PEAK POSITION DETECTOR

The position of a peak in a digital signal is determined by a circuit consisting of a finite impulse response filter constructed in accordance with either the expression (1+z.sup.-1)(1+z.sup.-2) (1-z.sup.-5) or the simplified expression (1+z.sup.-1) (1-z.sup.-3), where z is the z transform function and the index indicates the number of clock intervals in each delay. The practical realization of the filter for applying these expressions to the input signal involves the use of three (for the first expression) or two (for the second expression) delay circuits in series. The output of the filter is a differentiated signal, the zero crossing point of which represents the desired peak position. This crossing point is detected in an interpolation circuit which linearly interpolates the location of such point to a fraction of a clock interval or pixel.