[q,nd] = max(10*log10(P)); - this is used in spectrogarm . but can anyone tell me what is this ? and how length of q and nd is calculated?

[q,nd] = max(10*log10(P));

Answer 1

[Star Strider]

It transforms an argument of power ‘P’ to decibels, and returns in ‘q’ the first instance of the maximum power in decibels, and in ‘nd’ returns the index of that value.

[Biswajit Ojha]

thank u for ur ans. but how their length can be calculated theoretically?

[Star Strider]

Why do you say "the value of an array B"? Normally an array is multiple values, not a single value. Did you really mean to say "the values of an array B"?

What are the dimensions of A and B? How does B change in your loop? Is B a global variable that is declared global both in that routine, and in Sysmodel()??? And you change the value of the global variable B in Sysmodel? If B is declared only in your code you posted, then it will have the same value every time, unless you've intentionally left out critical parts of your code.

[Walter Roberson]

sz = size(P);
dim = find(sz ~= 1);
sz(dim) = 1;

q and nd will be the size indicated by sz.

If P is a 2D array (not a vector), then q and nd will each be row vectors with as many columns as P had columns.