Page 168 - Fundamentals of Radar Signal Processing

transmitted frequency F on the reflectivity measurements.
t
To understand the role of transmitted frequency, it is necessary to deal with
the radar signal while it is still at the radar frequency F. If the development
t
from Eq. (2.110) to Eq. (2.124) is repeated without demodulating the signals to
baseband and the range variation is considered, the RF version of Eq. (2.124)
can be obtained:

(2.128)

Now consider the Fourier transform of with respect to the time (range)
variable t. Using simple properties of Fourier transforms gives

(2.129)

Figure 2.30 provides a pictorial interpretation of this equation under the
assumption that the transmitted waveform x(t) is a narrowband waveform. In
this case,

FIGURE 2.30 Pictorial interpretation of Eq. (2.130), illustrating the spectral
sampling effect of a narrowband radar pulse.

(2.130)