Abstract: The present invention documents a digital channelized receiver for signal intercept applications. A hardware efficient implementation of a uniform filter bank in which the number of filters, K, is greater than the decimation factor, M, is provided. By optimizing the filter bank frequency response, in conjunction with K and M, the proposed invention allows a simple channel arbitration logic to be implemented. In addition, the present invention provides reliable instantaneous frequency measurements and parameter estimates across the desired frequency range while reducing the data processing speed requirements by a factor of M.

Abstract: Disclosed is a method to extract the periodic properties (or Pulse Repetition Intervals (PRIs)) of radar signals whose time-of-arrival at an airborne platform have been time tagged by an Electronic Warfare (EW) receiver. The PRIs are determined using a modified Discrete Fourier Transform (DFT) written as ##EQU1## where k represents the frequency components, the T.sub.i are the individual Time-Of-Arrival (TOA) data values and N is the last TOA value collected.Disclosed are three possible methods of reducing the number of computations involved with the modification of the Discrete Fourier Transform (DFT) equation to facilitate its use with Radar Time-Of-Arrival (TOA) to extract periodic properties of radar signals. This is particularly applicable to radar pulse trains which are interleaved in time and where each individual pulse train may be staggered or jittered in time so that a time domain deinterleaving scheme must be employed.

Abstract: The method provides the capability to estimate the angle-of-arrival (AOA) of radar pulses with respect to a ground or airborne based platform. It utilizes a spectral estimation technique which extracts the periodic properties of radar signals whose time-of-arrivals (TOAs) have been tagged by an Electronic Warfare receiver. The method can be used in a multiple signal environment and can separate and individually measure AOA of emitters that are spatially very close but have incommensurate Pulse Repetition Intervals (PRIs).

Abstract: A technique covered by patent applicaton S.N. 07/672,309 divides power of an input signal to two A/D converters. A processor receives the outputs of the two A/D converters. The input signal is subjected to a known delay .tau. for one of the converters, and both original and delayed signals are sampled simultaneously. Both sampled signals are Fourier transformed and the phase and amplitudes calculated, using the expressions:.phi.(f)=tan.sup.-1 [I(f)/R(f)]A(f)=[R.sup.2 (f)+I.sup.2 (f)].sup.1/2where R(f) and I(f) are respectively the real and imaginary parts of the frequency transform. The phase difference between the original and delayed signals is calculated and an approximation to the true frequency for each peak observed in the amplitude spectrum is estimated using the expression.phi.=2.pi.f.tau.where .tau. is the delay. Herein the input signal is down-converted into two parallel paths with frequencies which differ by f.sub.s /4 where f.sub.s is the sampling rate. The alias boundaries are at multiples of f.