Swept-frequency cosine

`y = chirp(t,f0,t1,f1)`

y = chirp(t,f0,t1,f1,* 'method'*)

y = chirp(t,f0,t1,f1,

`'method'`

y

` = `

chirp(t,f0,t1,f1,`'`

`quadratic`

`'`

,phi,`'shape'`

`y = chirp(t,f0,t1,f1)`

generates
samples of a linear swept-frequency cosine signal at the time instances
defined in array `t`

, where `f0`

is
the instantaneous frequency at time 0, and `f1`

is
the instantaneous frequency at time `t1`

. `f0`

and `f1`

are
both in hertz. If unspecified, `f0`

is e^{-6} for
logarithmic chirp and 0 for all other methods, `t1`

is `1`

, and `f1`

is `100`

.

`y = chirp(t,f0,t1,f1,`

specifies
alternative sweep method options, where * 'method'*)

`method`

`linear`

, which specifies an instantaneous frequency sweep*f*_{i}(*t*)given by$${f}_{i}(t)={f}_{0}+\beta t$$

where

$$\beta =({f}_{1}-{f}_{0})/{t}_{1}$$

and the default value for

*f*_{0}is 0. β ensures that the desired frequency breakpoint*f*_{1}at time*t*_{1}is maintained.`quadratic`

, which specifies an instantaneous frequency sweep*f*(_{i}*t*) given by$${f}_{i}(t)={f}_{0}+\beta {t}^{2}$$

where

$$\beta =({f}_{1}-{f}_{0})/{t}_{1}{}^{2}$$

and the default value for

*f*_{0}is 0. If*f*_{0}>*f*_{1}(downsweep), the default shape is convex. If*f*_{0 }<*f*_{1}(upsweep), the default shape is concave.`logarithmic`

specifies an instantaneous frequency sweep*f*(_{i}*t*) given by$${f}_{i}(t)={f}_{0}\times {\beta}^{t}$$

where

$$\beta ={\left(\frac{{f}_{1}}{{f}_{0}}\right)}^{\frac{1}{{t}_{1}}}$$

and the default value for

*f*_{0}is 1e^{-6}. Both an upsweep (*f*_{1 }>*f*_{0}) and a downsweep (*f*_{0}>*f*_{1}) of frequency is possible.

Each of the above methods can be entered as `'li'`

, `'q'`

,
and `'lo'`

, respectively.

`y = chirp(t,f0,t1,f1,`

allows
an initial phase * 'method'*,phi)

`phi`

to be specified in degrees.
If unspecified, `phi`

is `0`

.
Default values are substituted for empty or omitted trailing input
arguments.`y`

specifies
the ` = `

chirp(t,f0,t1,f1,`'`

`quadratic`

`'`

,phi,* 'shape'*)

`shape`

of the quadratic swept-frequency signal's
spectrogram. `shape`

is either `concave`

or `convex`

,
which describes the shape of the parabola in the positive frequency
axis. If `shape`

is omitted, the default is convex
for downsweep (

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