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## Frequency Specification

For some analyses in the frequency domain it is necessary to specify a set of analysis frequencies. The command

freq = lin ( <start> , <stop> , <nrpoints> ) ;
specifies a linear distribution of frequencies, and
freq = log ( <start> , <stop> , <nrpoints> ) ;
a logarithmic distribution. The meaning of the symbols is as follows.
 : expression; start frequency : expression; stop frequency : number of frequency points evaluated for a linear sweep, or the number of frequency points evaluated per decade for a logarithmic sweep
By default, all frequencies are expressed in radians per second. In frequency plots, however, frequency may be expressed in Hertz, but only if the herz flag is set (see Section 9) as follows.
set: hertz;

As an example, the frequency specification for the filter of the previous paragraph might be,

```	freq = log(628.3, 6.283e4, 10);
```
or almost equivalently:
```	freq = log(2 * pi * 100, 2 * pi * 1e4, 10);
```
or
```	set: hertz;
freq = log(100, 1e4, 10);
```

Next: Plot Specification Up: Analysis in the Frequency Previous: Analysis in the Frequency   Contents
2009-06-03