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 circuity is to be radiation tolerant for high availability and reliability in the ionizing radiation environment present in the space environment.

The present application describes systems and methods of performing self-interference cancellation. According to an embodiment, the method sends a transmit signal through a circulator to substantially isolate the transmit signal from a receiver, with at least a portion of the transmit signal entering a receive path towards the receiver. The method also generates a reflected signal from an antenna. The reflected signal is at substantially less power than an incident power to the antenna. The reflected signal includes a transmitter carrier signal and a transmitter noise. The method also routes a received signal from the antenna to the receiver, and routes the reflected signal through a phase shifter in the receive path. Further, the method combines the reflected, phase shifted transmitter noise with the received signal in the receive path to cancel the portion of the transmit signal that entered the receive path towards the receiver.

A digital filter for interpolation or decimation and a device incorporating the digital filter is disclosed. The digital filter includes a filter block, a first transformation circuit coupled to the filter block and an input stream coupled to provide input values to a component selected from the filter block and the first transformation circuit. The filter block includes a pair of sub-filters having respective transformed coefficients, the respective transformed coefficients of a first sub-filter of the pair of sub-filters being symmetric and the respective transformed coefficients of a second sub-filter of the pair of sub-filters being anti-symmetric. The first transformation circuit is coupled to perform a first transformation; the filter block and the first transformation circuit together provide suppression of undesired spectral images in final outputs of the digital filter.

Methods and systems for generating a digital representation of the amplitude and phase of a bandpass signal are disclosed. The methods comprise filtering the bandpass signal with a bandpass filter, generating the real and imaginary parts of the complex analytic signal with a quadrature hybrid, determining the amplitude of the complex analytic signal by adding an even power-law transform of the real and imaginary parts of the complex analytic signal, and determining the phase of the complex analytic signal by comparing the real and imaginary parts of the complex analytic signal to zero and comparing an even power-law transform of the real and imaginary parts of the complex analytic signal to each other. Analog to digital converters and methods of converting complex analytic signals to digital signals are also disclosed.

An apparatus for reducing an amplitude imbalance and a phase imbalance between an in-phase signal and a quadrature signal is provided. The in-phase signal and the quadrature signal are based on a radio frequency receive signal. The apparatus includes an imbalance estimation module configured to generate a first correction signal related to a first phase shift, and to generate a second correction signal related to a second phase shift. Further, the apparatus includes a first digital-to-time converter configured to receive the first correction signal and a local oscillator signal. The first digital-to-time converter is further configured to supply a first replica of the local oscillator signal for a first mixer generating the in-phase signal, wherein the first replica of the local oscillator signal has the first phase shift with respect to the local oscillator signal. The apparatus further includes a second digital-to-time converter configured to receive the second correction signal and the local oscillator signal. The second digital-to-time converter is further configured to supply a second replica of the local oscillator signal for a second mixer generating the quadrature signal, wherein the second replica of the local oscillator signal has the second phase shift with respect to the local oscillator signal.

The embodiments of the present application disclose a method and device for sending and receiving an optical signal. The method for sending an optical signal comprises: performing serial-to-parallel conversion on a data signal to be transmitted to obtain an I path data sequence, a Q path data sequence and a PPM path data sequence which are in parallel; performing mPQ-encoding on the I path data sequence, the Q path data sequence and the PPM path data sequence to obtain an I path and a Q path of an mPQ-encoded digital signal; shaping the I path and the Q path of the mPQ-encoded digital signal by Nyquist-filtering to obtain an I path and Q path of a filtered digital signal; performing digital-to-analog conversion on the I path and the Q path of the filtered digital signal and mapping the converted I path and Q path onto an optical carrier to obtain a target optical signal and send the same. By applying the embodiments of the present application, spectral efficiency loss in optical communication can be reduced or even eliminated while power efficiency is increased.

The present application describes a computer-implemented method for configuring a front end including receiving a first signal and a second signal containing interference; characterizing the receive channel using the first tone; processing the compensated first signal using an infinite impulse response filter based on the characterized receive channel to generate an interference cancelling signal; and coupling the interference cancelling signal to the second signal to generate an interference cancelled receive signal. The present application also describes a computer-implemented apparatus for a front end.

A digital filter for interpolation or decimation and a device incorporating the digital filter is disclosed. The digital filter includes a filter block, a first transformation circuit coupled to the filter block and an input stream coupled to provide input values to a component selected from the filter block and the first transformation circuit. The filter block includes a pair of sub-filters having respective transformed coefficients, the respective transformed coefficients of a first sub-filter of the pair of sub-filters being symmetric and the respective transformed coefficients of a second sub-filter of the pair of sub-filters being anti-symmetric. The first transformation circuit is coupled to perform a first transformation; the filter block and the first transformation circuit together provide suppression of undesired spectral images in final outputs of the digital filter.

Methods and systems for generating a digital representation of the amplitude and phase of a bandpass signal are disclosed. The methods comprise filtering the bandpass signal with a bandpass filter, generating the real and imaginary parts of the complex analytic signal with a quadrature hybrid, determining the amplitude of the complex analytic signal by adding an even power-law transform of the real and imaginary parts of the complex analytic signal, and determining the phase of the complex analytic signal by comparing the real and imaginary parts of the complex analytic signal to zero and comparing an even power-law transform of the real and imaginary parts of the complex analytic signal to each other. Analog to digital converters and methods of converting complex analytic signals to digital signals are also disclosed.

Apparatuses (and methods of manufacturing same), systems, and methods concerning polyphase digital filters are described. In one aspect, an apparatus is provided, including at least one pair of subfilters, each having symmetric coefficients, and a lattice comprising two adders and feedlines corresponding to each of the at least one pair of subfilters, each having symmetric coefficients. In one aspect, the apparatus is a polyphase finite impulse response (FIR) digital filter, including an interpolator and a decimator, where each of the interpolator and the decimator have at least one pair of subfilters, each having symmetric coefficients, and a lattice comprising two adders and feedlines corresponding to each of the at least one pair of subfilters, each having symmetric coefficients.