since the second differential equations be-
comes an algebraic, or a transcendental equa-
tion
0
= g(t, x, z, 0).
The singular perturbation methods are used
in the analyses of high-gain nonlinear control
systems as well as variable structure sliding
mode control systems.
singular value decomposition (SVD)
useful decomposition method for matrix in-
verse and pseudoinverse problems, including
the least-squared solution of overdetermined
systems. SVD represents the matrix
A in the
form
A = U3
1
2
V , where 3 is a diagonal
matrix whose entries are the singular values
of
A, and U and V are the row and column
eigenvector systems of
A. Any matrix can
be represented in this way. In image pro-
cessing, SVD has been applied to coding, to
image filtering, and to the approximation of
non-separable 2-D point spread functions by
two orthogonal 1-D impulse responses.
singularity
a location in the workspace of
the manipulator at which the robot loses one
or more DOF in Cartesian space, i.e., there
is some direction (or directions) in Cartesian
space along which it is impossible to move
the robot end effector no matter which robot
joints are moved.
singularity function
a function-like op-
eration that is not a proper function in the
analytic sense. This is because it has a point
at which the function or its derivative is infi-
nite or is undefined. In particular, the Dirac
delta function is defined as:
δ(t) =
∞ m = 0
0 otherwise.
Other examples are the step function and the
ramp function.
sintered magnet
magnet made from pow-
dered materials that are pressed together and
then heated in an oven to produce desired
shapes and magnetic properties.
sinusoid
a periodic signal
x(t) =
cos
(ωt + θ) where ω = 2πf with frequency
in hertz.
sinusoidal amplitude modulation
ampli-
tude modulation where the carrier signal is a
sinusoid. See
amplitude modulation
,
carrier
signal
.
sinusoidal coding
parametric speech cod-
ing method based on a speech model where
the signal is composed of sinusoidal compo-
nents having time-varying amplitudes, fre-
quencies and phases. Sinusoidal coding is
mostly used in low bit rate speech coding.
sinusoidal signal
a signal of the form
x(t) = A sin(2πf t + θ)
where
A is the amplitude and θ is the phase
angle.
sinusoidal steady-state response
re-
sponse of a circuit a sine wave input as
t → ∞. The output then has two compo-
nents, a magnitude and a phase, that are the
magnitude and the phase of the transfer func-
tion itself for
s = jω.
sinusoidal–Gaussian beam
electromag-
netic beam in which the transverse field dis-
tribution is describable in terms of sinusoidal
and Gaussian functions.
SiO
2
See
silicon dioxide
.
SIP
See
single in-line packaging
.
SIR
See
signal-to-interference ratio
.
SISD
See
single-instruction stream, single
data stream
.
SISO
See
single-input–single-output
system
.
SISO system
See
single-input–single-
output system
.
SIT
See
static induction transistor
.
c
2000 by CRC Press LLC