7 results about "Frequency profile" patented technology

Digital radio transmitters and data transmission methods are provided. Chirp-based spread spectrum digital radio transmitters are configured to suppress or attenuate discontinuities in the chirp frequency profile by an interpolation or smoothing procedure. The interpolation significantly reduces out-of-band emissions and does not affect demodulation and decoding. In the case of LoRa communications, the transmitter of the invention has low constellation error and can communicate with conventional unmodified receivers. The procedure does not introduce unwanted phase shifts and can be used to control the phase of the signal, also inserting arbitrary phase shifts on consecutive segments of the chirp.

The application discloses a kind of bionic concealed underwater acoustic communication detection integrated method.Existing method does not consider the concealment of communication and detection jointly.The method of the present application first extracts click sound signal and whistle signal, and carries out power and correlation screening;Then the original click sound signal is waveform encoded and pulse position modulated, and the original whistle signal is time-frequency shape encoded and waveform parameter modulated.Using the good detection performance of bionic modulated signal, generate bionic communication detection integrated signal.In echo signal receiving end, different echo signal processing method is used.In communication receiving end, combined demodulation method is used.The bionic whistle signal generated by the present application has high similarity with the original signal in time domain, and the time-frequency profile is continuous.The present application can improve the communication rate by sampling combined modulation, has good concealment, not only can realize the accurate estimation of target distance, speed and azimuth, but also has good communication performance.

A method for equalizing an audio frequency signal broadcast in a broadcasting environment. Such a method includes: estimating a frequency profile of a noise signal representing a background noise present in the broadcasting environment, based on, on the one hand, a signal captured by at least one microphone implemented in the broadcasting environment and, on the other hand, the audio frequency signal; determining a desired frequency profile for the broadcast audio frequency signal; determining an acoustic frequency mask representing, for each frequency component, a difference between the frequency profile of the noise signal and the desired frequency profile; and equalizing the audio frequency signal via a weighting of a spectrum of the audio frequency signal by applying a frequency weighting mask that is a function of the acoustic frequency mask, delivering the equalized audio frequency signal.

A chirp-based spread spectrum digital radio transmitter configured to suppress or attenuate discontinuities in the chirp frequency profile with an interpolation or smoothing procedure. The interpolation reduces significantly out-of-band emissions and does not affect the demodulation and decoding. In the case of a LoRa communication, the inventive transmitter has low constellation error and can communicate with legacy unmodified receivers. The process does not introduce unwanted phase shifts and can be used to control the signal's phase, also on continuous segments of the chirp to insert an arbitrary phase shift.

The application discloses a two-dimensional transient extraction complex superimposed dense channel reservoir characterization method, which comprises the following steps: S1, inputting a two-dimensional seismic profile d(t, x), wherein t is time and x is trace number; S2, performing short-time Fourier transform S(t, omega, x, k) on the seismic profile by using a two-dimensional Gaussian window function, wherein omega is frequency and k is wave number; S3, obtaining group delay t0(t, omega, x, k) in time and group delay x0(t, omega, x, k) in space by respectively taking partial derivatives of S(t, omega, x, k) with respect to frequency and wave number; S4, obtaining a two-dimensional extraction operator TDTEO(t, omega, x, k); S5, further obtaining a two-dimensional transient extraction transform TDTET(t, omega, x, k) of seismic data; S6, determining the wave number by energy maximization, obtaining a time-frequency-space domain three-dimensional data body TDTET(t, omega, x, k(t, x, omega)), and obtaining corresponding single-frequency profiles according to required frequencies to perform morphology characterization on the single-frequency profiles. The application can improve energy focusing, effectively eliminate interference phenomenon and be better applied to complex superimposed dense channel characterization.

A fluid pump for pumping fluid between a fluid inlet and a fluid outlet has a chamber with an inlet and an outlet. At least one flow restriction element is provided at a flow line portion and is configured to resonate along a continuum of states between a first end state and a second end state, thereby exerting an influence on the fluid flow profile through the inlet or the outlet. At resonance, the element transitions through a range of states, each of which allows a different flow. The transition is through a range of states with different allowed flows. A driver is configured to modulate conditions in the chamber or on the at least one flow restriction element with a characteristic frequency profile, thereby causing the at least one flow restriction element to resonate between the first state and the second state at about the characteristic frequency profile.