eldo_user

Hand Selection
Setting Up An Analysis
Pole Zero Analysis
After these steps, a further choice between the resulting roots is offered. A prompt asks:
Do you agree with the Selected POLES [Yes/No]?
If the selected poles and zeros are Ok, enter Y and the analysis continues. If only a certain
number of poles and zeros are required, enter N and the following prompt is displayed:
Poles selection by their index in INCREASING order
Enter a negative index to end the selection.
Select Index
A prompt asks for the specification of which poles are to be included in the final transfer
function. The selection is made via the index to the values—the index being the first number
that appears in the tables above. Once the values to use have been chosen, the selection is
terminated by entering a negative number. The process is then repeated for zeros.
Note
Ensure that the selections are made in increasing integer order including the negative
terminator, otherwise required values may be lost.
The remaining set of poles and zeros are printed, followed by another table showing the
difference between the actual and the now-approximated model, swept in frequency and giving
both the magnitude (dB) and the phase (degree) differences. For example:
Hz dB’s Error Degrees Error
1.000000E+01 6.525140E-04 1.020462E-02
1.000000E+02 6.201058E-04 1.096881E-02
1.000000E+03 5.805557E-04 1.102087E-02
1.000000E+04 5.806112E-04 1.107192E-02
1.000000E+05 5.791327E-04 3.599889E+02
1.000000E+06 5.815470E-04 1.444244E-02
1.000000E+07 1.179731E-03 4.588650E-02
1.000000E+08 5.953287E-02 3.609858E-01
1.000000E+09 4.490041E+00 2.134625E+00
FNS Model
The reduced circuit is now modeled as an S-domain transfer function (for example, an FNS
device in Eldo syntax) which can replace the original circuit with the introduced approximations
for AC and small-signal analysis—this can be very useful for developing complex designs,
enabling the replacement of even a complex block with its equivalent model and great
simplification of simulation of the higher-level system. The output format is as follows:
Eldo® User's Manual, 15.3 235