68 results about "Digital up converter" patented technology

Digital Transceiver (DTRX) usable in a radio communications systems for transmitting and receiving digital base-band signals, wherein the DTRX (300) comprises: at least one digital up-converter (DUC) (310) for transmitting digital base-band signals and at least one digital down-converter for receiving digital base-band signals. In one aspect of the teachings disclosed herein the DUC (310) comprises at least two over-sampling units (314, 315), at least one quadrature modulation unit (340), and at least one time-discrete sigma delta band-pass modulator (318). The digital down-converter comprises at least one quadrature demodulation unit (360), at least two decimator units (356,357), and at least two sub-sampling units (354, 355). The digital base-band signal comprises an in-phase component (I-signal) and a quadrature component (Q-signal).

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 (36I, 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.

A module for an active antenna system for receiving and transmitting radio signals sealed in a housing. It comprises a power connector placed at the outside of the housing for supplying the module with supply power; at least one micro radio for receiving / sending digital radio signals having a digital down-converter / a digital up-converter and a control signal converter. The micro radio converts the digital radio signals to analogue RF (radio frequency) signals and vice versa and is connected to the internal bus. At least one antenna element is connected to the micro radio and an internal data bus for the exchange of digital radio data and control data is connected to micro radio and hub. By placing two or more modules next to each other on a frame these modules form an active antenna system.

A system and method for enhancing the performance of wideband digital RF transport systems is disclosed, which enables the transport of different bandwidth segments on a plurality of wideband channels by selecting an optimal clock sample rate for each bandwidth segment to be transported. Thus, the bandwidth segments are proportionally allocated so that an optimum amount of bandwidth can be transported at the serial bit rate. As one example, a system for enhancing the performance of a wideband digital RF transport system is disclosed, which includes a transmit unit, a receive unit, and an optical transmission medium connected between the transmit unit and the receive unit. The transmit unit includes a plurality of wideband RF analog signal inputs coupled to a plurality of analog-to-digital, digital down-converter (A / D DDC) devices. Notably, the sample rate of each A / D DDC device is determined by a respective sample clock. The digitized wideband RF segments at the outputs of the A / D DDC devices are combined and converted to a frame structure, converted to serial form, and transmitted on the optical transmission medium to the receive unit. A light detector device in the receive unit detects the serial bit stream on the optical transmission medium, the serialized frames are converted back to the original frame format, and the original digitized wideband RF segments are reconstructed. Each digitized wideband RF segment is coupled to a respective D / A digital up-converter (D / A DUC) device associated with a particular wideband RF signal input on the transmit side. Notably, the output sample rate of each D / A DUC device is determined by a respective sample clock, which provides the same sample rate as that of the associated A / D DDC device in the transmit unit. The sample rate of each A / D DDC device (and associated D / A DUC device) is pre-selected so that the transmission medium can transport the optimum amount of RF bandwidth at the given serial bit rate.

The invention discloses a short-wave radio frequency digital processing module which mainly comprises a receiving radio frequency analog front end, a receiving radio frequency digital front end and an emission submodule, wherein the receiving radio frequency analog front end comprises a harmonic filter, a broadband low-noise amplifier with automatic gain control (AGC) and a low-pass filter; the receiving radio frequency digital front end comprises an analog / digital (A / D) conversion circuit, a digital down converter (DDC), a direct digital frequency synthesizer (DDS) and a digital signal processor (DSP); and the emission submodule comprises a digital / analog (D / A) conversion circuit, a digital up converter (DUC), a DDS and a DSP. The short-wave radio frequency digital processing module of the invention can simplify the design structure of a shortwave radio station, reduces the types of radio stations, improves the service life of the digital shortwave radio station, and reduces the input cost of users.

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 invention provides an antenna arraying full-spectrum correlated combining system based on a broadband signal frequency domain and aims to provide a frequency domain based arraying system capable of saving hardware computing resources and overcoming phase ambiguity. The technical scheme includes that the antenna arraying full-spectrum correlated combining system is implemented according to that an A / D (analog / digital) module is used for sampling inputted broadband medium-frequency analog signals; obtained digital medium-frequency signals are subjected to sampling clock full-period delay by a delay module according to N antenna signal time delay estimation values fed back by a correlated combining module, then subjected to frequency conversion by a DDC (digital down converter ) module, polyphase decomposition by an analysis module to obtain M falling-rate narrow-band branches with uniform frequency domain ranges, polyphase correlation, time delay estimation and feedback, fractional time delay correction and polyphase combining by a correlated combining module, polyphase synthesis by a synthesis module, and finally are outputted to a demodulation receiver through a DUC (digital up converter) module and a D / A (digital / analog) module. The antenna arraying full-spectrum correlated combining system based on the broadband signal frequency domain solves the problem of phase ambiguity through integer multiples of sampling clock delay and fractional delay compensation.

A radio frequency (RF) receiver is provided, comprising an antenna, a low noise amplifier, a down converter, a first analog to digital converter (ADC), a second ADC, a digital up converter. The antenna receives an RF signal, and the LNA coupled to the antenna amplifies the RF signal. The down converter, coupled to the LNA, down converts the RF signal to generate an in-phase baseband signal and a quadrature baseband signal. The first ADC, coupled to the down converter, digitizes the in-phase baseband signal to an in-phase digital signal. The second ADC, coupled to the down converter, digitizes the quadrature baseband signal to a quadrature digital signal. The digital up converter, coupled to the first and second ADCs, up converts the in-phase digital signal and quadrature digital signal to generate an intermediate frequency (IF) signal.

The invention discloses a calibration system and method for the amplitude-phase error of a receiving channel of a spaceborne DBF (Digital Beam Forming) network. The system comprises a calibration signal generating module, a calibration signal transmitting module, a receiving channel and calibration interface module, and a calibration algorithm execution module, wherein the calibration algorithm execution module comprises an amplitude-phase error estimator and a calibration factor generator; the calibration signal generating module comprises an orthogonal pseudo random code block generator and a BPSK (Binary Phase Shift Keying) modulator; the calibration signal transmitting module comprises a digital up converter, a DA inverter, an analog up converter and a calibration feed source; the calibration signal generating module is connected with the calibration signal transmitting module; and the calibration algorithm execution module is connected with the receiving channel and calibration interface module. The system and the method provided by the invention have the advantages of strong real-time performance, high precision and high stability, and save satellite resources.

An RF transmission circuit, complex digital synthesizer and MRI apparatus are intended to enhance the stability of signal quantity and reduce the cost, wherein a complex digital synthesizer generates reference carrier frequency signal data directly in the digital domain, RF envelope mixers combine the resulting data and RF envelope signal data in the digital domain, and a digital frequency up-converter up-converts the resulting signal data in the digital domain and converts into an analog RF pulse signal.

Antenna system connectable to a base station, the antenna system comprising a digital radio unit connectable to at least one antenna element, wherein the digital radio unit comprises: at least one micro radio for receiving / sending digital radio signals having a digital down-converter / a digital up-converter and a digital signal converter. The at least one micro radio converts the digital radio signals to analogue RF (radio frequency) signals and vice versa. The at least one micro radio has at least one hub for processing digital radio signals and control signals and for routing said digital radio signals and control signals via at least one serial link and at least one interface. The at least one serial link is provided between the at least one hub and the at least one micro radio.

A signal intermediate frequency transmitting device of a multimode mobile communication system comprises a parameter automatic configuration module, an interpolation filter module, a digital up-converter module and a D / A converter. The parameter automatic configuration module is used for generating frequency points needed by the digital up-converter module and filter coefficients and the interpolation rate needed by the interpolation filer module according to different communication systems; the interpolation filter module is used for conducting interpolation and filter according to the filter coefficients and the interpolation rate; the digital up-converter module is used for up converting signals output by the interpolation filter module to the frequency points and outputting the signals to the D / A converter; the D / A converter is used for conducting digital-to-analogue conversion on the signals output by the digital up-converter module. The signal intermediate frequency transmitting device is suitable for LTE-CDMA / WCDMA / TD-SCDMA / GSM communication systems. The interpolation filter module comprises a four-level filter. The digital up-converter module comprises a digital frequency mixer. The signal intermediate frequency transmitting device can support the multiple communication systems, the structure of the system is simplified, the size of the device is small, and the device is low in manufacturing cost.