Abstract: A signal shaper generates an output signal representing a binary sequence, the output signal being the time-dependence of a signal value F. The signal shaper is input a first signal value F0 and a different second signal value F1, and receives a sequence of data bits. If the state of a first data bit and the state of a second data bit differ, the signal shaper controls the signal value F to change monotonically from the first signal value F0 or the second signal value F1 at a first point in time via one or more intermediate values at intermediate points in time to the second signal value F1 or the first signal value F0 at a later second point in time. On the time interval from the first point in time to the second point in time, the output signal may be a monotonic step function.

Abstract: A communication circuit is provided which transmits an information bit string from a transmission unit to a reception unit. The transmission unit includes a first modulation circuit that modulates a first carrier wave by a start bit to generate a first frequency signal, a second modulation circuit that modulates a second carrier wave by the information bit string to generate a second frequency signal, and a transmission circuit that transmits the first and second frequency signals from a transmitting antenna. The reception unit includes a reception circuit that receives a signal from the transmission unit, a first detector circuit that detects a signal of the first carrier wave to demodulate the start bit, a second detector circuit that detects a signal of the second carrier wave to demodulate the information bit string, and a detection circuit that is synchronized by the start bit and reads the information bit string.

Abstract: An apparatus for providing a data encoding scheme may include an encoder. The encoder may be configured to determine, for a digital input value comprising a particular number of bits, whether more than half of the bits of the digital input value have a high value. The encoder may be further configured to encode the digital input value by inverting each of the bits of the digital input value in response to a determination that more than half of the bits of the digital input value have the high value. Corresponding method and computer program product, and a decoder and decoding method are also provided.

Abstract: A method of transmitting a control channel format indicator (CCFI), also known as PCFICH (Physical Control Format Indicator Channel), in case where the length of a coded CCFI is not an integer multiple of three, including mapping a plurality of two-bit CCFI into a codebook with each component codeword having three bits; generating a sequence of codewords selected from the codebook by repeating the selected component codeword for predetermined times; generating a codeword by concatenating the sequence of the selected component codewords with the original CCFI bits; and transmitting the codeword carrying information of CCFI. The method further includes a step of generating a permutation of each of the four codewords by assigning K repetitions of the three-bit component codeword to the number of K resource units respectively and mapping remaining K bits of each of the four codewords separately to the number of K resource units.

Abstract: Disclosed herein is a reception apparatus, including an acquisition section adapted to receive a signal which includes at least one of a first signal and a second signal which have different structures from each other except that the first and second signals have a preamble signal and acquire the preamble signal from the received signal; a detection section adapted to detect a value for correcting the signal using the signal; and a correction section adapted to correct, if it is decided based on the preamble signal acquired by the acquisition section that the signal is the first signal, the signal using the value detected by the detection section.

Abstract: The embodiments disclose a method for encoder frequency-shift compensation, including, determining frequency values of an input encoder signal, analyzing an encoder index clock signal and the input encoder signal to determine values of frequency-shifts and compensating for the values of the frequency-shifts to generate a frequency-shift compensated clock.

Abstract: A wireless communication system is provided having a transmitter, having a modulation unit for performing a frequency shift keying modulation wherein an output of the modulation unit is bundled into data blocks. The communication system furthermore comprises a cyclic prefix adding unit for adding a cyclic prefix (CP) into each data block of an output of the modulation unit.

Abstract: A method of transmitting a control channel format indicator (CCFI), also known as PCFICH (Physical Control Format Indicator Channel), in case where the length of a coded CCFI is not an integer multiple of three, including mapping a plurality of two-bit CCFI into a codebook with each component codeword having three bits; generating a sequence of codewords selected from the codebook by repeating the selected component codeword for predetermined times; generating a codeword by concatenating the sequence of the selected component codewords with the original CCFI bits; and transmitting the codeword carrying information of CCFI. The method further includes a step of generating a permutation of each of the four codewords by assigning K repetitions of the three-bit component codeword to the number of K resource units respectively and mapping remaining K bits of each of the four codewords separately to the number of K resource units.

Abstract: The present invention provides a method for communicating data over a voice channel of a wireless communication system. The method includes receiving a first periodic data signal and modulating the first periodic data signal to produce a second periodic data signal. Modulating the first periodic data signal includes inserting a predetermined silence period into the first periodic data signal at timed intervals to produce the second periodic data signal. The method further includes communicating the second periodic data signal over the voice channel of the wireless communication system. The method of modulating the first periodic data signal may include receiving a control signal that includes parameters for a length of the predetermined silence period and timing of the intervals, modulating the first periodic data signal responsive to the received control signal, and producing the second periodic data signal.

Abstract: An FSK signal modulator is provided in a transmitter which receives desired information to be transmitted on its input and which modulates the information to be transmitted to transmit a binary FSK signal. A counter counts a value of addition with the value of addition modified in accordance with a predetermined rule, depending on the value specified by the information to be transmitted, and for holding the counted value . The count value is determined by a threshold value decision circuit with respect to a threshold value. The result from the decision is output in the form of binary FSK signal. An FSK signal modulator will be provided which is simplified in circuit constitution.

Abstract: A communication system for a power line is described. A transmission system of the communication system divides the time axis into a number of time slots synchronized such that one time slot can start about a zero crossing of the power line signal. These time slots may be referred to as channels. Data may initially be modulated into at least one of these time slots over a first transmission period according to a modulation scheme. The time slots and/or modulation scheme used in subsequent transmission periods may be adjusted depending on transmission feedback relating to prior modulated data.

Abstract: A transmitting apparatus groups a data bit sequence to groups each formed of a predetermined number of bits, modulates predetermined bits of one of groups through a frequency shift keying (FSK) modulation method, non-continuously aligns the FSK modulation signals, and transmits the non-continuous FSK modulation signals.

Abstract: Systems and methods for receiving an OFDM preamble without knowledge of channel characteristics are provided. An OFDM preamble signal with frequency shifted cyclic extensions is received. Taken together the cyclic extensions form a frequency shifted version of the OFDM preamble signal. Frequency offsets and timing offsets are estimated and corrected in an efficient manner using a simple concatenation approach in the time domain, followed by a summation of the OFDM preamble signal and the concatenation after a transformation of the OFDM preamble and the concatenation into the frequency domain. Phase errors in the frequency domain are estimated and corrected after FFT transformations of the received signals. A valid preamble is detected and additional parameters for receiving subsequently transmitted OFDM symbols in a channel are extracted from the OFDM preamble. The methods are computationally efficient and robust. Receiver implementations for performing the methods in a DVB receiver are disclosed.

Abstract: An apparatus and method for reducing a Peak-to-Average Power Ratio (PAPR) are provided. The apparatus includes a gain processor for multiplying time signals in paths by gains set for respective paths, a delay processor for delaying gain-multiplied signals in second to last paths except for a first path by time delays set for respective second to last paths, a summer for summing the gain-multiplied signal for the first path received from the gain processor and the delayed signals received from the delay processor, a PAPR processor for measuring a PAPR of the summed signal received from the summer, for comparing the measured PAPR with a target PAPR, and for requesting one or more changes of at least one of the gain and time delay of each path, and a gain delay controller for changing the at least one of the gain and the time delay of each path according to the request received from the PAPR processor and for controlling the gain processor and the delay processor according to the change.

Abstract: An encoder encodes sound data and the like to generate a binary signal. A mapper converts the binary signal into a four-level symbol and outputs the four-level symbol. A base band filter includes a root raised cosine filter and a sinc filter. The base band filter blocks a predetermined frequency component of a symbol to shape the symbol into a waveform signal and outputs the waveform signal shaped. An FM modulator transmits a signal subjected to FM modulation according to a magnitude of an amplitude of a waveform signal to a receiving unit. When a symbol of ±3 is outputted from the mapper, a frequency shift of a signal transmitted from the FM modulator has a predetermined value in a range of ±0.822[kHz] to ±0.952[kHz]. This makes it possible to provide a modulating apparatus, a mobile communication system, a modulating method, and a communication method that use a modulating method that can conform to the FCC rule to be enforced in 2005 without using a linear power amplifier.

Abstract: An apparatus and method for digital up converting in a mobile communication system are provided. The apparatus includes a Selectable Input Logic (SIL), a Scalable Clock Distribution Logic (SCDL), a filter logic, and a mixer logic. The SIL performs decimation at a decimation rate. The SCDL controls a clock frequency. The filter logic performs channel filtering for the decimated signal, and performs interpolation at an interpolation rate variable. The mixer logic up-converts the signal provided from the filter logic.

Abstract: There is an apparatus and technique for generating a sequence of modulated waveforms of finite duration in which the difference in start time of each waveform is shorter than the waveform's overall duration and each waveform in the sequence has independent data modulation imparted upon it. The apparatus consists of a bank of memory cells arranged in an N×M configuration with associated control circuitry, along with an arrangement scheme for the data in the N×M memory cells such that the waveforms will be correctly reproduced when the memory cells are addressed by the control circuitry in the prescribed order.

Abstract: A data communication apparatus using a radio frequency and a data processing method thereof are provided. A first communication apparatus frequency shift keying and phase shift keying modulates and transmits data from a service server to a radio frequency band. A second communication apparatus modulates, demodulates, and outputs the data. The data communication apparatus using a radio frequency, includes: a data modulation module frequency shift keying and phase shift keying modulates data to a radio frequency band to generate a modulated data signal; and a data transmission module transmitting the modulated data to another communication apparatus.

Abstract: A communication device includes a CPU, a wireless LAN communication controller, and a digital cordless communication controller. The wireless LAN communication controller is capable of communicating wirelessly with the access point according to a data communication method. The digital cordless communication controller is also capable of communicating wirelessly with the handset according to a voice communication method. The CPU sets a first frequency band used for wireless communications by the wireless LAN communication controller. The CPU sets a second frequency band used for wireless communications by the digital cordless communication controller. When another communication device interferes with wireless communications between the communication device and the handset, the communication device changes this interference from the other communication device to interference received from wireless communications with the access point by shifting the second frequency band to the first frequency band.

Abstract: An encoder encodes audio data and the like to generate a binary signal. A mapper converts the binary signal into a four-level symbol and outputs the four-level symbol. A base band filter includes a root raised cosine filter and a sinc filter. The base band filter blocks a predetermined frequency component of a symbol to shape the symbol into a waveform signal and outputs the waveform signal shape. An FM modulator transmits a signal subjected to FM modulation according to a magnitude of an amplitude of a waveform signal to a receiving unit. When a symbol of ±3 is outputted from the mapper, a frequency shift of a signal transmitted from the FM modulator has a predetermined value in a range of ±0.822 [kHz] to ±0.952 [kHz]. This makes it possible to provide a modulating apparatus, a mobile communication system, a modulating method, and a communication method that use a modulating method that can conform to the FCC rule to be enforced in 2005 without using a linear power amplifier.

Abstract: The present invention employs hierarchical modulation to simultaneously transmit information on different modulation layers using a carrier RF signal. Initially, first data to be transmitted is assigned to a first modulation layer and second data is assigned to a second modulation layer. In one embodiment of the present invention, the first and second data are assigned based on reliability criteria. The first and second modulation layers are hierarchical modulation layers of the carrier RF signal. Once assigned, the first data is transmitted using the first modulation layer of the carrier RF signal and the second data is transmitted using the second modulation layer of the carrier RF signal. In one embodiment of the present invention, information may be transmitted to one end user using one modulation layer, and information may be transmitted to a different end user using a different modulation layer.

Abstract: Certain embodiments provide a system for recovering data from at least one signal. The system can include an analog-to-digital converter (ADC) and in-phase/quadrature (IQ) generator component that can sample a signal recovered from a communication medium to generate a first signal sample and a second signal sample. A Fast Fourier Transform (FFT) component can process the first signal sample to generate a first signal phase and process the second signal sample to generate a second signal phase. A phase difference calculation component can determine a phase difference between the first signal phase and the second signal phase, determine a bit value represented by the signal based on the phase difference, and output the bit value to an end device coupled to the phase difference calculation component.

Abstract: Certain aspects of a digital baseband transmitter with digital RF/IF support in GSM/GPRS/EDGE compliant devices may comprise receiving digitized data within a chip. A control signal may be generated within the chip indicating whether the received digitized data is to be processed by an IF processing interface or a digital RF processing interface. The baseband processor has the capability to work together with different kinds of RF chips on the market and since this design is implemented on a single module, most of the circuits are shared which reduces the die size significantly. This design also provides a customer more flexibility to choose among different RF vendors.

Abstract: A method of transmitting a control channel format indicator (CCFI), also known as PCFICH (Physical Control Format Indicator Channel), in case where the length of a coded CCFI is not an integer multiple of three, including mapping a plurality of two-bit CCFI into a codebook with each component codeword having three bits; generating a sequence of codewords selected from the codebook by repeating the selected component codeword for predetermined times; generating a codeword by concatenating the sequence of the selected component codewords with the original CCFI bits; and transmitting the codeword carrying information of CCFI. The method further includes a step of generating a permutation of each of the four codewords by assigning K repetitions of the three-bit component codeword to the number of K resource units respectively and mapping remaining K bits of each of the four codewords separately to the number of K resource units.

Abstract: The invention relates to a transmission module for transmitting data in the form of useful digital signals by modulation of a carrier, determined by the useful signals, by means of frequency shift keying. The transmission module contains a PLL circuit with a voltage-controlled oscillator and a controllable frequency divider with a frequency divider control input. The transmission module is designed to induce direct frequency shift keying (DFSK) of the carrier signal by appropriate triggering of the frequency divider with at least two different frequency divider control signals, and it has a modulation data preprocessing unit, which is connected to the frequency divider control input and is designed to weight samples of the same polarity of the useful signals to be transmitted and to fine tune the frequency divider control signal with regard to the frequency deviation to be induced.

Abstract: Improvements are disclosed for in-band signaling, i.e., transmission of data in a voice channel of a digital wireless network during a voice call session. A family of narrow-band signaling methods, some employing tapered waveforms, is disclosed to successfully pass data-carrying signals through the low-bit rate modes of the EVRC-B vocoder commonly used in CDMA wireless channels. These features can be used in cell phones or other wireless communication devices, including automotive applications.

Abstract: A wireless communication transmitter is configured to determine transmitter phase shift, and correspondingly includes a derivation circuit, one or more slope polarity tracking circuits, and a phase shift computation circuit. The derivation circuit derives a reference signal from a signal input to the transmitter and a feedback signal from the transmit signal corresponding to that input signal. So derived, differences in the reference and feedback signals reveal the effect the transmitter has on the transmit signal. Accordingly, the transmitter focuses on differences in the polarities of the reference signal's slope and the feedback signal's slope to determine the effect the transmitter has on the phase of the transmit signal. That is, the slope polarity tracking circuits track the slope polarities of the reference and feedback signals, while the phase shift computation circuit computes the transmitter phase shift as a function of differences in those tracked slope polarities.

Abstract: Method for modulating an RF signal includes the steps of modulating an RF signal using frequency shift keying (FSK) modulation to define a plurality of symbols (2030, 2031). The FSK modulation includes transitioning the modulated signal (204) between at least two different frequencies (f1 and f0) during a guard period (210). The method includes the further step of varying a frequency of the modulated signal 204 during the guard period (210) in accordance with a predetermined rate of change. The predetermined rate of change is selected to minimize a bandwidth of the RF signal.

Abstract: Provided is a digital modulator, including a carrier wave output section that outputs a carrier wave, a variable delay section that delays the carrier wave, and a delay amount setting section that sets a delay amount by which the variable delay section delays the carrier wave based on transmission data being transmitted by the carrier wave. The variable delay section may include a multi-stage delay buffer circuit in which delay buffers that delay an input signal by a unit shift amount are connected in a cascade connection, the multi-stage delay buffer circuit may receive the carrier wave at a first-stage delay buffer as input, and the delay amount setting section may include a multiplexer that selects either an output from the carrier wave output section or an output from each stage of the multi-stage delay buffer circuit.

Abstract: The receiver portion of a UWB wireless device is altered by replacing analog-to-digital circuitry with a simple energy detection circuit. In embodiments of the invention, the coding methodology of a transmitter is altered to support the simplified receiver configuration. For example, instead of coding the data to be sent in the phase of the UWB signal, the data is encoded in a binary fashion in discrete frequency subbands of the UWB signal. Although this may reduce the usable bandwidth of the channel, it also decreases the complexity and power consumption of UWB devices. In another embodiment of the invention, a UWB device is able to select a transmission mode (BPSK or Energy Coding) based on its environment. Moreover, in a further embodiment of the invention, receiving devices may switch between coding modes based on the capabilities of a remote transmitter and/or a peer receiver.

Abstract: A method to communicate information within a data storage system comprising a plurality of enclosures, wherein the method defines and stores a first waveform comprising a frequency FB, a second waveform comprising a frequency F0 wherein that second waveform is decoded to mean a bit comprising a first value, and a third waveform comprising a frequency F1, wherein that third waveform is decoded to mean a bit comprising a second value. The method transmits by an initiating enclosure a byte of data encoded as eight data waveforms, wherein each of those data waveforms comprises the frequency FB in combination with either the frequency F1 or the frequency F0.

Abstract: Improvements are disclosed for in-band signaling, i.e., transmission of data in a voice channel of a digital wireless network during a voice call session. A family of narrow-band signaling methods is disclosed to successfully pass data-carrying signals through the low-bit rate modes of the EVRC-B vocoder commonly used in CDMA wireless channels. Some embodiments generate a tapered signaling waveform in tandem with another waveform using FSK-modulation. These features can be used in cell phones or other wireless communication devices, including automotive applications.

Abstract: An FSK modulator and applications thereof are disclosed. The FSK modulator comprises a phase-locked loop, a frequency divider module, an image rejection mixer and a summing module. The phase-locked loop is operably coupled to generate a first oscillation from a reference oscillation. The frequency divider module is operably coupled to divide the first oscillation to produce a second oscillation. The image-rejection mixer is operably coupled to mix the second oscillation with a low intermediate oscillation to produce a mixed data signal, and the summing module is operably coupled to sum the mixed data signal with the first oscillation to produce an FSK modulated signal.

Abstract: An FSK signal modulator is provided in a transmitter which receives desired information to be transmitted on its input and which modulates the information to be transmitted to transmit a binary FSK signal. A counter counts a value of addition with the value of addition modified in accordance with a predetermined rule, depending on the value specified by the information to be transmitted, and for holding the counted value . The count value is determined by a threshold value decision circuit with respect to a threshold value. The result from the decision is output in the form of binary FSK signal. An FSK signal modulator will be provided which is simplified in circuit constitution.

Abstract: A method is disclosed for transmission of commands or command combinations via a communication link by coded frequency-shift keying. Each command or command combination is associated with one frequency pair. When a command changes from a preceding command or command combination to a subsequent command or command combination, one frequency (which will be the first to be transmitted) in the frequency pair of the subsequent command or command combination is chosen as a function of at least one other associated frequency pair.

Abstract: A Gaussian Frequency Shift Keying/Frequency Shift Keying (GFSK/FSK) modulation circuit implemented in a digital manner comprises a frequency divider for dividing frequency of an inputted clock signal to get a sampling signal, a buffer coupled to the frequency divider for storing inputted data, an integrator coupled to the buffer for processing integration according to the data outputted from the buffer, a first read only memory coupled to the integrator for transferring the data outputted from the integrator according to a cosine function, and a second read only memory coupled to the integrator for transferring the data outputted from the integrator according to a sine function.

Abstract: Disclosed is an SSC controller that exercises control to supply a control signal to a phase interpolator which receives an input clock signal and varies the phase of an output clock signal in accordance with the control signal, and to frequency-modulate the output clock signal. In an SSC controller, a counting operation control circuit outputs a counting operation control signal that controls count enable and disable. A p-counter receives a frequency-divided clock signal from a frequency divider and counts the signal when the counting operation control signal from the counting operation control circuit indicates count enable. Upon counting up to a predetermined first value, the counting operation control circuit generates a first output signal and sets its count value to zero. When the counting operation control signal indicates count disable, the p-counter stops counting.

Abstract: According to the invention, a very narrow-band transfer signal (LS) is generated by serially connecting a frequency modulator (2) and an amplitude modulator (4). The frequency modulator (2) is operated at a modulation index which at least largely suppresses the carrier signal (TS) while the amplitude modulator (4) suppresses the broadband portion of the spectrum by fading out the transfer signal (LS) during frequency-shift keying.

Abstract: An FSK signal modulator is provided in a transmitter which receives desired information to be transmitted on its input and which modulates the information to be transmitted to transmit a binary FSK signal. A counter counts a value of addition with the value of addition modified in accordance with a predetermined rule, depending on the value specified by the information to be transmitted, and for holding the counted value. The count value is determined by a threshold value decision circuit with respect to a threshold value. The result from the decision is output in the form of binary FSK signal. An FSK signal modulator will be provided which is simplified in circuit constitution.

Abstract: A frequency shift keying (FSK) demodulator includes a band-pass filter, an auto-calibration loop, a phase comparator, and an analog-to-digital converter. The band-pass filter is used for shifting phase of an FSK signal to generate a revised FSK signal. The auto-calibration loop is coupled to the band-pass filter for adjusting a center frequency of the band-pass filter. The first input end of the phase comparator is coupled to an output end of the band-pass filter, and the second input end of the phase comparator is used for receiving the FSK signal. The phase comparator is used for comparing the FSK signal with the revised FSK signal and outputting a comparison result. The analog-to-digital converter is coupled to the phase comparator for converting the results of the phase comparator into digital data. Similarly, a frequency modulation (FM) demodulator includes a band-pass filter, an auto-calibration loop, and a phase comparator.

Abstract: A communication system is provided which implements a method for up-converting a baseband signal to a given number of frequency bands that together define a signal transmission channel. A sequential order is defined in which the frequency bands are to be used for up-converting the baseband signal, and up-converting the baseband signal to one frequency band after the other in the defined sequential order such that the spectral distance between two frequency bands is equal or higher for the frequency bands being direct neighbors in the defined sequential order than being direct neighbors in the spectral order.

Abstract: The present invention provides a structure in which an amplitude-modulation mode and a frequency-modulation mode are switched.

Abstract: When no messages exist which must be notified to a mobile transmitting/receiving apparatus (102), a carrier signal of non-modulation is outputted in an area of control information of transport data having a frame structure. As a specific example, an FSK modulator (16) causes a carrier signal of non-modulation to be outputted by a transmitting circuit (17) from a line control apparatus (101) in correspondence with the area for control information in which non-modulation data is set by a frame data processing unit (15), while causing a modulated wave signal as four-level FSK modulated to be outputted in the areas other than the non-modulation data area. When non-modulation data is set in the area for control information, function channel identification information in the same frame is set as non-modulation identification data, thereby allowing any unstable operation in the mobile transmitting/receiving apparatus (102) on the receiving side to be avoided.

Abstract: A tire pressure monitoring system is capable of ensuring accuracy of the rate of transmission of data via wireless communications without an increase in the number of oscillators and an increase in the cost. The tire pressure monitoring system includes a tire pressure measuring module. The tire pressure measuring module has a microcomputer, an activation control circuit, a pressure sensor, a temperature sensor, a frequency divider, a transmitting circuit, and a battery. The microcomputer has a clock pulse generator, analog-to-digital converter circuits and a controller. The transmitting circuit has an oscillator circuit. The frequency divider divides the frequency of a carrier wave CW output from the oscillator circuit to generate a clock signal, and outputs the clock signal to the controller included in the microcomputer. The clock signal is used for the timing for outputting data to a data signal line DL.

Abstract: A method for transmitting and receiving a signal and an apparatus for transmitting and receiving a signal are disclosed. The method for receiving the signal includes receiving (S210) the signal in a first frequency band, identifying (S220) a first pilot signal including, a cyclic prefix obtained by frequency-shifting a first portion of an useful portion of the first pilot signal and a cyclic suffix obtained by frequency-shifting a second portion of the useful portion of the first pilot signal from the received signal, demodulating (S220) a signal frame including a physical layer pipe (PLP) to which a service stream is converted, by an orthogonal frequency division multiplexing (OFDM) scheme, using information set in the first pilot signal, parsing (S230) the signal frame and obtaining the PLP and obtaining (S240) the service stream from the PLP.

Abstract: An encoder in a transmitter uses space-time trellis coding. An input bitstream is multiplexed to produce in parallel a set of output bitstreams. A multiplier applies a code generating weight to each output bitstream, which are combined, mapped and transmitted by a single antenna.

Abstract: A frequency-shift keying (FSK) signal detector includes a binarizing circuit for receiving an FSK signal and expressing amplitude of the FSK signal in binary; a correlator for receiving the FSK signal expressed in binary and acquiring a correlation of the FSK signal; and an arithmetic unit for performing an arithmetic operation on the output of the correlator to detect and output the FSK signal. The correlator includes plural stages of shift register for sequentially shifting the FSK signal in response to a clock signal; a correlation filter for obtaining the correlation by a correlation signal sequence and a window function signal sequence which obtain a correlation value at one of two frequency components generated by frequency-shift keying; and another correlation filter for obtaining the correlation by a correlation signal sequence and a window function signal sequence which obtain a correlation value at the other of the two frequency components.

Abstract: When a sound presence/absence detector (12) detects a sound absence interval, a non-modulated carrier signal is outputted in an area used to transmit speech data that are included in transmission data having a frame structure and that correspond to the sound absence interval. That is, an FSK modulator (14) causes a transmitting circuit (15) to output the non-modulated carrier signal from a wireless communication apparatus (100) in the area used to transmit the speech data corresponding to the sound absence interval. In the meantime, a four-level FSK modulated wave signal is outputted in the areas other than the one of the sound absence interval. A non-modulation discriminating data for allowing the sound absence interval to be determined are included in an area of channel identifying information included in the transmission data having the frame structure, and allow a communication terminal apparatus at the receiving end to avoid any unstable operations.

Abstract: A method for transmitting a signal by a transmitter in a frequency overlay communication system. The method includes generating y first signal groups by shuffling input information data with a length yN on an N-by-N grouping basis according to a first shuffling scheme; generating y second signal groups by performing N-point IFFT on each of the first signal groups; generating y third signal groups by multiplying each of the second signal groups by preset values; generating N fourth signal groups by de-shuffling the third signal groups on a y-by-y grouping basis according to a de-shuffling scheme; generating N fifth signal groups by performing y-point IDFT on each of the fourth signal groups; generating y sixth signal groups by shuffling the fifth signal groups according to a second shuffling scheme, and serial-converting the sixth signal groups; and performing a transmission RF process on the serial-converted signal and transmitting the RF-processed signal to a receiver.

Abstract: A method, system and digital modulator for modulation are provided The modulator includes a dividing mechanism for dividing a reference clock by a divide value to produce a modulated signal associated with at least one input data, and a control unit for providing at least one divide sequence to the dividing mechanism. The at least one divide sequence includes a sequence of one or more divide values. The divide value of the divide sequence is configurable and selectively provided to the dividing mechanism based on the at least one input data. The method includes configuring at least one divide sequence including a sequence of one or more divide values, and selecting a divide value from the at least one divide sequence based on at least one input data. The method includes dividing a reference clock by the selected divide value and generating a modulated signal based on the divide operation.