among the receiving electrodes based on the preamble correlation values.
摘要:
Provided are an apparatus and method for transmitting sound through a nonlinear medium. The apparatus includes a pre-distorter for previously distorting a sound signal to compensate for distortion to be caused by a frequency characteristic of the nonlinear medium in a transmission process of the sound signal, a sigma-delta modulator for modulating the pre-distorted sound signal into a signal having two signal levels, a high-frequency modulator for multiplying the modulated signal by a carrier wave having a higher frequency than an audio frequency band to shift the modulated signal to a carrier frequency band and generate a high-frequency modulated signal, and a transmitter for converting the high-frequency modulated signal into a sound wave signal suited to be transmitted through the nonlinear medium and transmitting the sound wave signal.
摘要:
A communications device using a near field includes: a near field signal providing unit providing one of a baseband signal and a signal obtained by applying digital modulation to the baseband signal, as a near field signal; an interface unit transmitting and receiving the provided near field signal; and a controller controlling the near field signal providing unit and the interface unit. A low data transfer rate of the related art near field communications can be overcome. Namely, various services can be provided by using a high data transfer rate. In particular, near field communications and a network configuration and data communications performed through the existing wireless network can be implemented as a single combined technique. In addition, power supply and communications can be simultaneously provided effectively by sharing an interface of an electrical coupling and a magnetic coupling.
摘要:
There are provided a human body sound transmission system and a method. The human body sound transmission system according to an aspect of the present invention directly or indirectly contacts a human body to apply coupled signals of high frequency sound signals with high frequency signals, which recover sound signals from the high frequency sound signals, to the human body and transmit the sound signals using the human body as a transmission medium, wherein a magnitude of the sound signals recovered around a human's ear is increased in proportion to the number of signals transmitted through the human body by transmitting the plurality of signals including the same sound signals through the human body.