A communication system comprises at least a base station device and a terminal device. The terminal device transmits a demodulation reference signal associated with a physical channel, receives a configuration of comb of the demodulation reference signal, and transmits the demodulation reference signal mapped based on the configuration of comb. The base station device transmits a configuration of comb of a demodulation reference signal related to a physical channel.

A method controls a movement of a train to a stop at a stopping position between a first position and a second position. The method determines constraints of a velocity of the train with respect to a position of the train forming a feasible area for a state of the train during the movement, such that an upper curve bounding the feasible area has a zero velocity only at the second position, and a lower curve bounding the feasible region has a zero velocity only at the first position. Next, the method controls the movement of the train subject to the constraints.

A signal folding device receives an input signal, and performs frequency modulation on a plurality of first analog signals based on the input signal to obtain a plurality of modulated first analog signals, where a frequency difference between two adjacent first analog signals in the plurality of modulated first analog signals is the same. The signal folding device may filter the plurality of modulated first analog signals based on a specified bandwidth to obtain a second analog signal, and demodulate the second analog signal to obtain an output signal. The output signal is a folded signal of the input signal within a target amplitude, and the second analog signal is an analog signal within the bandwidth.

A tracking and rejection filter for use in a receiver of a radio includes a selectable filter configured to provide an output digital in-phase signal and an output digital quadrature signal based on a center frequency, a digital in-phase signal corresponding to an in-phase component of a received radio frequency signal, and a digital quadrature signal corresponding to a quadrature component of the received radio frequency signal. The tracking and rejection filter includes a select circuit configured to select the center frequency of the selectable filter according to whether an interfering signal is detected in a target frequency band of the received radio frequency signal. The center frequency is selected from a predetermined frequency and an estimated center frequency determined using an instantaneous frequency signal. The instantaneous frequency signal is based on the digital in-phase signal and the digital quadrature signal.

A tracking and rejection filter for use in a receiver of a radio includes a selectable filter configured to provide an output digital in-phase signal and an output digital quadrature signal based on a center frequency, a digital in-phase signal corresponding to an in-phase component of a received radio frequency signal, and a digital quadrature signal corresponding to a quadrature component of the received radio frequency signal. The tracking and rejection filter includes a select circuit configured to select the center frequency of the selectable filter according to whether an interfering signal is detected in a target frequency band of the received radio frequency signal. The center frequency is selected from a predetermined frequency and an estimated center frequency determined using an instantaneous frequency signal. The instantaneous frequency signal is based on the digital in-phase signal and the digital quadrature signal.

To provide a DC-DC converter capable of reducing noise and a wireless communication device including the same, the DC-DC converter according to an embodiment includes a pulse signal generation unit generating a pulse signal, a voltage conversion unit that has a switch portion provided between an input terminal and an output terminal and on/off controlled by the pulse signal, and outputs an output voltage obtained by stepping down an input voltage supplied to the input terminal, from the output terminal, and a control circuit that controls a value of a current flowing through the switch portion in an on-state based on a value of the input voltage.

To provide a DC-DC converter capable of reducing noise and a wireless communication device including the same, the DC-DC converter according to an embodiment includes a pulse signal generation unit generating a pulse signal, a voltage conversion unit that has a switch portion provided between an input terminal and an output terminal and on/off controlled by the pulse signal, and outputs an output voltage obtained by stepping down an input voltage supplied to the input terminal, from the output terminal, and a control circuit that controls a value of a current flowing through the switch portion in an on-state based on a value of the input voltage.

A correlating mixed signal spectrum analyzer receiver is provided that automatically correlates signals in a mixed-signal environment with a large number of waveforms having different characteristics corresponding to different protocols and modulation types, with the receiver utilizing either parallel correlators or sequential correlations to automatically accommodate the different waveforms such that in any given testing cycle, the spectrum analyzer runs through a comprehensive list of waveforms to detect the existence of corresponding signals. Frequency drift compensation and the utilization of multiple receivers for providing time difference of arrival calculations is described.

A transmitter for use in a communication system uses a orthogonal modulation method, and the transmitter includes: an orthogonal sequence prescriber that prescribes association between orthogonal signals and information words determined on the basis of sizes of differences between information words of a plurality of mutually different information words and a probability of occurrence of decision errors between orthogonal signals of a plurality of mutually orthogonal signals; and a symbol mapper that, upon input of any of the information words, generates modulation symbols based on the orthogonal signals associated with the input information word according to the associations prescribed by the orthogonal sequence prescriber.

A transmitter for use in a communication system uses a orthogonal modulation method, and the transmitter includes: an orthogonal sequence prescriber that prescribes association between orthogonal signals and information words determined on the basis of sizes of differences between information words of a plurality of mutually different information words and a probability of occurrence of decision errors between orthogonal signals of a plurality of mutually orthogonal signals; and a symbol mapper that, upon input of any of the information words, generates modulation symbols based on the orthogonal signals associated with the input information word according to the associations prescribed by the orthogonal sequence prescriber.