echo generator function assignment

2 views (last 30 days)
Sara Ismail-Sutton
Sara Ismail-Sutton on 22 Sep 2020
Answered: Sara Ismail-Sutton on 25 Sep 2020
The task is to given an input column vector (with values between -1 and 1 representing the digitized data), fs the sampling rate, delay to represent the delay of the echo in seconds, amp specifying the amplification of the echo, to add this echo to the original signal after delay seconds.
Other information given is:
  • the output vector will be longer than the input vector when the delay is nonzero- round to the nearest number of points needed to get the delay, as opposted to floor or ceil.
  • if the echo causes some values to be outside of the range -1 to 1, scale the entire vector retaining their relative amplitudes.
Below is the code I have so far. One simple test for the assignment which my code fails is the case:
input= [-0.5; 0; 0.5; 0] and the following parameters: fs = 1, delay: 0.0 seconds, amp = 0.5
For this, I thought the answer should be: [-0.25;0;0.25;0] which my code DOES yield. So I'm wondering if I've mis understood the task also tbh?
Aside from that, for the amplitude rescaling, where i've put 'if norm(input(a)) > 1', from playing around in matlab outside of this function in the live script, I dont think how I've wrote it, in terms of a, some arbitary variable, works? But I'm unsure how to write it without this?
This is what I have wrote so far...
function [output]=echo_gen(input,fs,delay,amp)
N = length(input); % sample lenth
%time = N/fs ;% total time span of audio signaltif
%dt * d=delay
lowerlimit=floor(delay*fs);
M=N+lowerlimit;
%implementingtheecho
length(((lowerlimit+1):M));
length((1:N));
input((lowerlimit+1):M)=amp*input(1:(N));
%condition to check amps and scale relative amps if over
a=[];
if norm(input(a)) > 1
%conditiontoscale
c=max(abs(input))
%solve for the sf s.t c*sf=1
sf=1/c
input=input*sf;
else
output=input;
end
output=input;
end

Answers (1)

Sara Ismail-Sutton
Sara Ismail-Sutton on 25 Sep 2020
bump ! any help really appreciated :)

Categories

Find more on Get Started with MATLAB in Help Center and File Exchange

Products


Release

R2020a

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!