From 5f99d5caddc7b091e6c9de88dee5c68a7f7eeefd Mon Sep 17 00:00:00 2001
From: Filipriec <filippriec@gmail.com>
Date: Thu, 9 Oct 2025 16:09:36 +0200
Subject: [PATCH] hodina 2

---
 hod2/1.m          | 27 +++++++++++++++++++++++++++
 hod2/2.m          |  9 +++++++++
 hod2/DFT_priama.m | 13 +++++++++++++
 hod2/DFT_spatna.m | 13 +++++++++++++
 4 files changed, 62 insertions(+)
 create mode 100644 hod2/1.m
 create mode 100644 hod2/2.m
 create mode 100644 hod2/DFT_priama.m
 create mode 100644 hod2/DFT_spatna.m

diff --git a/hod2/1.m b/hod2/1.m
new file mode 100644
index 0000000..8e6328c
--- /dev/null
+++ b/hod2/1.m
@@ -0,0 +1,27 @@
+% X(k)=1/N \sum_{n=0}^{N-1} x(n)*e^{-j*2*\pi*n*k/N}
+% x(n)=\sum_{n=0}^{N-1} X(k)e^{j*2*\pi*n*k/N}
+
+x = [8,8,8,8,8,8,8,8]
+X = []
+N = length(x)
+
+for k = 0:(N - 1)
+  Xk = 0;
+  for n = 0:(N - 1)
+    Xk = Xk + ( x(n + 1) .* exp(-1j * 2 * pi * n * k / N) );
+  end
+  X(end + 1) =  Xk;
+end
+X = 1/N * X
+
+temp = 1/N * fft(x)
+
+y = [];
+for n = 0:(N - 1)
+  xn = 0;
+  for k = 0:(N - 1)
+    xn = xn + ( X(k + 1) .* exp(1j * 2 * pi * n * k / N) );
+  end
+  y(end + 1) =  xn;
+end
+y
diff --git a/hod2/2.m b/hod2/2.m
new file mode 100644
index 0000000..802bef5
--- /dev/null
+++ b/hod2/2.m
@@ -0,0 +1,9 @@
+% X(k)=1/N \sum_{n=0}^{N-1} x(n)*e^{-j*2*\pi*n*k/N}
+% x(n)=\sum_{n=0}^{N-1} X(k)e^{j*2*\pi*n*k/N}
+
+
+x = [8,8,8,8,8,8,8,8]
+X = DFT_priama(x)
+
+x = DFT_spatna(X)
+
diff --git a/hod2/DFT_priama.m b/hod2/DFT_priama.m
new file mode 100644
index 0000000..e30ff28
--- /dev/null
+++ b/hod2/DFT_priama.m
@@ -0,0 +1,13 @@
+% priama X(k) z x(n)
+function X = DFT_priama(x)
+  X = [];
+  N = length(x);
+  for k = 0:(N - 1)
+    Xk = 0;
+    for n = 0:(N - 1)
+      Xk = Xk + ( x(n + 1) .* exp(-1j * 2 * pi * n * k / N) );
+    end
+    X(end + 1) =  Xk;
+  end
+  X = 1/N * X;
+end
diff --git a/hod2/DFT_spatna.m b/hod2/DFT_spatna.m
new file mode 100644
index 0000000..c78bc1f
--- /dev/null
+++ b/hod2/DFT_spatna.m
@@ -0,0 +1,13 @@
+% spatna x(n) z X(k)
+function x = DFT_spatna(X)
+  x = [];
+  N = length(X);
+  for n = 0:(N - 1)
+    xn = 0;
+    for k = 0:(N - 1)
+      xn = xn + ( X(k + 1) .* exp(1j * 2 * pi * n * k / N) );
+    end
+    x(end + 1) =  xn;
+  end
+end
+