A signal generating circuit includes a control voltage setting unit (CVSU) configured to set a control voltage for a chirp signal using voltage-frequency characteristics indicating characteristics of an output frequency versus voltage; a VCO configured to alter the frequency of its output signal by the control voltage; a quadrature demodulator configured to perform quadrature demodulation of the output signal of the VCO to generate an inphase signal and a quadrature signal orthogonal to each other; and a frequency detector configured to detect the frequency of the output signal of the VCO on the basis of the inphase signal and quadrature signal. The CVSU corrects the control voltage by using the voltage-frequency characteristics derived from relationships between the control voltage and the frequency of the output signal of the VCO. The VCO generates the chirp signal based on the control voltage corrected by the CVSU.

Advanced modulation and demodulation schemes for LoRa or equivalent chirp spread spectrum transmissions, with differential modulation and symbol repetition improve the sensitivity in combination with soft demodulation methods.

Transmitter for chirp-modulated radio signals comprising a chirp generator configured to generate a series of chirp signals, wherein each chirp carries an element of information encoded as a cyclic shift, and has a phase encoding an error correction code dependent form the cyclic shift of the chirp, the transmitter further comprising a modulator configured to modulate the series of chirp onto a radio signal and a radio transmitter, transmitting the radio signal. receiver for chirp-modulated radio signals, comprising a clock unit and a demodulator configured for demodulating a series of received chirps signal, the demodulator having a dechirp unit, configured for determining a cyclic shift of each received chirp relative to a base chirp and an error correction code based on a phase of the received chirp, the receiver having a synchronism correction unit configured to detect and/or correct an error in the clock unit based on the error correction code.

Systems for communicating data through a satellite are disclosed. The systems generally include a radio designed for terrestrial communications that is configured to uplink data to one or more satellites. The one or more satellites are configured to receive the data from the terrestrial radio. In addition, the systems include terrestrial receivers, such as one or more chirp spread spectrum radios, positioned at ground level, which are configured to receive the data from the one or more satellites.

The communication process for high-sensitivity and synchronous demodulation signals between a transmitter (2) and a receiver (3) comprises a first synchronisation phase followed by a modulation and demodulation phase of the data. To achieve this, the transmitter transmits a pseudo-periodic chirp signal to the receiver, where a frequency conversion of the chirp signal is performed in a mixer (33) by an oscillating signal (So) at constant frequency of a local oscillator (34) to supply an intermediate signal, which is filtered and sampled for a logic unit (37). An assembly (38) of m pairs DFT blocks phase-shifted in relation to one another and operating in parallel is provided in the logic unit. A processing unit (39) receives the result of the pairs of the assembly to determine frequency and phase errors between the transmitter and the receiver on the basis of two peaks detected by one of the pairs above a threshold to synchronise the receiver.

Systems, methods, and circuitries are provided to measure a swept error power ratio (SWEEPR) of a device under test. A method includes generating a time-variant stopband test signal having a time-variant stopband and determining an error of the device under test based on an output signal generated by the device under test in response to the time-variant stopband test signal.

Devices and methods for enhancing forward error correction techniques for communications using chirp spread spectrum are disclosed. The method includes receiving a chirp signal having a plurality of chirps, identifying an N bit column that has an uncorrectable bit error, skipping the identified N bit column, decoding each remaining N bit column within the M×N matrix based on an error correction code and N−Q parity bits, decoding each M bit row within the M×N matrix based on the error correction code and M−D parity bits, determining that the uncorrectable error bit in the identified N bit column is remedied as a result of the decoding, and decoding the identified N bit column based on an error correction code and N−Q parity bits.

A chirp spread spectrum (CSS) receiver may reject, based on multiple data alignment chirps that includes an attribute identifier that is a mismatch to one or more preconfigured identifiers, a message early and before fully receiving/decoding the message. The multiple data alignment chirps may enable usage of a larger range of IDs than a single chirp signal. A receiver may receive a sequence of training chirps for symbol alignment followed by multiple opposite chirps for data alignment. Training chirps may be processed through a fast-Fourier transform (FFT) and the resulting values accumulated until a threshold is exceeded. Using symbol alignment from the training chirps, the receiver may decode multiple opposite chirps that indicate data alignment and comprise an encoded identifier. The receiver may reject the message and terminate further message processing based on the encoded identifier being a mismatch to preconfigured identifiers or attributes indicated by the encoded identifier.

Systems, devices and methods for enhancing error correction decoding for communications using chirp spread spectrum are disclosed. A chirp signal having a plurality of chirps is received, a codeword is identified based on at least one of the plurality of chirps, a received signal strength indicator (RSSI) associated with at least a portion of the codeword is identified, at least one decoding threshold is adjusted based on the identified RSSI, and the codeword is decoded using the adjusted at least one decoding threshold.

A chirp spread spectrum (CSS) receiver may reject, based on a data alignment chirp that includes an identifier that is a mismatch to a preconfigured identifier, a message early and before fully receiving/decoding the message. A receiver may receive a sequence of training chirps for symbol alignment followed by a single opposite chirp for data alignment. Training chirps may be processed through a fast-Fourier transform (FFT) and the resulting values accumulated. The receiver may align, based on the received chirps of the preamble and the accumulated values exceeding the threshold, its symbol reception. Using this symbol alignment, the receiver may await a single opposite chirp after the sequence of training chirps. The single opposite chirp may indicate data alignment and comprise an encoded identifier. The receiver may reject the message and terminate further message processing based on the encoded identifier being a mismatch to a preconfigured identifier.