161 results about "Direct transformation" patented technology

In a frequency modulation radio receiver with direct conversion, a local oscillator signal is generated having a frequency within a preselected frequency range and the frequency is varied in response to a variable low frequency signal; the local oscillator signal is mixed with a received signal to provide a baseband signal. The variable low frequency signal is generated by a controlled oscillator in inverse relationship to a direct current component in said baseband signal. In a frequency modulation radio transceiver a broadcast function is provided by varying the low frequency signal with an information signal with the resulting local oscillator frequency being varied accordingly and amplified for broadcast. The transceiver is controlled to operate alternately in either a receive mode and a broadcast mode at substantially the same frequency. While in the receive mode the controlled oscillator causes the local oscillator signal to be drawn toward the carrier frequency of a received signal yielding preferred direct conversion of modulating information into the base band.

Most modern integrated circuit transceivers, especially wireless LAN, utilize a direct conversion radio architecture, which is highly advantageous from the perspectives of cost and flexibility, there exist several performance impairments, including gain and phase imbalances between the in-phase (I) and quadrature (Q) of a transmitter or receiver. Disclosed herein is a signal processing methodology and system for compensation of I / Q imbalance for a direct conversion packet-switched OFDM communications system. The imbalance, which accounts for transmitter I / Q imbalance, RX I / Q imbalance, phase / frequency error, and dispersive multipath fading. Both frequency dependent I / Q imbalance and frequency independent cases are considered, covering both wideband and narrowband modulation. The proposed estimation algorithms operate within the fully compliant framework of existing multi-user OFDM radio standards (WLAN, LTE, WimAX). These algorithms accurately estimate and correct transceiver I / Q imbalance on a packet-by-packet basis, all within the receiver's digital baseband.

The DCOC block is used in ZIF BB to form HPF function to cancel dc offset with a penalty of small silicon area and low power consumption. It is a LPF plus a voltage to current conversion (VIC) resistor, and can hook up with any BB opamp used in signal path, to form a feedback loop, with or without signal gain stages in the loop. The BB opamp is used as a summing point. The summing method is input current summing. The cutoff frequency of the HPF function is thus defined by the integrator, the VIC resistor, and the feedback resistor in the summing opamp. The presence of the VIC resistor can drastically reduce the integrator capacitor and resistor values and thus save silicon area or improve receiver performance.

A radio frequency receiver includes an amplifier and a detector that produces a bias control signal indicating the level of the signal environment in which the receiver is currently operating. A bias generator sets the bias level of the amplifier according to the bias control signal, where the bias level tends to increase as the signal level increases. Further, the receiver, includes a first circuit adapted to receive a radio frequency input signal, the circuit having an adjustable bias level, a bias control having more than one level of control for generating a bias control signal based upon a base-band signal for controlling the first circuit and generating an output signal; and an alternative bypass switch across the first circuit so as to send a DC signal corresponding to the total power generated by said feedback means.

The invention belongs to the technical field of preparing ethyl levulinate, in particular to a direct transformation process of ethyl levulinate by hydrolysis of cellulose materials. The process comprises the following steps: adding the cellulose materials into a reaction system comprising ethanol, liquid acid catalyst / solid acid catalyst, and cosolvent, hydrolyzing for 2 to 60 minutes at the temperature of 150 to 230 DEG C to obtain hydrolyzate containing the ethyl levulinate, and purifying the hydrolyzate to obtain the ethyl levulinate. In the invention, the cosolvent is added into the hydrolysis system of the cellulose materials, and the intermediate products such as hydromethyl furfural, the levulinic acid and the like generated during the hydrolysis of the cellulose materials can be extracted into an organic phase containing the cosolvent in the presence of the cosolvent, thereby preventing the further reduction of the intermediate products, facilitating the reduction of by-products and facilitating the yield increase of ethyl levulinate.

The invention relates to a honeycomb core end surface gridding sizing process method based on adhesive film thermal fracture. The honeycomb core end surface gridding sizing process method comprises the following steps of: tensioning the end surface of a honeycomb core by designing a special tool; instantly heating the upper surface of the adhesive film which is flat adhered to the end surface of the honeycomb core by adopting a linear type heating device and a heat air blowing device so that the upper surface of the adhesive film is heated to be softened and inwards recessed into a honeycomb core grid under the action of gravity; reversely exerting high-pressure heat air on the adhesive film along the axial direction of the honeycomb core grid so that the adhesive film is expanded, fractured, shrunk and uniformly collected on the end surface of the seamed edge of the honeycomb core grid, and thus the direct transformation of an adhesive from an adhesive film state to a honeycomb gridding state is realized. The honeycomb core end surface gridding sizing process disclosed by the invention realizes the large-area, one-time, uniform and gridding sizing of the end surface of the honeycomb core by carrying out synchronous and horizontal heating / blowing scanning on the honeycomb core / adhesive film and sufficiently utilizing the advantage of uniformity of the surface density of the structural adhesive film and meets the requirements for small chemical state change and uniform physical distribution state of the large-area honeycomb core gridding sizing on the adhesive.

The invention belongs to the field of rare earth wet metallurgy and industrial chemistry, and relates to a clean production technology for roasting rare earth concentration to leach rare earth by the sulphate method. Aiming at the prior roasting production technology by the sulphate method taking Baotou rare earth concentration as raw materials, the technological process of the clean production technology realizes direct transformation production from sulphate to carbonate by the transformation technology of double decomposition reaction in chemical process and according to the principle of mutual transformation between solid substances with different solubility products. Non-rare-earth compounds (such as ammonium sulphate and ammonium carbonate) and the like are fully recovered with low cost; simultaneously, water can be fully recycled and used; the intermediate impurity removing technology is adopted to recover non-rare-earth substances such as Ca from rare earth ore. Therefore, the purpose of full-recycling and clean production in rare earth leaching process by the sulphate roasting method is realized. The technology has the advantages that the production process of rare earth ore sulphate method fully recovers rare earth elements and valuable elements from mineral products with lower cost, and clean production without sewage emission is realized.

A direct conversion receiver with an integrated self alignment tuner. The system includes a tank circuit, an analog to digital converter, a digital down converter, a digital up converter, a local oscillator, and a digital to analog converter. The tank circuit receives a radio frequency signal from an antenna input. The analog to digital converter is connected to the tank circuit to digitize the tank output signal and generate a corresponding digital signal. The digital down converter is in communication with the analog to digital converter and generates an intermediate frequency signal based on the digital signal and the output of the local oscillator. The digital up converter is in communication with the digital to analog converter to generate a radio frequency test signal, where the digital to analog converter provides the radio frequency test signal to the antenna input.

The invention discloses an electroencephalogram monitoring device with an epileptic seizure predicting function and a method. The electroencephalogram monitoring device and method can be applied to ascalp electroencephalograph machine or an embedded cortex electroencephalogram monitoring system. The method of the device comprises the following steps of 1, acquiring an electroencephalogram signalof a patient through an electroencephalogram acquisition device; 2, transmitting the electroencephalogram signal to an epileptic predicting alarming device; 3, judging the state of the patient throughan epilepticprediction algorithm module in the epileptic predicting alarming device, and once the epileptic measurement module judges that the patient is in the early stage of anepileptic seizure, sound-lightalarm can be triggered, and the patient and his / her dependents are prompted to take prevention measures. The epilepticprediction algorithm moduleuses a directed transformation function as a basis and characteristics of a connection matrix among electroencephalogram signals as parameters for predicting the epilepticseizure of the patient, the epileptic seizure can be predicted several dozens of minutes in advance, and the electroencephalogram monitoring device and method have high clinical and practical significance.