Here we discuss the type of power information desired from a
system model. Since the objective is to find weak points in the
system power flow, only power extremes are considered. Power
extremes are the cross talk and signal levels obtained when
the worst possible combinations of device states and input
power levels are assumed.
...The weakest 1 arriving at the
detection point under all conditions from all possible paths
to the point is defined as #math266#P1min, and similarly, the
strongest 0 is defined as #math267#P0max. Proper
device operation can be ensured if the following relations
are met:
#math268#
|
P0max ;SPMlt; PS2 ;SPMlt; PD ;SPMlt; PS1 ;SPMlt; P1min.
|
(1) |
122
verbatim152#
123
It is also
desirable to have information about #math269#Pmax, the maximum
power level that can occur at the inputs to a given device. A
power detector may provide erroneous results when the power
of a logic 1 arriving at a detection point is too large;
that is, when #math270#Pmax exceeds PD by some large
amount. A second and more important reason for computing #math271#Pmax is that it makes the major contribution to
cross talk, as discussed below. Knowledge of the power
triple #math272#P0max, P1min, and #math273#Pmax
at each device in a system permits the tracking of power
levels throughout the entire system.