How extracted envelop signal in matlab 2013

[y,fs]=wavread(‘fil.wav’) Db=mag2db(y) How find envelop of db??!!

Answer 1

[Star Strider]

Use the hilbert function, specifically:

DbEnv = abs(hilbert(Db));

Example —

t = 0:0.01:5;                                                       % Create Data
s = sin(2*pi*t) .* cos(2*pi*10*t);                                  % Create Data
psenv = abs(hilbert(s));                                            % Upper Envelope
nsenv = abs(hilbert(-s));                                           % Lower Envelope

figure
plot(t, s, 'LineWidth',1.5)
hold on
plot(t,  psenv, '-r', 'LineWidth',2)
plot(t, -nsenv, '-g', 'LineWidth',2)
hold off
grid
legend('Signal','Upper Envelope','Lower Envelope', 'Location','N')

.