
308 ◾ Erwin Hack
object vibrations that induce jitter in the phase value itself. From Equation
(9.15), the signal uncertainty caused by phase step (or object phase) jitter
is obtained according to
β= φ+
Γ
(,)sin ()
.
22
uS
(9.28)
Note that the uncertainty is proportional to the signal modulation
and depends on the phase angle ϕ, even if we assume that the phase step
jitter itself is independent of k and uncorrelated, that is, β= β()
.
Inserting the expression into Equation (9.20) yields
φβ =
β
+δ φ(,)
()
(3 cos(
)
2
2
4
u
u
(9.29)
so that u
N
drops again with
. It is independent of the signal modula-
tion
but varies with the phase ...