THRESHOLD VOLTAGE GENERATOR

摘要

: Threshold circuit for selecting video signals derived -from small stationary and moving objects amidst an abundance of clutter in a harbour area. The threshold voltage generator (1) of -this circuit is suitable for detecting the temporal average .DELTA.P of -the positive peak value and the temporal average .DELTA.N of the negative peak value from the AC component of the applied video voltage (VDC+ VAC) and for generating modified voltages (l+k)(VAC-.DELTA.P) and k(-VAC-.DELTA.N). The modified voltages together with the inverted video voltage are combined -to form the threshold voltage V= VDC+ .DELTA.P+k(.DELTA.P+.DELTA.N) being k times the average peakpeak value above the average peak value of the video voltage, where k is a constant.