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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.
`<`*start*`>` |
: |
expression; start frequency |

`<`*stop*`>` |
: |
expression; stop frequency |

`<`*nrpoints*`>` |
: |
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
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2009-06-03