Page 316 - Electrical Engineering Dictionary

for a fixed value of G t , where S 11 , S 22 , S 12 , required passband gain.
and S 21 are the scattering parameters for the
G ripple = G max − G min
device.

p outmax
= 10 log 10
gain coefficient factor multiplying dis- p incident

tance in a formula for the exponential am- p outmin
− 10 log 10
plitude or intensity growth of a wave in an p incident
unsaturated amplifying medium.
gain saturation reduction in gain that oc-
gain compensation this deals with the curs when the intensity of a laser field de-
assumption in motion estimation in inter- pletes the population inversion.
frame coding that illumination is spatially
and temporally uniform. Under these as- gain switching rapid turn-on of the gain in
sumptions, the monochrome intensities b(zt) a laser oscillator for the purpose of producing
and b(zt − τ) of two consecutive frames are a large output pulse.
related by b(zt) and b(z − D,t − τ) where τ
is the time between two frames, D is the two- gain–bandwidth product for amplifiers
dimensional translation vector. Often this as- based on a voltage-feedback op-amp, in-
sumption about uniform illumination is not creasing the closed-loop gain causes a pro-
correct. In some situations, a multiplicative portional decrease to the closed-loop band-
factor called gain is used to change the inten- width; thus the product of the two is a con-
sity. This is called gain compensation. This stant. This constant is called the gain–
results in estimating D using gradient-type bandwidth product, and is a useful figure-of-
algorithms to minimize the square of the pre- merit for the performance of the op-amp.
diction error.
gain-guidedlaser laserinwhichthemode
gain focusing focusing or collimation of fields are confined in the transverse direction
an electromagnetic beam by the profile of the by the profile of the gain.
gain; gain guiding.
gain-shape vector quantization (GSVQ)
See shape-gain vector quantization.
gain guided laser diode electrically
pumped semiconductor laser in which the
gain-transfer measurement method
mode fields are confined in the transverse di-
common antenna gain measurement scheme
rection by the profile of the gain.
in which the absolute gain of the antenna un-
der test is determined by measuring its gain
gain medium medium for which an out-
relative to a gain standard (i.e., antenna with
put electromagnetic wave has more power
accurately known gain).
than the corresponding input, essential for
laser operation. GaInN/AlInN rapidly evolving semicon-
ductor heterostructure system with ability to
gain ripple difference between the emit light in the green and blue regions of the
maximum gain (G max = 10 log [p outmax / spectrum for long-lifetime LEDs and lasers.
10
p incident ]) and the minimum gain across the
band (G min = 10 log [p outmin /p incident ]), Galerkin’s method in an integral equa-
10
expressed in decibels. The band edges are tion technique used to solve a numerical elec-
usually defined as the highest and lowest fre- tromagnetic problem, the method in which
quencies within a contiguous band of inter- the expansion and testing functions are the
est at which the gain equals the minimum same.

c
2000 by CRC Press LLC