Abstract: Provided are a method and apparatus using a frequency selective baseband. Symbol-error correction modulation and demodulation is performed by generating a plurality of subgroups by dividing 2N spread codes or orthogonal codes used for frequency spreading into 2M (M<N) spread codes or orthogonal codes; selecting (P+L) subgroups; acquiring P spread codes by inputting M data bits to each of the selected P subgroups to select one spread code among the 2M spread codes of each subgroup; generating L*M parity bits for symbol error correction using P*M data bits inputted to the selected P subgroups; selecting one spread code among the 2M spread codes of the L subgroups by inputting the L*M parity bits to the L subgroups; and selecting the dominant values among the (P+L) spread codes acquired from the (P+L) subgroups to generate transmitting data including the dominant values, where N, M, P, and L are real numbers.

Abstract: 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.

Abstract: Provided are a human body communication apparatus for non-contact communications using a frequency-selective baseband and a human body communication method for non-contact communications in the same. The human body communication apparatus may be useful to perform stable communications between users by reducing interference induced from other communication apparatuses without affecting interference between the users since data are transmitted/received between communication apparatuses adjacent to a human body by spreading and despreading the data using only spreading codes of a limited frequency band (frequency-selective baseband) in which an inductive electromagnetic field formed by an antenna shows the most effective characteristics.

Abstract: A human body communication system is provided. The human body communication system includes a transmitter and a receiver. The transmitter transmits a frame including a preamble, which is a Manchester-encoded pseudo noise (PN) code, to the human body. The receiver receives the frame from the human body, performs Manchester-decoding on the frame, performs cross-correlation on the decoding result and the PN code, and performs frame synchronization using the cross-correlation result. Accordingly, clock and data recovery performance is improved. Efficient frame synchronization with reduced computation amount can be provided.

Abstract: A human body sound transmission apparatus and method for minimizing a signal loss are disclosed. The human body sound transmission apparatus includes: an audio signal transmission unit modulating an audio signal desired to be transmitted, and transmitting the modulated audio signal to the vicinity of a user's ear through the human body (i.e., a user's body); and a carrier wave signal transmission unit transmitting a carrier wave signal for demodulating the modulated audio signal to the vicinity of the user's ear through the air.

Abstract: A frequency selective digital transmission apparatus includes: a preamble transmission processing unit generating a preamble for frame synchronization and spreading the generated preamble with a predetermined spreading code; a header transmission processing unit configuring a header including data attribute information and spreading the header with a predetermined spreading code; a data transmission processing unit performing serial-to-parallel conversion on transmission data according to a selected transmission mode and a spreading scheme and spreading the same with a frequency selective spreading code; and a multiplexing unit multiplexing the preamble, the header, and the data which have been spread by the preamble transmission processing unit, the header transmission processing unit and the data transmission processing unit, respectively, and transmitting the same as digital signals.

Abstract: 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.

Abstract: Provided are a digital communication system using frequency selective baseband and a method thereof. A transmitter of the digital communication system, includes: a preamble/header transmission processing unit for spreading a preamble for frame synchronization and a header including data information; a data transmission processing unit for spreading data by using spread codes having dominant frequency in a desired frequency band, i.e., frequency selective spread codes; and a multiplexer for multiplexing the spreaded preamble and the spreaded header from the preamble/header transmission processing unit and the frequency selective spreaded data from the data transmission processing unit and transmitting the multiplexed signal in digital.

Abstract: Provided is a method of generating and detecting a preamble that may significantly increase accuracy of frame synchronization while avoiding a low frequency domain having great noise power and minimizing hardware complexity and power consumption in a communication system of a digital direct transmission scheme applicable to human body communication. A method of generating a preamble according to an exemplary embodiment of the present disclosure includes: generating a first pseudo noise code and a second pseudo noise code that are different from each other; generating a plurality of same first sub preambles by line-coding the first pseudo noise code; and generating a second sub preamble behind the plurality of first sub preambles by line-coding the second pseudo noise code.

Abstract: 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.

Abstract: There is provided a communication method using a human body as a medium. A modulation apparatus using a frequency selective baseband according to an aspect of the invention may include: a serial-to-parallel conversion unit converting serial data supplied from an upper layer into parallel data consisting of M+1 number of data input bits; and a frequency selective spreader selecting one subgroup among a plurality of subgroups obtained by dividing 2N number (where N is a positive integer) of spreading codes used for frequency spreading by 2M (where M is a positive integer, and M<N is satisfied), and selecting and outputting one spreading code among 2M number of spreading codes of the one subgroup by using the M number of data input bits, and spreading codes obtained by performing bit circular shifts on the 2M number of spreading codes.

Abstract: Provided are a system and method for human body communication using a limited passband. The system includes a transmission frame generating unit for human body communication which generates a transmission frame for human body communication based on data information including user identification (ID) and data scrambled into an orthogonal code generated by the user ID; a symbol mapping unit for symbolizing the generated transmission frame for human body communication according to a predetermined modulating method; a spreading unit for spreading the symbol outputted in the symbol mapping unit; a waveform generating unit for generating a baseband signal whose band is limited to a predetermined range with respect to the data spread in the spreading unit; and a middle band transmitting unit for modulating the baseband signal into a predetermined limited passband signal.

Abstract: There are provided a receiver in human body communication system using multiple receivers reducing an error rate of receiver signals by applying a space diversity acquisition-related SIMO technology to a plurality of received data using multiple receivers or receiver electrodes in a human body communication system using a human body as a medium, and of stably transmitting the data for the interference of signals generated by other users or from different electronic devices, and a method for receiving data in the human body communication system. The receiver and the method for receiving data in a human body communication system may be useful to stably transmit/receive data without any reduction of its transmission rate by reducing the distortion in channels and the signal noise which are caused in the use of one receiver.

Abstract: 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.

Abstract: A communication device and method using the human body are provided. The communication device determines an arrangement direction of signal electrodes and ground electrodes according to a signal transmission direction and whether the ground electrodes come into contact with the human body according to a transmission/receiving distance and then performs data communication with the other communication device connected to the human body for the purpose of efficient human body communication.

Abstract: An adaptive frequency selective baseband communications method using orthogonal codes includes: a communications testing step of performing communications by using one of a plurality of codes each having a different frequency band; a proper code selecting step of selecting a proper code by using a correlation value of a plurality of codes included in test data transmitted in the communications testing step; a communications performing step of performing communications by using the proper code; and a feedback step of newly selecting a proper code by using the correlation value of the plurality of codes included in the test data transmitted in the communications performing step if a pre-set time duration has lapsed or if a reception error of more than a pre-set reference occurs, and performing the communications performing step again, wherein the test data transmitted in the communications testing step and the communications performing step includes a plurality of codes each having a different frequency band.

Abstract: 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.

Abstract: The present invention provides a communication apparatus being in directly contact with a human body and using the human body as a transmission channel for data communication. The communication apparatus attached to the human body transmits a signal in the form of a current, receives a signal transmitted from another communication apparatus attached to the human body therethrough, and eliminates noise included in the received signal. In addition, the communication apparatus compares the noise-eliminated signal and a reference signal and recovers an original signal. Further, the communication apparatus generates a base-band signal and transmits the same through the human body.

Abstract: Provided is an apparatus and method for transmitting a multi millimeter wave, which can minimize signal interference and crosstalk between devices using millimeter waves as transmission frequencies. The apparatus includes a scanner, a physical layer controller and a physical layer. The scanner searches for a peripheral communication environment. The physical layer controller selects a transmission mode from the physical layer based on the peripheral communication environment searched by the scanner. The physical layer has a plurality of transmission modes and outputs a millimeter wave to an outside through an antenna in the transmission mode selected under a control of the physical layer controller.

Abstract: A touch input device includes: a transparent electrode includes: a plurality of unit electrodes; a switch configured to reconfigure an electrical connection state of the transparent electrode; and a controller configured to control the switch that reconfigures the electrical connection state of the transparent electrode.