An example apparatus includes: an input adapted to receive a signal modulated with data, counter circuitry coupled to the input and operable to determine a first count value in response to a first period between a first rising edge of the signal and a second rising edge of the signal, the first rising edge indicative of a start bit of the data, and determine a second count value based on a second period between a first falling edge of the signal and a second falling edge of the signal, data capture clock circuitry coupled to the counter circuitry and operable to generate a data capture clock based on the first count value in response to the second count value satisfying a threshold, and demodulator circuitry coupled to the counter circuitry and the data capture clock circuitry, the demodulator circuitry operable to generate a demodulated signal based on the data capture clock.

The present disclosure relates to a 5G or pre-5G communication system to be provided for supporting a higher data transfer rate beyond a 4G communication system such as LTE. The present invention relates to a NOMA system based FQAM connection method and an apparatus therefor. The present invention can increase the user transfer rate at a cell boundary. The scheduling method in a wireless communication system, according to an embodiment of the present invention, comprises a step of receiving a signal-to-interference-noise ratio (SINR) value and an alpha value from a terminal; a step of determining, on the basis of the SINR value and the alpha value, a Gaussian SINR value; a step of pairing users on the basis of the Gaussian SINR value; and a step of re-computing MCS on the basis of a re-computed alpha value.

A receiver includes an analog receiver and a digital processor. The analog receiver has an input for receiving a radio frequency (RF) signal, and an output for providing a digital intermediate frequency signal. The digital processor has an input for receiving the digital intermediate frequency signal, and an output for providing digital symbols. The digital processor measures peak-to-peak frequency deviation of the digital intermediate frequency signal, and performs a digital signal processing function on the digital intermediate frequency signal to provide the digital symbols based on the peak-to-peak frequency deviation so measured.

The present disclosure relates to a 5G or pre-5G communication system to be provided for supporting a higher data transmission rate beyond 4G communication systems such as LTE. A method for modulation in a transmitter for transmitting a signal in a wireless communication system according to an embodiment of the present invention comprises: a step for determining a modulation scheme; a step for, if the determined modulation scheme corresponds to a specific modulation scheme, converting encoded information bits to quadrature amplitude modulation (QAM) symbols in accordance with a predetermined QAM modulation order, selecting a sequence corresponding to an element of an integer vector in a predetermined sequence set, repeating the converted QAM symbols for a predetermined sequence length, and outputting signals by multiplying the repeated QAM symbols and the selected sequence; and a step for transmitting the outputted signals to a receiver.

A method and apparatus for modulating/demodulating an FSK signal capable of overcoming a trade-off relationship between a modulation index and a spectral efficiency are disclosed. An apparatus for modulating/demodulating a frequency deviation keying (FSK) signal includes a channel selection-modulator, a phase locked loop, and an output unit. The channel selection-modulator modulates an FSK signal by setting a frequency channel to be used. The phase locked loop generates a desired output frequency ‘fout’ compared to a reference frequency ‘f.sub.REF’ by adjusting a frequency division ratio (N+n) with respect to a frequency of the modulated FSK signal. The output unit amplifies the FSK signal having the generated output frequency ‘fout’ and radiating the amplified FSK signal through an antenna. Here, each of the frequency channels is divided into two or more tones, and different frequency channels are allocated between the tones divided into two or more tones.

A system includes a surface device, preferably positioned on a surface, a downhole device, and a wireline communications system. A downlink communication between the surface device and the downhole device occurs via Hopped Frequency Shift Keying (HFSK) voltage-modulated signals. An optional uplink communication between the downhole device and the surface device may occur via Frequency Shift Keying (FSK) current-modulated signals. The downhole device may comprise an addressable switch.

A device for transmitting a signal according to some embodiments of the present disclosure relates to a device for transmitting a signal using a hybrid waveform. The device may include a modulator configured to modulate an input signal and a signal transmitter configured to transmit the modulated final transmission signal through an LED light source, wherein the modulator is configured to modulate first information into a pulse signal based on frequency shift keying (FSK), and modulate second information into an orthogonal frequency division multiplexing (OFDM) signal, wherein the first information and the second information are different from each other and mix the pulse signal and the OFDM signal into one waveform to generate the final transmission signal.

An optical signal transmission method according to an embodiment of the disclosure is an optical signal transmission method in which a processor performs at least part of each operation, and may include an operation of receiving a data stream, an operation of separating at least part of the data stream into three channels, modulating the separated data streams respectively according to M-ary frequency shift keying (M-FSK) scheme so as to produce an FSK modulated signal, an operation of combining a plurality of FSK modulated signals modulated respectively in the three channels, and producing a color modulated signal according to a bit-color mapping table set in advance, and an operation of transmitting the color modulated signal by controlling a light source of the same optical channel based on the color modulated signal.

Disclosed are techniques to compensate frequency systematic known error (FSKE) in reflector or initiator radios using a hybrid RF-digital approach in multi-carrier phase-based ranging. The hybrid RF-digital approach combines a coarse frequency compensation technique in the RF domain and a fine frequency compensation technique in the digital domain to remove the FSKE across all carrier frequencies from a device. The coarse frequency compensation performed in the RF domain may use a PLL to multiply the crystal frequency to arrive close to a target carrier frequency to compensate for a coarse portion of the known FSKE at the target frequency. The fine frequency compensation may use digital techniques to remove the remaining portion of the known FSKE not compensated by the RF. The hybrid approach reduces the number of fractional bits in the multiplier of the PLL when compared to an approach that uses only the RF-PLL to remove the FSKE.

A method for processing an electrical signal comprises receiving an electrical signal comprising a frequency modulated signal encoding digital data; sampling a first portion of the electrical signal to obtain a plurality of samples to obtain a first sample set; determining an index value from the first sample set by assigning a value to each sample in the first sample set based upon an amplitude of the sample; comparing the determined index value with a plurality of predetermined index values to identify a first output value from a plurality of predetermined output values, each of the predetermined index values corresponding to one of the plurality of predetermined output values; and outputting an indication of the output value. Each of the predetermined output values indicates a respective frequency modulation encoded value and the first output value indicates a frequency modulation encoded value within the first portion of the electrical signal.