68 results about "Digital up converter" patented technology

A digital transmitter (20) that may be advantageously used in a high-frequency transceiver, such as a wireless telephone handset, is disclosed. The transmitter (20) includes digital upconverter functions (36L, 36Q) that operate in combination with a digital band-pass sigma-delta modulator (40) to generate modulated digital signals at a sample frequency that is a multiple of the transmit frequency. The digital band-pass sigma-delta modulator (40) applies a noise transfer function in a feedback filter (72) in which the center of the pass band corresponds to the transmit frequency, and in which notches in the characteristic can be symmetrically or asymmetrically selected to correspond to specific frequencies, such as the receive band frequency, in which transmit noise is to be minimized. A combined FIR digital filter (42) and MOS power switch array (44) is also disclosed, in which a cascode arrangement of drain-extended MOS power transistors (78) and switching transistors (82) provide the output RF signal, with a coarse gain control (80) applied.

The invention discloses a mobile communication direct amplifying station with digital intermediate frequency. Wherein, transforming the down signal into analog intermediate frequency signal with RF module to send to ADC/DAC group and transform into digital intermediate frequency signal by A/D; extracting and filtering with digital down converter, and secondary transforming into baseband signal to send to baseband treatment unit for packaging into serial data as given frame format; transferring with optical fiber to high-speed digital optical fiber transceiver on cover end to de-frame with baseband treatment unit and send into ADC/DAC group; filtering and interpolating with digital up converter, transforming into analog intermediate frequency signal by D/A converter; finally, taking frequency conversion with RF module into RF signal and sending to opposite over area. The remote machine sends received up signal of mobile terminal with said inverse process to receiving end of base station. This invention avoids intrinsic leakage and dc offset in prior art.

A cable modem is provided. The cable modem may include: a plurality of modulators to generate a plurality of pieces of digital data corresponding to a plurality of independent channels; a plurality of digital upconverters to up-convert a frequency of each of the plurality of pieces of digital data into a predetermined frequency; and a Radio Frequency (RF) processor to channel-bond outputs of the plurality of digital upconverters into at least one channel, and generate an analog output signal, the outputs having the predetermined frequency.

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 a multimode radio frequency signal generator, comprising a personal computer as well as a baseband I, a Q signal generator, a multi-carrier digital up-converter subsystem, a D/A converter, a clock subsystem and a microchip control subsystem that are respectively connected with the multimode radio frequency signal generator; wherein, the baseband I and the Q signal generator are connected with the multi-carrier digital up-converter subsystem, the D/A converter and a radio frequency subsystem in sequence; the clock subsystem is simultaneously connected with the baseband I, the Q signal generator, the multi-carrier digital up-converter subsystem, the D/A converter, the radio frequency subsystem and the microchip control subsystem; the microchip control subsystem is connected with the baseband I, the Q signal generator, the multi-carrier digital up-converter subsystem, the D/A converter and the radio frequency subsystem at the same time; the radio frequency subsystem is provided with a multimode multi-carrier radio frequency signal output end. The multimode radio frequency signal generator has the advantages of excellent performance, good feasibility, strong system flexibility and expandability as well as easy realization of system miniaturization and low power consumption.

A digital up-converter (DUC) circuit for performing digital channel filtering of an incoming baseband digital signal. The proposed circuit reduces the complexity of the channel module filter of the DUC. This is achieved by taking advantage of the structure of the underlying symbol waveforms carried by the incoming baseband digital signal which have one or more known discontinuities comprising random amplitude and/or phase. Namely, the channel filter module is activated only for the digital samples located around the known discontinuities and is deactivated for the remaining digital samples. Further, the switching of the channel filter module from one state to another can be performed according to a smooth function so that further discontinuities are not introduced in the incoming baseband digital signal. A method and a computer program are also disclosed.

The invention relates to the field of liquid level measurement device, specifically a method of liquid level measurement with radar and radar liquid level instrument with this method. To solve the current problems of low accuracy of measurement result and high cost, the invention employs the technical project: a method of liquid level measurement with radar, the liquid level to be measured can be obtained based on the formula L=H-c1(Deltphi11/4 piDeltf1); a radar liquid level instrument with this method includes radio-frequency unit, transmitting element, receiving element and processing unit, radio-frequency unit includes reference clock source and clock source, reference clock source is connected with the clock source in radio-frequency unit; said transmitting element comprises digit up converter, D/A converter and low-pass filter, said receiving element includes low-pass filter and digit down converter and D/A converter.

The invention provides a digital down converter and a digital upconverter. Intermediate-frequency signals are mixed by a first-level mixing module in the digital down converter; two paths of I/Q mixing signals are output in a two-carrier time division multiplexing mode; a first-level multi-rate conversion module and a second-level multi-rate conversion module synchronize clock frequency before extraction; and the received signals are subjected to multiple extraction and filtration in a multi-carrier time division multiplexing mode according to the synchronized clock frequency. The digital upconverter synchronizes the clock frequency before frequency interpolation; a third-level multi-rate conversion module, a fourth-level multi-rate conversion module, a second-level mixing module and a fifth-level multi-rate conversion module perform frequency interpolation and filtration on the received signals in the multi-carrier time division multiplexing mode according to the synchronized clock frequency and the received signal data rate. The converter reduces the complexity of a control signal and saves logical resources.

The invention provides a repeater station carrier fluctuation calibration method which comprises the steps of generating a carrier signal of which the amplitude is a constant and transmitting the carrier signal to a digital up converter module, counting the carrier output power of an output signal of the digital up converter module, calculating the power difference between the carrier output power and a corresponding carrier feedback power and calibrating a gain compensation parameter of a corresponding carrier in the digital up converter module according to the power difference. The invention further provides a repeater station carrier fluctuation calibration device. By the adoption of the technology of the invention, a direct-current signal source can be generated inside a repeater station, fluctuation calibration can be carried out without configuring signal source equipment, the operation is flexible, the efficiency is high, the fluctuation calibration process is greatly simplified, the direct-current signal waveform is smooth, and the direct-current signal source can be used as a signal source for fluctuation calibration to obtain a higher calibration accuracy.

The invention discloses a CDMA communication anti-interference system based on frequency domain filtering. The CDMA communication anti-interference system comprises a signal preprocessing portion, a frequency domain processing portion and a post-processing portion, wherein the signal preprocessing portion comprises an A/D collector, a digital down-converter, a low-pass filter and an extractor which are connected in sequence; the frequency domain processing portion comprises two routes, one route comprises a windowing device, an FFT device, a threshold value generating and spectral line processing device, an IFFT device and 50% delay device which are connected in sequence, the other route comprises a 50% delay device, a windowing device, an FFT device, a threshold value generating and spectral line processing device and an IFFT device which are connected in sequence, and finally, the two routes are connected with an adding device simultaneously; the post-processing portion comprises an interpolation device, a filter, a digital up-converter and a D/A converter which are connected in sequence. The invention further discloses a CDMA communication anti-interference method based on frequency domain filtering. By means of the system and the method, the anti-interference ability of the system is effectively enhanced.

The invention provides a self-adaptive interference cancellation control device which is used in wireless same-frequency relay equipment. The self-adaptive interference cancellation control device comprises an adder/subtractor, an automatic gain control module, an adaptive filter, an interference canceller and a delayer. One input end of the adder/subtracter is connected with a digital down converter in the wireless same-frequency relay equipment; the output end of the adaptive filter is connected with the other input end of the adder/subtracter through the interference canceller; the output end of the adder/subtractor is connected with the input end of the automatic gain control module, one output end of the automatic gain control module is connected with the input end of the self-adaptive filter through the delayer, and the other output end of the automatic gain control module is connected with a digital up-converter in the wireless same-frequency relay device. The invention furtherprovides a self-adaptive interference cancellation wireless same-frequency relay system and a self-adaptive interference cancellation control method, and the self-excitation problem of the wireless same-frequency relay equipment can be effectively solved.

The invention discloses a method for testing a satellite mobile communication terminal digital up-converter. A PC (Personal Computer) machine is connected with an FPGA (Field Programmable Gate Array) in the digital up-converter, the FPGA is controlled to generate I/Q (In-phase/Quadrature) data of an analog baseband signal and the I/Q data is input into an AD9957 chip to be converted into an analog signal to output; the analog signal output by the AD9957 chip enters an SAW (Surface Acoustic Wave) filter by a first RF (Radio Frequency) transformer and a first spectrum analyzer is connected between the first RF transformer and the SAW filter; and an output signal of the SAW filter enters an AD8370 chip by a second RF transformer, an output signal of the AD8370 chip is output by a third RF transformer and a second spectrum analyzer is connected to the output end of a third RF amplifier. By utilizing testing equipment such as the PC machine, the spectrum analyzers and the like, various functional indexes of the digital up-converter can be well tested and whether the indexes meet the design requirements is judged, so that the performance of the satellite mobile communication terminal digital up-converter is ensured.

The invention relates to an automatic detection and application method of optical port transmission rate, which can realize two types of selective transmission of optical rate and comprises the steps of: 1, in a downlink, transmitting 1.25Gbps data according to 2.5Gbps, and converting the 1.25Gbps data into two paths of data with parallel high-low levels through a DDR (Double Data Rate) module; judging optical port transmission rates and then generating corresponding indicating signals; and respectively selecting all carriers as required from a plurality of antenna carriers for the two types of optical port transmission rates, and transmitting to a DUC (Digital Up Converter) module for transmitting out of a base band; and (2) in an uplink, inserting a plurality of carriers into corresponding antenna carriers according to the indicating signals; and then dividing the 1.25Gbps data into two same high-low level data, transmitting the data out of the base band through the DDR module to combine the data into a string and converting a processing chip. The invention is beneficial to reducing research and development cost and maintenance cost in a large scale, and adaptively detects the optical transmission rate through software without excessive manual intervention.

A transmitter includes a first digital up-converter for converting data to an intermediate frequency (IF) signal, a pulse width modulator (PWM) for encoding the IF signal to an IF pulse train, a second digital up-converter for converting the IF pulse train to a radio frequency (RF) pulse train, a power amplifier for amplifying the RF pulse train; and a filter for reconstructing a RF analog signal from the amplified RF pulse train.

The method includes steps: obtaining coefficient of temperature compensation from ambient temperature and empirical value; using the coefficient to control amplitude of baseband signal, and further to control emission power of system. The equipment includes module of temperature collection and processor, module for processing code element in baseband, digital up converter, and D/A converter. The invention implements power control at base band, providing high precision for temperature compensation of power. Moreover, the invention removes complicated compensation circuit in radio frequency so as to simplify system and reduce cost. Features are: easy controlled flexible adjustment of step size, reduced interference between systems, raised system capacity etc.

The invention discloses a PA (power amplifier) overpower protecting method and a PA overpower protecting device, which is used for realizing the more complete overpower protection of a PA. The method comprises the following steps that the existing statistical energy protection mechanism is adopted; by aiming at in-phase component and orthogonal component data of phase and amplitude signals of each antennas subjected to DUC (digital up converter), CFR (crest ractor reduction) and DPD (digital pre distortion) processing, the sum of the energy value of the orthogonal component data and the energy value of the in-phase component of phase and amplitude signals in each second time duration is respectively calculated, and the second sum value is obtained; and the second sum value is compared with the preset second power protection threshold value, and when the second sum value of any one antenna is greater than the second power protection threshold value, the in-phase component and orthogonal component data of the phase and amplitude signals in each second time duration is sent to the PA after zero clearing, wherein the second time duration is smaller than 1 chip, so the more complete overpower protection of the PA is realized.

The invention provides a baseband signal processing platform based on software radio. The baseband signal processing platform includes a digital signal processor, a field-programmable gate array connected with the digital signal processor, and an intermediate frequency interface module connected with the field-programmable gate array. The intermediate frequency interface module comprises a digital up-converter and a digital down-converter. The digital signal processor is used for coding and modulating or demodulating and decoding a digital baseband signal. The field-programmable gate array is used for logic programming of the coded and modulated or demodulated and decoded digital baseband signal. The digital up-converter is used for converting the digital baseband signal after logic programming into an intermediate frequency analog signal. The digital down-converter is used for receiving and converting the intermediate frequency analog signal into a digital baseband signal. With the invention, various wireless communication functions can be achieved by loading the software, and in this way, the baseband signal processing platform can have high versatility, a flexible structure, and strong software upgradable and reconfigurable capacities.

The invention discloses a digital up converter capable of performing resampling of random multiples. The digital up converter is used for receiving i and q paths of baseband signals, performing digital up conversion on the two paths of baseband signals and outputting an intermediate frequency signal obtained after processing to a DAC, the digital up converter comprises a forming filter, a resampling module and a frequency mixing module, wherein the resampling module performs resampling on the base bands i and q, can realize up sampling rate conversion of random multiples and can flexibly change the sampling rates of the baseband signals, the adaptability of the sampling rate of the intermediate frequency signal obtained by the frequency mixing module by performing i/q adjustment on the i and q paths of baseband signals is high, which is beneficial for the selection and calibration of the sampling rate of the DAC, moreover the digital up converter does not need to use a CIC filter, a half band filter or a CIC compensation filter, therefore the structure is simple, and the implementation hardware and software is facilitated.