The toolbox also provides functions for generating several widely used aperiodic waveforms:
gauspuls generates a Gaussian-modulated sinusoidal pulse with a specified time, center frequency, and fractional bandwidth. Optional parameters return in-phase and quadrature pulses, the RF signal envelope, and the cutoff time for the trailing pulse envelope.
chirp generates a linear, log, or quadratic swept-frequency cosine signal. An optional parameter specifies alternative sweep methods. An optional parameter,
phi, allows initial phase to be specified in degrees.
To compute 2 seconds of a linear chirp signal with a sample rate of 1 kHz that starts at DC and crosses 150 Hz at 1 second, use:
t = 0:1/1000:2; y = chirp(t,0,1,150);
Plot the spectrogram of the chirp.
gauspuls to plot a 50 kHz Gaussian RF pulse with 60% bandwidth, sampled at a rate of 1 MHz. Truncate the pulse where the envelope falls 40 dB below the peak.
tc = gauspuls('cutoff',50e3,0.6,,-40); t = -tc : 1e-6 : tc; yi = gauspuls(t,50e3,0.6); plot(t,yi)