Usage

s = sig_linsweep(fs, N, range)

Description

S = sig_linsweep(FS, N) returns a sweep of length N with normalized amplitude and sampling rate FS with a perfectly constant magnitude spectrum. It covers all frequencies from 0 to FS/2 and runs from the first to the last sample.

S = sig_linsweep(FS, N, RANGE) returns a sweep of length N with normalized amplitude and a sampling rate of FS and a perfectly constant magnitude spectrum. The signal covers all frequencies from 0 to FS/2. The sweep starts at sample RANGE(1) and ends at sample RANGE(2), i.e., RANGE must be an array with two positive elements with 0 < RANGE(1) < RANGE(2) <= N. A tail is encountered before and after the actual sweep range.

EXAMPLE 1: Create a perfect sweep and display its spectrogram:

fs = 44100;                 % sampling rate of 44100 Hz
s = sig_linsweep(fs, 4*fs)  % 4 secs sweep
spectrogram(s, 256, 128, 256, fs, 'yaxis');
sound(s,fs);

EXAMPLE 2: Create a perfect sweep in a range:

fs = 44100;                 % sampling rate of 44100 Hz
s = sig_linsweep(fs, 4*fs, [fs+1,2*fs]); % 4 secs with sweep
                                         % from fs+1 to 2*fs
spectrogram(s, 256, 128, 256, fs, 'yaxis');
sound(s,fs);

To create a continuous measurement stimulus, you have to stack as many length N periods together as you need. Considering the sampling rate fs, you have to repeat the sweep period t*fs/N times to get a signal length of t seconds. Make sure t*fs/N is an integer.