Apparatus for detecting echo signals

Claim 1

An apparatus for detecting echo signals produced by reflection of pulses transmitted with a given time period T and a given pulse width τ, characterized by means (SPF) for determining, with a resolution of t/M wherein t is essentially equal to the pulse width τ and M is at least three, signal positions within each of a predetermined number N of consecutive, constantly changing equidistant intervals with the period T and the length t, and for producing, for each signal position ascertained, a secondary signal (PI) in a corresponding resolution interval of t/M, and means (DL1-DL(M-1), VK1-VKM, SUM) for currently summing up the secondary signals produced in the last N·M resolution intervals with such weighting that the individual secondary signals in a set of M resolution intervals are given in a weight which depends on their distance from the central resolution interval of the set, said weight decreasing with increasing distance, wherein said means for determining signal positions comprise a delay circuit (DL) and a comparator (K1) connected therewith, said comparator producing a binary output signal (3) which changes condition every time the delayed signal (2) and the non-delayed signal (1) assume identical value, and that said signal (3) is supplied to a trigger circuit (MV1, MV2), to which clock pulses (CI) are also supplied and which is arranged in such a way that it issues, with each shift in one direction of the output signal of the comparator, a position pulse (PI) beginning at the first clock pulse after the shift and having a duration of one clock pulse period, said position pulse forming said secondary signal.

Claim 2

An apparatus for detecting echo signals produced by reflection of pulses transmitted with a given time period T and a given pulse width τ, characterized by means (SPF) for determining, with a resolution of t/M wherein t is essentially equal to the pulse width τ and M is at least three, signal positions within each of a predetermined number N of consecutive, constantly changing equidistant intervals with the period T and the length t, and for producing, for each signal position ascertained, a secondary signal (PI) in a corresponding resolution interval of t/M, and means (DL1-DL(M-1), VK1-VKM, SUM) for currently summing up the secondary signals produced in the last N·M resolution intervals with such weighting that the individual secondary signals in a set of M resolution intervals are given in a weight which depends on their distance from the central resolution interval of the set, said weight decreasing with increasing distance, wherein said means for determining signal positions comprise a delay circuit (DL) and a comparator (K1) connected therewith, said comparator producing a binary output signal (3) which changes condition every time the delayed signal (2) and the non-delayed signal (1) assume identical value, and that said signal (3) is supplied to a trigger circuit (MV1, MV2), to which clock pulses (CI) are also supplied and which is arranged in such a way that it issues, with each shift in one direction of the output signal of the comparator, a position pulse (PI) beginning at the first clock pulse after the shift and having a duration of one clock pulse period, said position pulse forming said secondary signal.