Radar System Engineering

SEC. 3.9] ACTUAL COMPLEX TARGETS 77
and can be described better as a series of flashes. The power in the
higher harmonics decreases only slowly with increasing harmonic number.
Because of these variations of cross section, it has been necessary to
modify the definition of cross section, in order to make at least the
experimental definition unique.
40 db
I’1[:. 39.-Return
power from an AT-I 1 aircraft at 10-cm wavelength as a function of
azimuth angle,
In RL Report A’o. 64-10,1 where a number of measured cross sections
are tabulated, the convention is made that the cross section attains the
tabulated value during one half of a series of time intervals. The signal
is considered as seen in a time interval At if at least once during this
interval it was distinguishable in the noise. The interval length is
1L. B. Linford, D, Williams, V. Josephson,W. Woodcock, and supplementby
L. B. Linford, RL Report No. 64-10, Nov. 12, 1942.