User`s guide

Chirp
5-61
5Chirp
Purpose Generate a swept-frequency cosine (chirp) signal.
Library DSP Sources
Description The Chirp block outputs a swept-frequency cosine (chirp) signal with unity
amplitude and continuous phase. To specify the desired output chirp signal,
you must define its instantaneous frequency function, also known as the output
frequency sweep. The frequency sweep can be linear, quadratic, or logarithmic,
and repeats once every
Sweep time by default. See the following sections of
this reference page for more details:
•“Variables Used in This Reference Page” on page 5-61
•“Setting the Output Frame Status” on page 5-62
•“Shaping the Frequency Sweep by Setting Frequency Sweep and Sweep
Mode” on page 5-62
•“Unidirectional and Bidirectional Sweep Modes” on page 5-63
•“Setting Instantaneous Frequency Sweep Values” on page 5-64
•“Block Computation Methods” on page 5-65
•“Cautions Regarding the Swept Cosine Sweep” on page 5-67
•“Examples” on page 5-68
Variables Used in This Reference Page
Refer to the following list for definitions of variables used in this reference
page.
f
0
Initial frequency parameter (Hz)
f
i
(t
g
) Target frequency parameter (Hz)
t
g
Target time parameter (seconds)
T
sw
Sweep time parameter (seconds)
Initial phase parameter (radians)
Phase of the chirp signal (radians)
f
i
(t) User-specified output instantaneous frequency function (Hz);
user-specified sweep
f
i(actual)
(t) Actual output instantaneous frequency function (Hz); actual
output sweep
y
chirp
(t) Output chirp function
φ
0
ψ t()