Suppose that you have two (discrete time) signals x[n] and y[n] where 
.
. You can make them "unity energy" by using the following formulas:
Now these two signals x1[n] and y1[n] have equal power (=1) and you can correlate them as you've described.
Also, have a look at the following code:
clearvars; clc; close all;
% creation of signals
N=1024;
n=0:N-1;
x=sin(2*pi*(2^-7).*n);
y=2*sin(2*pi*(2^-7).*n+pi/4);
% justify its power
x1=x/sqrt(mean(x.^2));
y1=y/sqrt(mean(y.^2));
%plots
figure;
subplot(2,1,1);
plot(x); hold on;
plot(y); grid on; zoom on;
legend('x', 'y');
subplot(2,1,2);
plot(x1); hold on;
plot(y1); grid on; zoom on;
legend('x1', 'y1');
