37 results about "Double side band" patented technology

The invention belongs to a method for generating a single high-frequency side band millimeter wave signal by using a smaller-bandwidth intensity modulator and a lower-frequency radio-frequency signal The invention belongs to a method for generating a single high-frequency side band millimeter wave signal by using a smaller-bandwidth intensity modulator and a lower-frequency radio-frequency signalin the technical field of Radio-over-Fiber (abbreviated as ROF). The system makes full use of the reliability and low cost characteristics of double-side-band modulation and the excellent signal perfoin the technical field of Radio-over-Fiber (abbreviated as ROF). The system makes full use of the reliability and low cost characteristics of double-side-band modulation and the excellent signal performance and fiber dispersion of single-side-band modulation. At a central station, multiple double-frequency technology is adopted to generate high-frequency millimeter microwaves, so the requirementsrmance and fiber dispersion of single-side-band modulation. At a central station, multiple double-frequency technology is adopted to generate high-frequency millimeter microwaves, so the requirementsof the central station on element bandwidth are reduced and the configuration of the central station is simple and easy to realize, and the cost of the central station is reduced. A base station usesof the central station on element bandwidth are reduced and the configuration of the central station is simple and easy to realize, and the cost of the central station is reduced. A base station usesa filter to acquire a single-side-band signal having a bandwidth which is two times of that of the conventional single-side-band. Therefore, a higher direct current component at a central carrier wavea filter to acquire a single-side-band signal having a bandwidth which is two times of that of the conventional single-side-band. Therefore, a higher direct current component at a central carrier waveposition generated when the single-side-band modulation is used directly is avoided and the influence of the fiber dispersion on the signal is reduced. In addition, the method can filter the central position generated when the single-side-band modulation is used directly is avoided and the influence of the fiber dispersion on the signal is reduced. In addition, the method can filter the centralcarrier waves of the ROF millimeter waves from a down link and be used for reusing the wavelength of an up link, and simplifies the base station.carrier waves of the ROF millimeter waves from a down link and be used for reusing the wavelength of an up link, and simplifies the base station.

The invention discloses a measuring method and system for frequency response of an electro-optical modulator. A light beam splitter divides optical carrier signals into an upper path and a lower path; in the upper path, a Mach-Zehnder modulator modulates microwave signals output by a microwave source 1 to optical carrier waves, and double-side-band signals which inhibit the carrier waves are generated, and serve as pumping signals after being amplified; and in the lower path, the electro-optical modulator to be measured modulates microwave signals output by a microwave source 2 to optical carrier waves, and double-side-band signals are generated. The frequencies of the microwave source 1 and the microwave source 2 are adjusted, so that the double-side-band signals output by the electro-optical modulator to be measured form single-side-band signals in a Brillouin medium. A photoelectric detector converts the single-side-band signals into electric signals, an amplitude-phase receiver extracts amplitude and phase information from the electric signals, and combined response of the electro-optical modulator to be measured and the photoelectric detector are obtained; and the frequency response of the electro-optical modulator to be measured is obtained by removing the frequency response of the photoelectric detector.

The invention provides a double side band frequency diversity array radar system and an object positioning method thereof and belongs to the technical field of radar signal processing. The double side band frequency diversity array radar system consists of N array elements that are linearly and uniformly arranged at an interval, N is a positive integer, and each array element comprises an emitting part and a receiving part. The emitting part comprises a modulation signal generator, a double side band modulator and an emitting antenna, wherein an output end of the modulation signal generator is connected with an input end of the double side band modulator, and an output end of the double side band modulator is connected with the emitting antenna. The receiving part comprises a receiving antenna, a filter group and a positioning calculation unit, wherein the filter group consists of two narrow band filters that are different in frequency, the receiving antenna is connected with input ends of the two narrow band filters, and output ends of the two narrow band filters are connected with an input end of the positioning calculation unit.