FREQ2

Frequency List, Alternate Form 2

Description: Defines a set of frequencies to be used in the solution of frequency response problems by specification of a starting frequency, final frequency, and the number of logarithmic increments desired.

Format:

Example:

Field	Definition	Type	Default
SID	Set identification number.	Integer > 0	Required
F1	First frequency.	Real > 0.0	Required
F2	Last frequency.	Real > 0.0, F2 > F1	Required
NF	Number of logarithmic intervals.	Integer > 0	1

Remarks:

1. FREQi entries must be selected with the Case Control command FREQUENCY = SID.
2. The units for F1 and DF are cycles per unit time.
3. The frequencies defined by this entry are given by:

   

   where,

   

   and,

   i = 1, 2, …, (NF + 1)

   In the example above, the list of frequencies will be 1.0, 10.0, 100.0, 1000.0, and 10000.0 cycles per unit time.

4. The DFREQ model parameter specifies the threshold for the elimination of duplicate frequencies. Duplicate frequencies will be ignored if

   

   where DFREQ is defaulted to 1.0x10^-5 and and are the maximum and minimum solution frequencies of the combined FREQi entries. (See Section 5, Parameters, for more information on DFREQ.)