User Guide

Chapter 6 Analog behavioral modeling
184
The DELAY property increases the group delay of the
frequency table by the specified amount. The delay term
is particularly useful when an EFREQ or GFREQ device
generates a non-causality warning message during a
transient analysis. The warning message issues a delay
value that can be assigned to the part’s DELAY property
for subsequent runs, without otherwise altering the table.
The output of the device depends on the analysis being
done. For DC and bias point, the output is simply the zero
frequency magnitude times the value of EXPR. For AC
analysis, EXPR is linearized around the bias point (similar
to EVALUE and GVALUE parts). The output for each
frequency is then the input times the gain of EXPR times
the value of the table at that frequency. For transient
analysis, the value of EXPR is evaluated at each time
point. The output is then the convolution of the past
values of EXPR with the impulse response of the
frequency response. These rules follow the standard
method of using Fourier transforms. We recommend
looking at one or more of the references cited in
Frequency-domain device models
on page 6-181 for more
information.
Note The table’s frequencies must be in order from lowest to highest.
DELAY group delay increment; defaults to 0
if left blank.
R_I table type; if left blank, the frequency
table is interpreted in the (input
frequency, magnitude, phase)
format; if defined with any value
(such as YES), the table is interpreted
in the (input frequency, real part,
imaginary part) format.
MAGUNITS units for magnitude where the value
can be DB (decibels) or MAG (raw
magnitude); defaults to DB if left
blank.
PHASEUNITS units for phase where the value can
be DEG (degrees) or RAD (radians);
defaults to DEG if left blank.
Pspug.book Page 184 Wednesday, November 11, 1998 1:14 PM