16 results about "Noise figure" patented technology

This invention belongs to the field of nasal alar pulse wave signal processing technology, and provides a method, apparatus, medium, and wearable device for nasal alar pulse wave signal processing. The method includes: extracting the respiratory cycle based on the respiratory signal; determining the length of the mean sliding filter window to filter out the DC component of the original nasal alar pulse wave signal, obtaining a filtered nasal alar pulse wave signal; extracting the amplitude of the AC component of the filtered nasal alar pulse wave signal; adjusting the current of the light source element corresponding to the pulse wave signal sensing element to make the amplitude of the AC component of the filtered nasal alar pulse wave signal greater than or equal to a preset amplitude threshold; further filtering the nasal alar pulse wave signal using an adaptive weighted moving average filtering algorithm; and determining whether a nasal alar pulse wave signal meeting preset quality requirements is obtained based on a comparison between the noise figure of the further filtered nasal alar pulse wave signal and a preset noise figure threshold.

FIELD: microwave electronic devices.SUBSTANCE: in a low-noise microwave field-effect transistor on a semiconductor heterostructure, at least three quantum barrier layers of i-AlAs are additionally made, each with a thickness of 2-6 atomic monolayers, wherein each of said quantum barrier layers is located between the actual channel layer of InyGa1-yAs or a group of layers of the latter and the gate, wherein at least one quantum barrier layer is located between the doped layer and, or δ n-layer and the actual channel layer of InyGa1-yAs or a group of layers of the latter and at least one quantum barrier layer is located between the doped layer and, orδ n-layer and a gate, wherein the quantum barrier layers are separated from each other by at least one layer of narrow-band material AlxGa1-xAs, with a molar fraction of the chemical element Al x less than 0.4, with a thickness equal to or greater than 2 atomic monolayers, or a layer of GaAs, with a thickness equal to or greater than 2 atomic monolayers, between the actual channel layer InyGa1-yAs or a group of layers of the latter and the buffer layer, layers of GaAs, transition layers, quantum barrier layers i-AlAs, barrier layers, and layers doped with an acceptor impurity are made, on the last layer of the group of barrier layers, quantum barrier layers i-AlAs, barrier, transition and contact layers are made in a given sequence.EFFECT: increase in the gain factor and a reduction in the noise figure.1 cl, 1 dwg, 1 tbl

This invention discloses a packet loss detection method for unmanned surface vessel (USV) formations based on adaptive fuzzy membership filtering. The method includes: establishing state equations describing the motion of both the leader and follower USVs; linearizing these nonlinear equations to simplify the complex curvilinear motion relationships into linear mathematical expressions, thus obtaining simplified state equations for the entire formation system; introducing an adjustable measurement noise figure based on the simplified formation model, dynamically adjusting the filtering intensity according to the current measurement noise level, thereby more accurately estimating the real-time state of the USVs; and simultaneously detecting packet loss during state updates, combining preset communication quality indicators and real-time calculated noise levels to determine the reliability of received data. This invention achieves good detection results for packet loss in noisy channels and can be widely applied in the field of data detection.

This application provides an erbium-doped optical fiber, an optical amplifier, and a communication device, relating to the field of optical communication technology. The erbium-doped optical fiber is a radiation-resistant erbium-doped fiber, exhibiting good gain and a low noise figure. The erbium-doped optical fiber includes a core and a cladding, with the cladding enclosing the core. It also includes a radiation-resistant layer disposed between the core and the cladding, comprising germanium, fluorine, and silicon dioxide. The absolute value of the difference between the refractive index of the radiation-resistant layer and the refractive index of the core is less than the absolute value of the difference between the refractive index of the radiation-resistant layer and the refractive index of the cladding.

This invention discloses a current-multiplexed millimeter-wave variable gain amplifier based on interstage mutual coupling inductor matching. It employs a two-stage cascaded structure, including an input matching network, a low-noise module, an interstage matching network, a variable gain module, and an output matching network. The input terminal of the low-noise module is connected to the output terminal of the input matching network. The low-noise module and the variable gain module are connected through the interstage matching network. The output terminal of the variable gain module is connected to the input terminal of the output matching network. This invention overcomes the problems of high noise figure, high power consumption, and high phase error in existing variable gain amplifiers.

The application discloses an ultra-wideband GaAs amplitude-phase control transceiver front-end chip, which is applied to the field of phased array radars, and aims at the fact that high-low pass type phase shifters adopted in existing transceiver front-end chips are only applicable to low-frequency phase shift units, and are limited by the problem of filter order; the application proposes a novel phase shift structure based on a magnetic coupling all-pass network and an active complementary dual-mode amplification circuit, the structure can realize a great expansion of available frequency on the premise of ensuring phase shift precision, and a 180-degree phase shift network based on an active structure can effectively provide transmission gain, reduce the number of used link amplifiers, further reduce the noise coefficient of a receiving link and assist in improving the power characteristics of a transmitting link. The application of the technology helps to realize good phase shift precision, input and output return loss and lower phase shift error of the chip in an ultra-wideband range of 2-18GHz.

This invention discloses a transformer-based noise cancellation receiver front-end circuit, including a low-noise transconductance amplifier circuit, a passive mixer, and a transimpedance amplifier. The low-noise transconductance amplifier circuit uses a cascode cascade structure, which not only achieves noise cancellation but also enables two differential current outputs. Transformer coupling at the input increases the equivalent transconductance, reducing power consumption. The baseband transimpedance amplifier uses a two-stage structure with feedforward compensation to achieve a large bandwidth. Furthermore, this receiver achieves a baseband bandwidth of 220MHz in the RF frequency range of 5.5-6.5GHz, with a noise figure below 2.45dB.

Split low noise amplifier (LNA) architectures providing an improved tradeoff between the noise figure (NF) and the output-to-output isolation are disclosed. The described LNAs include cascode transistors in two amplification paths and an inductive element including a pair of inductors and a common inductor. The inductance values of the inductors and the common inductor can be selected to obtain an improved tradeoff between the NF and isolation while meeting the output matching conditions.

The present application relates to the technical field of testing, in particular to a noise figure test automatic calibration, compensation and correction method and system. The method comprises the following steps: obtaining the loss L of a microwave switch matrix; obtaining the equivalent noise temperature obtained by a test of a measured object and the test gain of the measured object; obtaining the real equivalent noise temperature of the measured object based on the loss L of the microwave switch matrix, the equivalent noise temperature obtained by the test of the measured object, the test gain of the measured object, a standard noise temperature; and converting the real equivalent noise temperature of the measured object into the real noise figure of the measured object. The present application can realize automatic calibration and compensation of noise figure test based on the Y-factor method, and support full-automatic testing of an automatic test system.

The application discloses an ultra-wideband variable gain low noise coefficient amplifier with constant high linearity, comprising a first-stage inverting amplifier, a second-stage common-source amplifier, a third-stage inverting amplifier and a fourth-stage inverting amplifier connected in sequence, the first-stage inverting amplifier adopts a Gm-boost resistance feedback structure to improve gain and improve noise coefficient, the second-stage common-source amplifier and the third-stage inverting amplifier adopt a parallel MOS tube array structure to realize circuit gain switching, large bandwidth, constant high linearity and working capacity, and the fourth-stage inverting amplifier is connected with a signal output end. The application has the characteristics of ultra-large bandwidth, variable gain, low noise coefficient and constant high linearity in a working frequency band.

The application discloses a kind of automatic high signal-to-noise ratio configuration system and method of wavelength division multiplexing, the system includes n sites, the first site in optical transmission direction is equipped with power amplifier, each site is equipped with optical amplifier and variable optical attenuator in the rest, NF configuration parameter memory is further equipped in each site, the NF configuration parameter memory in the first site is used to store the gain and noise figure of power amplifier in this site, and the relationship data of input power and noise figure of this site, the NF configuration parameter memory in the rest each site is used to store the gain and noise figure of optical amplifier in corresponding site, the gain and noise figure of variable optical attenuator, and the relationship data of input power and noise figure of this site.The application can automatically configure optimal parameter, so that the overall noise figure NF of system is minimum, so as to reach high signal-to-noise ratio, so that the system based on WDM works in the best state, reduces error rate.

The application provides an X-band weather radar double-channel multifunctional receiving assembly, and relates to the technical field of communication, which comprises: parallel receiving of horizontal and vertical polarization echo signals, twice frequency down-conversion by using first and second local oscillator signals, two digital intermediate frequency signals obtained through a digital intermediate frequency processing module; meanwhile, an up-conversion excitation signal is input into a transmitting chain; a function calibration module calibrates the noise coefficient of a receiving channel, calibrates the delay of a transmission path, and feeds a coupled sample of a transmitting signal into a receiving channel for power monitoring to determine a link gain compensation coefficient; the local oscillator signal and the digital intermediate frequency signal are led out to an external interface for monitoring the frequency source performance and amplitude and phase consistency; two signals are calibrated according to the compensation coefficient, differential reflectivity and differential phase are extracted, precipitation particle phase state structure is analyzed, strong convective weather core areas are determined and circled, and the automation level and early warning timeliness of the X-band weather radar in short-term early warning business are significantly improved.

The application discloses an erbium-doped optical fiber. The erbium-doped optical fiber can be applied to the fields of amplifiers, optical communication and rare earth-doped optical fiber preparation. The core of the erbium-doped optical fiber comprises a first layer and a second layer from inside to outside. The first layer comprises the center of the core. The second layer is annular, and the outer ring of the annular ring is the outer ring of the core. The average erbium ion doping concentration of the first layer is higher than that of the second layer. In the application, by reducing the erbium ion doping concentration of the second layer, the ASE can be reduced, the noise figure of the erbium-doped optical fiber is reduced, and the communication quality is improved.

The application provides a large antenna array and a phase consistency design method thereof, and the design method comprises the following steps: recording cables between a signal generator and a power amplifier array as first cables, and dividing the first cables into i groups; recording cables between the power amplifier array and an antenna array as second cables, the total number of the second cables is N times of the total number of the first cables, and the second cables are divided into i groups corresponding to the first cables; and the first cables and the second cables between each group of cables adopt an asymmetric cable layout to ensure that the phase consistency of the large antenna array meets the requirements. The application can improve the array surface power efficiency, reduce the system noise coefficient, and reduce the difficulty of array cable arrangement.