A single channel receiver includes an input terminal that receives an analog input signal, a mixer that down-mixes the analog input signal by use of a phase- and/or frequency-corrected oscillator frequency signal and shifts complex-valued information contained in the analog input signal to the real part (or alternatively to the imaginary part) to obtain an intermediate real-valued analog signal, an analog-to-digital-converter that converts the intermediate analog signal into an intermediate digital signal, a demodulator that demodulates the intermediate digital signal into a digital output signal, a phase tracking loop that detects zero-crossings in the intermediate digital signal to obtain phase error information representing a phase error in the intermediate digital signal, and an oscillator that generates the phase- and/or frequency-corrected oscillator frequency signal by compensating the phase and/or frequency error in the intermediate digital signal by correcting the phase of the oscillator frequency signal with the phase error information.

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.

A method includes obtaining a reference signal waveform (b, b.sub.1-b.sub.5) which is defined in accordance with a non-coherent modulation scheme. The method also includes—shaping the reference signal waveform (b, b.sub.1-b.sub.5) to obtain at least one signal waveform (x˜) associated with one or more subcarriers (K) of a plurality of subcarriers (301-303). The method further includes inputting the at least one signal waveform to at least one corresponding channel (1552) of a multi-channel orthogonal frequency division multiplex, OFDM, modulator (F, 1502, 1503, 1504) and transmitting an OFDM symbol (s) output by the OFDM modulator (F, 1502, 1503, 1504).

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.

In an embodiment a device includes a first circuit and a second circuit, wherein the first circuit is configured to generate a fourth signal and a fifth signal by applying the phase shift respectively to a first signal and to a second signal and deliver a sixth signal corresponding to a sampling over one bit of the fourth signal, a seventh signal corresponding to a sampling over one bit of the fifth signal, an eighth signal corresponding to a sampling over one bit of a difference between the fourth and fifth signals, and a ninth signal corresponding to a sampling over one bit of a sum between the fourth and fifth signals, wherein the second circuit is configured to receive the sixth, seventh, eighth, and ninth signals and determine, during a first phase where the first and second signals are representative of a first known symbol of a QPSK constellation, a state of a first bit from among a first state and a second state based on the eighth and ninth signals.

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.

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 system and method of minimizing interference and retries in an environment where two or more network protocols utilize the same frequency spectrum is disclosed. A lower-power network controller is co-located with a WIFI controller. The lower-power network controller listens for a signature that may indicate the presence of a low power protocol packet, such as BLE or Zigbee. The lower-power controller checks for a waveform that is representative of a Zigbee packet prior to generating a request signal to the WIFI controller. This maximizes the likelihood that no WIFI traffic will occur while the incoming packet is being received.

A near-field capacitive data communication system that uses a variable capacitive device such as a PIN diode to change the capacitance of a conductive plate in response to either a high or low data signal. A detector attached to a second conductive plate that is in proximity to the first conductive plate measures the capacitance of the first conductive plate and outputs a corresponding data signal. The technique is wireless, since the two conductive plates are not in electrical contact with one-another, but rather share their static electric fields. A microcontroller can act as a detector by baselining the capacitance of the first conductive plate when its capacitance is in the low capacitance state. The technique is ideal for communication between a pair of toys that can be brought in close proximity to one-another. Since no radio frequencies are used, no special testing or governmental electromagnetic compatibility rules apply.

The present disclosure provides an encoding method and an encoder for a (n, n(n−1), n−1) permutation group code in a communication modulation system, in which 2.sup.k k-length binary information sequences are mapped to 2.sup.k n-length permutation codeword signal points in a n-dimensional modulation constellation Γ.sub.n. The constellation Γ.sub.n with the coset characteristics is formed by selecting 2.sup.k n-length permutation codewords from n(n−1) permutation codewords of a code set P.sub.n,x.sub.i of the (n, n(n−1), n−1) permutation group code based on coset partition. The constellation Γ.sub.n is a coset code in which 2.sup.k.sup.1 cosets are included and each coset includes 2.sup.k.sup.2 permutation codewords, where k=k.sub.1+k.sub.2, and 2.sup.k≤n(n−1). The present disclosure utilizes the coset characteristics to realize one-to-one correspondence mapping of the binary information sequence set to the permutation code constellation, so that the time complexity of executing the encoder is at most the linear complexity of the code length n.