초록 ▼

Significant features of interest of each pulse shape, amplitude and time of occurrence characteristics, are preserved in a detection circuit that (1) employs a tapped delay line as part of means for deriving a pedestal signal at the predicted current level of an input signal to the delay line, the l

Significant features of interest of each pulse shape, amplitude and time of occurrence characteristics, are preserved in a detection circuit that (1) employs a tapped delay line as part of means for deriving a pedestal signal at the predicted current level of an input signal to the delay line, the level of the pedestal signal being determined by extrapolating the slope and level of a running segment of the past history of the input signal level to the delay line, (2) subtracts the derived pedestal signal level from the actual level of an applied input signal, comprised of pulses superimposed on an unknown and variable background signal, to produce a difference level, (3) indicates the occurrence of a pulse by this difference level being at least equal to a threshold level, (4) selectively applies the applied input signal as the input signal to the delay line when the difference level is below the threshold level, and (5) selectively applies the pedestal signal as an input signal to the delay line when the difference level is at least equal to the threshold level.

대표청구항 ▼

Pulse detection apparatus responsive to an applied analog time signal comprising an unknown and variable level, relatively low-frequency background components on which is superimposed one or more relatively high-frequency pulse components, in which the significant features of interest of each pulse

Pulse detection apparatus responsive to an applied analog time signal comprising an unknown and variable level, relatively low-frequency background components on which is superimposed one or more relatively high-frequency pulse components, in which the significant features of interest of each pulse are characterized by its shape, amplitude and time of occurrence characteristics; said apparatus comprising: first means including storage means responsive to a running segment of given duration of the immediate past history of the level of an input signal to said first means for deriving a pedestal signal at a predicted present level of said input signal to said first means said predicted present level of the input signal to the first means being a function of the D.C. level and the slope of said running segment, switch means operative in a first switch position thereof for applying said analog time signal as said input signal to said first means and operative in a second switch position thereof for applying said pedestal signal as said input signal to said first means, second means for subtracting said pedestal signal from the actual present level of said analog time signal to derive a difference signal, third means responsive to the level of said difference signal with respect to a given threshold level for deriving a status signal indicative of whether or not the level of said difference signal is equal to or exceeds said given threshold level, fourth means coupled between said third means and said switch means for maintaining said switch means in its second switch position whenever the level of said difference signal is equal to or exceeds said threshold level and for maintaining said switch means in its first switch position whenever the level of said difference signal is below said threshold level, and output means responsive to said difference signal and said status signal for deriving one or more outputs from the pulse detection apparatus which are indicative of at least one of said characteristics of each pulse. The pulse detection apparatus defined in claim 1, wherein said analog time signal is comprised of a stream of successive pixels of a scanned image field in which each individual pixel corresponds to a different particular location within the image field, each pulse having a duration equal to a plurality of successive pixels; wherein said output means includes fifth means for deriving a first output signal having a value during each one of said plurality of successive pixels which is indicative of the value of said difference signal during that pixel and sixth means for deriving a second output signal having a value during each one of said successive pixels which is indicative of the particular location corresponding to that pixel.