An Interleaved Radio Frequency Digital-to-Analog Converter (RF DAC) suitable for use in cellular base stations and optimized to give both a wide RF tuning range and a wide RF bandwidth is disclosed. The RF DAC uses two levels of interleaving, the first providing a direct conversion path from Base Band (BB) to RF, and the second providing a variable interleaving factor through the use of summation to optimize the output bandwidth as a function of the RF center frequency. Digital Interpolation, including an arbitrary sample rate conversion filter, allows the RF DAC to operate from a wide range of possible BB sample rates and the DAC sample rate is a fixed ratio of the RF center frequency. As a result, the spurious outputs from the RF DAC are in known locations that are relatively easy to filter out, minimizing the frequency planning tasks required for a complete RF system design.

A receiving circuit includes a receiver configured to receive a signal, a detector configured to detect arrival of a reception signal based on a signal received by the receiver, a buffer configured to store therein data corresponding to the reception signal, a demodulation processor configured to demodulate data to be supplied, and a controller configured to store the data corresponding to the reception signal in the buffer when the detector does not detect the arrival of the reception signal, and to supply the data stored in the buffer to the demodulation processor when the detector detects the arrival of the reception signal.

A digital down converter with an equalizer translates an ADC output signal to a low frequency spectral region, followed by decimation. All operations of correction of the processed signal are carried out with a reduced sampling rate compared with sampling rates of the prior art. Equalization is performed only in a frequency pass band of the down converter. The achieved reduction of the required computation resources is sufficient to enable the down converter with equalization to operate in a real time mode.

Power amplification system for radio frequency communications, comprising a input port of an input radio frequency signal, an output port of an output radio frequency signal; a digital predistortion unit operatively interposed between the input port and the output port and quadrature modulation correction means operatively interposed between the digital predistortion unit and between at least one of the input port and the output port.

An RF receiver comprising: an RF signal processing unit for receiving an RF signal, wherein the RF signal processing unit comprises a dynamically reconfigurable RF filter for filtering the RF signal; an analog-to-digital converter for converting the filtered RF signal to a digital signal; and a digital signal processing unit for processing the digital signal to provide at least one channel; wherein the digital signal processing unit is adapted to adjust a respective transfer function of at least one said channel when the RF filter is reconfigured, to at least partially compensate a change in the transfer function of the RF filter.

A radio receiving apparatus includes: a radio receiving circuit that frequency-converts a radio signal frequency-modulated with a baseband signal into an intermediate frequency signal; a frequency component detecting circuit that samples the intermediate frequency signal using an over-sampling frequency that is variable and detects a plurality of frequency components in the intermediate frequency signal; and a control circuit that detects a data rate of the baseband signal that is included in the intermediate frequency signal, detects a signal level of the intermediate frequency signal, and determines and sets the over-sampling frequency for the frequency component detecting circuit in accordance with the data rate of the baseband signal and the signal level of the intermediate frequency signal.

A system for transmitting modulation in a narrow band radio frequency channel include a first signal generator configured to modulate a first signal containing data for transmission to provide a primary signal, the primary signal utilizing a higher order modulation technique than would otherwise be permissible if the first signal is transmitted separately. The system further includes a second signal generator, configured to modulate a second signal containing a pulse signal to provide a second signal, wherein the peak signal level of the second signal results in a measurement of the bandwidth of the first signal at a higher signal level and a narrower bandwidth, and a digital signal processor (DSP), which receives and combines the primary signal and the secondary signal and outputs a combined modulated signal for further digital-to-analog conversion, processing and transmission in a radio frequency band.

An integrated analog to digital converting and digital to analog converting (ADDA) RF transceiver for satellite applications, configured to replace conventional analog RF down and up conversion circuitry. The ADDA RF transceiver includes one of more ADCs, DSPs, and DACs, all on a single ASIC. Further, the circuitry is to be radiation tolerant for high availability and reliability in the ionizing radiation environment present in the space environment.

A receiver includes a quadrature mixer to perform frequency conversion to convert a radio-frequency signal into an I signal and a Q signal that have a 90 phase difference from each other and a surface acoustic wave (SAW) device to perform phase conversion on the I signal and the Q signal that are output from the quadrature mixer. In the SAW device, when represents a phase rotation amount of the I signal, represents a phase rotation amount of the Q signal, and n is an integer, (+90n36035.1)(+90+n360+35.1) or (90+n36035.1)(90+n360+35.1).

The system and method for ameliorating the effect of close-in user equipment up to a point where the user equipment itself limits the performance. The system and method utilizes a digital filter in front of the LASER modulator being applied to the LASER. Additionally, total power detectors may be used at input to prevent unwanted signals from overloading stages in front of the LASER. The system further includes a scanning receiver capable of scanning and analyzing the wide-band signal received from user equipment in the uplink direction.