A method for operating a radio frequency communications system includes, while operating a first radio frequency communications device in a calibration mode, for each setting of a plurality of settings of a programmable gain amplifier in a receiver of the first radio frequency communications device configured in a zero-intermediate frequency mode of operation, generating an estimate of a DC offset in each of a plurality of digital samples received from an analog circuit path including the programmable gain amplifier, and storing in a corresponding storage element, a compensation value based on the estimate.

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 wideband receiver system comprises a wideband analog-to-digital converter (ADC) module and a digital frontend (DFE) module. The wideband ADC is configured to concurrently digitize a band of frequencies comprising a plurality of desired channels and a plurality of undesired channels. The DFE module is coupled to the digital in-phase and quadrature signals. The DFE module is configured to select the plurality of desired channels from the digitized band of frequencies, and generate an intermediate frequency (IF) signal comprising the selected plurality of desired channels and having a bandwidth that is less than a bandwidth of the band of frequencies, where the generation comprises frequency shifting of the selected plurality of desired channels. The IF signal may be a digital signal and the DFE is configured to output the IF signal via a serial or parallel interface.

A method and terminal device for executing a radio application is disclosed. The method for executing a radio application is a method for executing a radio application independent of a modem in a terminal device, comprising the steps of: communicating with each other using a reconfigurable radio frequency interface (RRFI) by a unified radio application (URA), which operates on a radio computer of the terminal device, and a radio frequency (RF) transceiver, which operates in a radio platform on the radio computer; and supporting, by the RRFI, at least one service among a spectrum control service, a power control service, an antenna management service, a transmission/reception chain control service, and a radio virtual machine protection service.

Various embodiments provide for systems and methods for signal conversion of one modulated signal to another modulated signal using demodulation and then re-modulation. According to some embodiments, a signal receiving system may comprise an I/Q demodulator that demodulates a first modulated signal to an in-phase (“I”) signal and a quadrature (“Q”) signal, an I/Q signal adjustor that adaptively adjusts the Q signal to increase the signal-to-noise ratio (SNR) of a transitory signal that is based on a second modulated signal, and an I/Q modulator that modulates the I signal and the adjusted Q signal to the second modulated signal. To increase the SNR, the Q signal may be adjusted based on a calculated error determined for the transitory signal during demodulation by a demodulator downstream from the I/Q modulator.

According to one aspect, an embodiment radio frequency receiver device comprises an input interface configured to receive a radio frequency signal of a given type and convert same into an electric signal, a detector configured to detect at least one voltage level in the electric signal, a pulse generator configured to generate at least one pulse train representative of the voltage levels detected, and a processing unit configured to determine the type of the radio frequency signal from the at least one pulse train.

Radio-frequency (RF) receivers having bandpass sigma-delta analog sigma analog-to-digital converters (ADC) designed to digitize signals in the RF domain are described. Such bandpass ADCs utilize one or more of the following techniques to enhance noise immunity and reduce power consumption: generation of in-phase (I) and quadrature (Q) paths in the digital domain, n.sup.th order resonant bandpass filtering with n>1, and signal sub-sampling in an i.sup.th Nyquist zone with i>1. Compared to RF receivers in which the I and Q paths are generated in the analog domain, these RF receivers exhibit higher IRRs because they are not susceptible to in-phase/quadrature (IQ) mismatch. Using n.sup.th order resonant bandpass filtering with n>1 attenuates unwanted image tones. The bandpass ADC-based RF receivers described herein exhibit enhanced immunity to noise, achieving for example image rejection ratios (IRR) in excess of 95 dB.

An electromagnetic wave transmission device according to the present invention includes: a transmission unit that has, in voltage-current characteristics, a local maximum value and a local minimum value located on a higher voltage side than the local maximum value and transmits an electromagnetic wave indicating a modulation signal; and a modulation unit which modulates an acquired digital signal to the modulation signal using first voltage values of two or more levels in a first voltage region, which is equal to or greater than a voltage of the local maximum value and is equal to or less than a voltage of the local minimum value, and a second voltage value in a second voltage region, which is less than the voltage of the local maximum value, and a third voltage value in a third voltage region, which is on a higher voltage side than the voltage of the local minimum value. A first signal which transits to any one voltage value of the first voltage values from any voltage value in the first voltage region via the second voltage value and a second signal which transits to the any one voltage value from the any voltage value via the third voltage value are the same signals. The modulation unit selects, out of the first signal and the second signal, the signal having a smaller total transition potential difference.

According to one aspect, an embodiment radio frequency receiver device comprises an input interface configured to receive a radio frequency signal of a given type and convert same into an electric signal, a detector configured to detect at least one voltage level in the electric signal, a pulse generator configured to generate at least one pulse train representative of the voltage levels detected, and a processing unit configured to determine the type of the radio frequency signal from the at least one pulse train.

High-performance filter bank channelizers are provided. In one embodiment, a heterodyne signal shifts an input spectrum of the input signal by an offset between input and output centers, and operates at a high input sample rate. In another embodiment, the channelizer includes an input commutator receiving and commutating an input signal, an M-path polyphaser filter in communication with the commutator, and an M-path inverse discrete Fourier transform module processing outputs of the polyphaser filter, wherein the M-path polyphaser filter introduces a plurality of phase rotations in a time domain resulting in a workload reduction for a processor on which the channelizer is implemented. Still other embodiments includes a resampling channelizer, a half-band filter, and a cascaded half-band filter.