2results about "Pulse demodulator" patented technology

Circuit arrangement (100, 200, 300) for converting a digital signal into an analog signal, with: a first digitally controllable generator (V1) to provide a first digital signal; a second digitally controllable generator (D1, V2) to provide a second digital signal; wherein a circuit node (K1, K2) of the circuit arrangement (100, 200, 300) is electrically coupled to an output terminal of the first digitally controllable generator by means of a first coupling impedance (R1); and wherein the circuit node (K1, K2) is coupled to an output terminal of the second digitally controllable generator (D1, V2) by means of a second coupling impedance (R2); wherein the circuit arrangement comprises a plurality of digitally controllable generators (V52, V53, V54, V55) which are each electrically coupled to the circuit node (K1, K2, K3) by means of a respective coupling impedance (R52, R53, R54, R55), wherein the multiple digitally controllable generators (V52, V53, V54, V55) each provide a pulse-width modulated signal, and wherein the respective digitally controllable generators (V52, V53, V54, V55) are configured such that the respective pulse-width modulated signals have a clock shift relative to each other of 360 degrees divided by a number of the multitude of digitally controllable generators; and a filter circuit (C1, C32) coupled to the circuit node (K1, K2) to provide the analog signal; wherein the first digitally controllable generator (V1) and the second digitally controllable generator (D1, V2) are coupled such that there is a fixed phase relationship between the first digital signal and the second digital signal in order to achieve the lowest possible residual ripple of the analog signal with the circuit arrangement (100, 200, 300).

The application belongs to the technical field of test and measurement of optical fiber sensing and signal processing, and discloses a distributed acoustic sensing system based on pulse compression and a signal demodulation method. In the method, original echo signals are collected and segmented according to a pulse repetition period to form sample traces; a multi-band sub-match filter bank is constructed, fast Fourier transform, frequency domain complex multiplication and inverse fast Fourier transform are respectively performed on the sample traces in each frequency band, and a pulse compression complex sequence is obtained; group time delay compensation is performed on the reference band, so that each frequency band is aligned under the reference of uniform sample point sequence numbers; a phase reference is established by taking the complex conjugate of the pulse compression complex sequence of the first sample trace point by point, and phase correction is completed by performing point-by-point complex multiplication on the subsequent sample traces; complex vector superposition is performed on the phase correction results of each frequency band, a demodulation output is obtained, and the phase reference is updated according to a phase refresh period.