Method and apparatus for adaptively suppressing unwanted lobes in a compressed coded radar signal

Claim 3

The method according to claim 1 comprising the further step of: reiterating steps (a)-(d), seriatim, for the peak amplitude of the main lobes remaining in said coded signal after the subtraction dictacted in step (d) has been effected.

Claim 4

The method according to claim 1 wherein said pulse train generating step further comprises: detecting said peak amplitude signal in a threshold detector having a first threshold setting; synchronizing said pulse train with the output of said threshold detector; comparing the amplitude of said coded signal with a reference signal; and then adjusting the amplitude of said pulse train in accordance with the results of said comparison.

Claim 5

The method according to claim 3 wherein said pulse generating step further comprises: prior to said amplitude comparing step, gating said coded signal in synchronism with said pulse train.

Claim 6

Apparatus for adaptively eliminating unwanted lobes in a compressed, coded signal, which comprises: a threshold detector for receiving said coded signal, said detector having its threshold set to detect lobes in said coded signal which exceed a predetermined amplitude level; a pulse generator, connected to and driven by the output of said threshold detector, for generating a train of pulses synchronized with the lobes in said coded signal which are of peak amplitude; means, connected to said pulse generator, for adjusting the amplitude of each pulse in said train to said peak amplitude; means, connected to the output of said amplitude adjusting means, for encoding each pulse in said pulse train using the same coding scheme employed to generate said coded signal; a matched filter, connected to the output of said encoding means, for compressing each encoded pulse in said pulse train; and means for subtracting said compressed pulses from said coded signal, thereby to eliminate lobes in said coded signal associated with the lobes detected by said threshold detector.

Claim 7

Apparatus for adaptively eliminating unwanted lobes in a compressed, coded signal, which comprises: a threshold detector for receiving said coded signal, said detector having its threshold set to detect lobes in said coded signal which exceed a predetermined amplitude level; a pulse generator, connected to and driven by the output of said threshold detector, for generating a train of pulses synchronized with the lobes in said coded signal which are of peak amplitude; means, connected to said pulse generator, for adjusting the amplitude of each pulse in said train to said peak amplitude; means, connected to the output of said amplitude adjusting means, for encoding each pulse in said pulse train using the same coding scheme employed to generate said coded signal; a matched filter, connected to the output of said encoding means, for compressing each encoded pulse in said pulse train; and means for subtracting said compressed pulses from said coded signal, thereby to eliminate lobes in said coded signal associated with the lobes detected by said threshold detector.

Claim 8

The apparatus according to claim 5 wherein said amplitude adjusting means further comprises: a source of a reference potential; an amplitude comparison stage having a first and a second input, said reference potential source being connected to said first input; gating means, connected to and synchronized by the output of said pulse generator, for gating said coded signal into the second input of said amplitude comparison stage; and a variable amplifier having its gain-setting input connected to the output of said amplitude comparison stage, for adjusting the amplitude of each pulse in said pulse train.

Claim 9

The apparatus according to claim 6 wherein said subtracting means further comprises: an inverting stage connected to the output of said matched filter; and a summing stage having a first input connected to the output of said inverting stage and a second output connected to the sOurce of said coded signal.

Claim 10

The apparatus according to claim 7 further comprising a delay element interposed between said summing stage and the source of said coded signal, said delay element having a delay equal to the combined delay of the circuit elements interposed between said source of the coded signal and the first input of said summing stage.

Claim 11

Apparatus for adaptively eliminating unwanted lobes in a compressed coded signal S, where S S1 + S2 + . . . Si + . . . Sn, and S1 > S2 > . . . Si > . . . Sn, which comprises: (n - 1) signal cancelling stages, the ith one of said (n - 1) stages comprising: a threshold detector receiving as its input the coded signal from the preceding (i - 1)th stage, said detector having its threshold level set to detect lobes in said coded signal which exceed a predetermined amplitude level E, where Si 1 > E > Si; a pulse generator, connected to and driven by the output of said threshold detector, for generating a train of pulses synchronized with the lobes in said coded signal which are of peak amplitude; means, connected to said pulse generator, for adjusting the amplitude of each pulse in said train to said peak amplitude; means, connected to the output of said amplitude adjusting means, for encoding each pulse in said pulse train using the same coding scheme employed to generate said coded signal; a matched filter, connected to the output of said encoding means, for compressing each encoded pulse in said pulse train; and means for subtracting said compressed pulses from said coded signal, thereby furnishing the coded signal input to the following (i + 1)th stage.

Claim 12

Apparatus for adaptively eliminating unwanted lobes in a compressed coded signal S, where S S1 + S2 + . . . Si + . . . Sn, and S1 > S2 > . . . Si > . . . Sn, which comprises: (n - 1) signal cancelling stages, the ith one of said (n - 1) stages comprising: a threshold detector receiving as its input the coded signal from the preceding (i - 1)th stage, said detector having its threshold level set to detect lobes in said coded signal which exceed a predetermined amplitude level E, where Si 1 > E > Si; a pulse generator, connected to and driven by the output of said threshold detector, for generating a train of pulses synchronized with the lobes in said coded signal which are of peak amplitude; means, connected to said pulse generator, for adjusting the amplitude of each pulse in said train to said peak amplitude; means, connected to the output of said amplitude adjusting means, for encoding each pulse in said pulse train using the same coding scheme employed to generate said coded signal; a matched filter, connected to the output of said encoding means, for compressing each encoded pulse in said pulse train; and means for subtracting said compressed pulses from said coded signal, thereby furnishing the coded signal input to the following (i + 1)th stage.