function [] = angel(fn, str)
% a helpless angel
% angel(filename, plot-title)

[id, fval, voltages] = textread(fn, '%n%f%n');
voltages = voltages - mean(voltages);

[N, trash]=size(voltages);

voltfft = fft(voltages);

FS = 30;
Ts = 1/FS;
DELTAF = 1 / ( N * Ts );
FREQ = 0:DELTAF:FS/2;
FREQ = FREQ';
plot(FREQ(1:N/2), abs(voltfft(1:N/2)));
title(str);
pause;

plot(id, voltages);
title(str);