Embodiments described herein include a receiver, a method, and a plurality of high-pass filters for demodulating a radio frequency (RF) signal. An example receiver includes a plurality of high-pass filters. The receiver includes a demodulator configured to demodulate an RF signal received at an input of the demodulator and configured to output a demodulated signal. The receiver also includes a plurality of high-pass filters connected to an output of the demodulator. The plurality of high-pass filters are configured to receive the demodulated signal and configured to high-pass filter the demodulated signal. The plurality of high-pass filters are configured to operate with a first set of filter responses during a first time period of the demodulated signal and configured to operate with a second set of filter responses during a second time period of the demodulated signal.

A switching mixer array is disclosed for the mixing of a digital LO signal with an analog input signal. Each switching mixer in the array is configured to assume either a first switching state or second switching state responsive to a respective bit of the digital LO signal.

A switching mixer array is disclosed for the mixing of a digital LO signal with an analog input signal. Each switching mixer in the array is configured to assume either a first switching state or second switching state responsive to a respective bit of the digital LO signal.

A Radio Frequency (RF) receiver may include a lower-order phase shift keying (PSK) demodulation circuit configured to generate at least one locking parameter when performing a lower-order PSK demodulation of an RF receive signal having an interfering PSK signal component. A higher-order PSK demodulation circuit has a higher order than the lower-order PSK demodulation circuit, and locks to the RF receive signal using the at least one locking parameter from the lower-order PSK demodulation circuit. The higher-order PSK demodulation circuit performs the higher-order PSK demodulation of the RF receive signal based upon locking to the RF receive signal to determine the interfering PSK signal component.

A digital frequency modulation receiver includes a phase capturer, an adder, a digital filter and a phase estimator. The phase estimator is used to generate a first phase value according to an input signal. The adder is coupled to the phase estimator for subtracting a second phase value from the first phase value to generate a phase difference. The digital filter is coupled to the adder for performing a filtering calculation with the phase difference so as to generate a frequency variation signal. The phase estimator is coupled to the digital filter and the adder so as to update the second phase value according to the frequency variation signal.

In a method and system for decoding a differential M-ary phase or quadrature amplitude modulated signal, the incoming signal is decoded according to a plurality of different decoding rules, wherein said plurality of decoding rules correspond to different values of a resulting frequency difference or mismatch between a signal frequency and a local oscillator reference frequency. The invention allows to increase a tolerance window for the maximal allowable frequency offset, and thus helps to speed up an initial locking process or to allow for equipment which has a lower tuning granularity.

A safety system comprised of safety devices each worn by a caretaker and up to three people requiring minding, that alerts using color coded LED lights and audible tones when a monitored person is in danger. The device alerts if the person is beyond a preset distance, is close to or is in a body of water, or signals they are in trouble, using phased-array radar coupled with image processing.

The phased-array radar allows the remote sensing of water in either daylight or night. The phased-array radar comprises multiple antenna elements including an independent antenna element phase shifter allowing beamsteering. The device scans an object using a preset beamsteering algorithm independent of movement. The multiple antenna elements and beamsteering improve image data accuracy which is then interpreted and correlated with a body of water characteristics. The phased-array radar is also used for caretaker-monitored person communications.

A voltage controlled oscillator includes a first inductor; a first variable capacitance unit including a first variable capacitance element having a variable capacitance and a second variable capacitance element having a variable capacitance; a first node configured for application of a first voltage to the first variable capacitance unit; a cross-coupled unit including a first transistor and a second transistor, an output of the first transistor connected to an input of the second transistor; a current source configured to flow a current through the first inductor, the first transistor, and the second transistor; a second variable capacitance unit including a third variable capacitance element having a variable capacitance, and a fourth variable capacitance element having a variable capacitance; and a second node different from the first node configured for application of a second voltage to the second variable capacitance unit.

Example communication systems and methods are described. In one implementation, a method receives a first chaotic sequence of a first temporal length, and a second chaotic sequence of a second temporal length. The method also receives a data symbol for communication to a destination. Based on the data symbol, the second chaotic sequence is temporally shifted and combined with the first chaotic sequence to generate a composite chaotic sequence. The first chaotic sequence functions as a reference chaotic sequence while the second chaotic sequence functions as a data-carrying auxiliary chaotic sequence.

Disclosed are a frequency offset estimation method and apparatus in an optical transmission network and a storage medium. The method comprises: acquiring a data symbol to be frequency offset estimated, and eliminating a noise phase, a phase generated by a light source and an information phase in the data symbol to be frequency offset estimated; and performing a correlation operation on a data symbol with a set interval in the data symbol after the elimination processing and using a correlation operation result to determine a frequency offset estimation value.