WAVEFORM ENVELOPE DETECTOR Russian patent published in 2004 - IPC

FIELD: communications engineering; waveform envelope detection in signal reception.

SUBSTANCE: proposed waveform envelope detector that can be used to detect waveform envelope in receiving signals at a priori uncertain or unstable signal carrier caused by frequency shift in communication channel due to incorporating provision for autocorrelated processing of signal-noise mixture invariant to signal frequency that considers the fact that signal correlation interval is many times greater than noise correlation interval has first and second multipliers 1, 2, square-root extracting device 3, adder 4, as well as first and second squarers 5, 6; second input of multiplier 1 is coupled with common signal source 7 directly and that of multiplier 2, through phase shifter 8; connected to outputs of multipliers 1 and 2 are first and second low-pass filters, 9 and 10, respectively. Novelty is that bandwidth of both low-pass filters equals half the width of input frequency band; series- connected between output of low-pass filter 9 and input of squarer 5 are third multiplier 11, second adder 12, and third low-pass filter 13; series-connected between output of first low-pass filter 9 and input of squarer 6 are fourth squarer 14, subtracter 15, and fourth low-pass filter 16; series-connected between output of first low-pass filter 9 and subtracting input of subtracter 15 are first memory element 17 and fifth multiplier 18; second low-pass filter 10 is connected to second input of second adder 12 through sixth multiplier 19 with second memory element 20 being inserted between inputs of the latter; bandwidth of third and fourth low-pass filters is inversely proportional to character length minus memory element time constant; common signal source 7 is essentially sine-wave signal generator whose frequency equals central value of signal input frequency band.

EFFECT: enhanced reliability of waveform envelope detection under abnormal conditions.

1 cl, 1 dwg