4 results about "Zero frequency" patented technology

The application provides a modulation method and system of an orthogonal frequency division multiplexing signal, and belongs to the technical field of wireless communication. The method comprises the following steps: mapping a frequency domain data signal and a pilot signal to be transmitted into a frequency domain resource grid matrix; performing a frequency domain shift operation on each row vector of the frequency domain resource grid matrix, shifting a zero frequency component to the center of the vector, and obtaining a shifted matrix; and performing an inverse fast Fourier transform on each row vector of the shifted matrix, and obtaining a time domain orthogonal frequency division multiplexing symbol matrix as a modulation result. The application constructs the entire frequency domain resource into a two-dimensional matrix, and all subsequent signal processing operations are based on the row vectors of the two-dimensional matrix as a basic unit, and are completed through a series of explicit matrix and vector operation steps. Thus, the IFFT call for the entire frame, which is a black box, is decomposed into individual steps for a single symbol, which are visible and controllable, and the problem of opaque process is solved.

The present application relates to a kind of based on comb spectrum implementation wideband signal transmitting device amplitude phase flatness analytical method, comprising the following steps acquisition measured link's time domain complex IQ sampling data;Perform fast Fourier transform;Zero frequency component is moved to spectrum center;Calculate the index of each target frequency in spectrum array;The amplitude and phase at each index are calculated;Calculate preliminary amplitude error and phase error;Get amplitude flatness distortion;Interlaced phase correction is carried out;Phase unwrapping is carried out;Get phase flatness distortion;Filter out abnormal value;Output amplitude flatness distortion and phase flatness distortion result.The wideband signal transmitting device amplitude phase flatness analytical method based on comb spectrum implementation of the present application, system, device, processor and its computer readable storage medium, around the flatness calibration demand of wideband wireless signal transmitting device, obtains the flatness information of transmitting device from comb spectrum, realizes the asynchronous acquisition and efficient analysis without synchronization.

The application relates to the radar technical field and discloses a continuous wave radar detection method, which comprises the following steps: generating an initial radio frequency carrier signal; applying a preset frequency offset to the initial radio frequency carrier signal to generate a transmission signal; radiating the transmission signal to a detection space through a transmission antenna; receiving a return signal formed by reflection of the transmission signal by a target in the detection space through a receiving antenna; and mixing the return signal with the initial radio frequency carrier signal to obtain a first intermediate frequency signal; wherein the preset frequency offset is configured so that, for a stationary target, the first intermediate frequency signal is a signal with a frequency equal to a preset non-zero frequency value; and the first intermediate frequency signal is processed to obtain information related to the state of the target. The spectrum of the effective signal is actively shifted to a frequency point away from a high-noise low-frequency area, and the detection sensitivity for stationary or micro-motion targets is enhanced. The application further discloses a continuous wave radar detection device, a radar and a storage medium.

This invention discloses an adaptive cancellation circuit for a frequency-modulated continuous wave radar, comprising the following components: a power divider, which splits the radar signal into two output signals, namely a first transmitted signal and a second signal LO; and a mixer, which receives the two output signals from the power divider, one of which serves as the local oscillator and the other as the receiver; the self-coupling signal delay at the RF input port of the mixer is the same as the delay of the second signal LO. This invention increases the LO trace delay, making the LO trace path delay equal to the antenna self-coupling path delay, thereby bringing the self-coupling intermediate frequency (IF) signal output close to zero frequency. This allows the self-coupling IF signal to be easily filtered out, significantly reducing the signal-to-noise ratio degradation caused by the impulse response.