how to depict the histogram envelop in matlab

[firephenix405]

matlab plot enveloppe histogram

I generate a sequence of random variable in Matlab, and sketch its histogram using function hist(), but now I want to sketch its histogram envelop, not only histogram,

how should I do??

 

[amraldo]

d u mean by envelope the frequency curve?

 

[firephenix405]

right, contour curve

 

[amraldo]

u can use the histc as follows
[N,C]=histc(A,n);
%N is an array of histogram amplitudes
%C is an array of corresponding centers
%A is the array of input data
%n is the number of segments of the histogram
%i.e. n =length(N) or length(C)
plot(C,N);