31results about How to "Reduce spurious signals" patented technology

The invention discloses a high-temperature superconducting duplex subsystem which is packaged in a refrigerator in vacuum; and the operating temperature is kept to be lower than the transition temperature of a superconducting material. The high-temperature superconducting duplex subsystem comprises two radio frequency (RF) ports, a large-power superconducting filter, a first circulator, a second circulator, a receiving channel and a microwave element. The system is applied in a wireless system and can realize the situation of simultaneously receiving and sending wireless signals.

The invention discloses a microwave photon mixing method and system based on local oscillator frequency doubling, and belongs to the fields of optical communication and microwave photonics. The microwave photon mixing system based on local oscillator frequency doubling is formed by utilizing a double-polarization double-parallel mach-zehnder modulator through combination with devices such as a laser, a front polarization controller, a microwave 90-degree coupler, a rear polarization controller, an optical fiber polarizer, an adjustable optical band-pass filter, an erbium-doped fiber amplifier,a photoelectric detector and the like. The system adopts second-order local oscillator sideband and first-order radio frequency sideband beat frequencies, and mixing processing based on local oscillator frequency doubling can be realized; on one hand, the frequency requirement of a mixing system on a local oscillator signal is reduced, and on the other hand, due to the fact that a single-sidebandmodulation mode is adopted, stray signals can be effectively reduced. In addition, the mixing method can realize switching of up conversion and down conversion by changing a direct current bias voltage, and can be used for time-sharing transmitting and receiving of radio frequency.

The invention relates to a 1.7micron fiber laser amplifier which structurally mainly comprises a signal source, an optical isolator, a pumped source, two wavelength division multiplexers, three thulium doped quartz fiber segments, two band pass filters separating the three thulium doped quartz fiber segments, a fiber bragg grating (FBG) and a fiber jumper wire head. The problems of signal gain saturation caused by ASE in the central wavelength position and severe signal light re-absorption in the 1.7micron short-wavelength operation process of the thulium doped fiber amplifier can be solved effectively, and output of 1.7micron-waveband amplification signals is stable and efficient.

The invention discloses a high-temperature superconducting transceiver subsystem which is packaged in a refrigerating machine in vacuum to keep operating temperature to be lower than transformation temperature of a superconducting material. The system comprises three radio frequency ports, a high-power superconducting filter, a circulator and a receiving channel. The system is applied to a wireless system for transmitting / receiving a wireless signal by a transmitter and a receiver respectively, thus achieving the purpose of receiving and transmitting the wireless signal simultaneously.