Lockheed Martin Corporation

Michael J Walsh

Byron Tietjen

Lindsay C Peterson

Paul T Martellock

A direct radio frequency complex analog to digital converter (CADC) device provides corrective factors including a plurality of time-interleaved low speed ADCs, wherein each ADC corresponds to an ADC channel. A phase corrective factor is calculated for each ADC channel. An amplitude corrective factor is calculated for each ADC channel. The phase and amplitude corrective factors are applied to complex bandpass filter coefficients to produce filter coefficients corrected for the phase and amplitude imbalances between ADCs. Digital output of each ADC channel is filtered by a complex bandpass filter using the corrected filter coefficients to produce corrected in-phase and quadrature output at baseband. Harmonics produced by the ADCs are canceled by filtering ADC outputs in a first bandpass filter to an intermediate frequency such that the harmonics fall outside the band of interest, a second filter is applied to attenuate the harmonic and produce a signal output at baseband.

Direct input radio frequency complex analog to digital converter with corrective factors

A system comprising an radio frequency (RF) signal input; a plurality of time-skewed, undersampled analog to digital converters (ADCs); a plurality of complex finite input response (FIR) filters in parallel, wherein each complex FIR filter receives the output beam and/or band provided by the plurality of ADCs and generates a corresponding output beam of a given frequency.

System and method for wideband direct sampling and beamforming using complex analog to digital converter

An analog to digital converter device including: an input to receive a radio frequency (RF) signal; a plurality of delay elements coupled in series to the input, wherein each element has an output configured to provide the RF signal with a temporal delay corresponding to a different number of the delay elements; a sample rate reduction system having a plurality of inputs each being coupled to a corresponding one of the delay element outputs, and configured to sample the delayed RF signals and provide M-sample outputs, each of the M-sample outputs being sampled at a reduced sampling rate equal to the sampling rate divided by M, M being an integer sample rate reduction value; and an Norder complex bandpass filter coupled to the sample rate reduction system, the complex bandpass filter being configured to filter each of the M-sample outputs to obtain a plurality of complex baseband signals.

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Baldwinsville, NY, United States of America

Michael J Walsh