diff --git a/src/fir.rs b/src/fir.rs
index 79ee66a..d1d2ef5 100644
--- a/src/fir.rs
+++ b/src/fir.rs
@@ -1,27 +1,41 @@
 // Finite Impulse response + Decimation
-use crate::utils::ring_buffer::RingBuffer;
-use num_complex::Complex32;
+use crate::{iq_reader::IqChunk, iq_reader::IqSample, utils::ring_buffer::RingBuffer};
 
 pub struct Fir<const N: usize> {
     // Filter coefs
     pub taps: [f32; N],
 
     // Ring Buffer of samples
-    pub history: RingBuffer<Complex32>,
+    pub history: RingBuffer<IqSample>,
 
-    decimation_factor: usize,
+    // Factor of decimation
+    pub decimation_factor: usize,
 
-    // When to keep a sample
-    decimator_counter: usize,
+    // Track decimation
+    pub decimation_index: usize,
 }
 
 impl<const N: usize> Fir<N> {
-    fn new(taps: [f32; N], decimation_factor: usize) -> Self {
+    pub fn new(taps: [f32; N], decimation_factor: usize) -> Self {
         Self {
             taps,
-            history: RingBuffer::new(N),
+            history: RingBuffer::<IqSample>::new(N),
             decimation_factor,
-            decimator_counter: 0,
+            decimation_index: 0,
         }
     }
+
+    pub fn process_chunk(&mut self, chunk: &mut IqChunk) {
+        for iq in chunk.samples.iter_mut() {
+            self.history.push(*iq);
+            let mut y_n = IqSample::default();
+            for k in 0..N {
+                if let Some(sample) = self.history.read_at(k) {
+                    y_n += *sample * self.taps[k];
+                }
+            }
+            *iq = y_n
+        }
+        // TODO: Decimation
+    }
 }
diff --git a/src/main.rs b/src/main.rs
index ac8a70d..af40885 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,4 +1,5 @@
 use crate::agc::Agc;
+use crate::fir::Fir;
 use crate::iq_reader::FileSource;
 use std::error::Error;
 
@@ -10,17 +11,21 @@ mod utils;
 fn main() -> Result<(), Box<dyn Error>> {
     let source = FileSource::new("test.iq", 32769)?;
 
-    // for chunk in source {
-    //     println!("{chunk :?}");
-    // }
+    // TODO: make a clean pipline use like GNU radio with iterators (like chunk.agc(...).fir(...)...)
 
     // 20 MSps
     let mut agc = Agc::new(20_000_000.0, 0.1, 0.001, 100.0);
 
+    // Fir coefs
+    let taps = [1.0; 64];
+    // Fir
+    let mut fir = Fir::<64>::new(taps, 4);
+
     // Apply Auto Gain Control
     for chunk_r in source {
         let mut chunk = chunk_r?;
         agc.process_chunk(&mut chunk);
+        fir.process_chunk(&mut chunk);
     }
 
     Ok(())
diff --git a/src/utils/ring_buffer.rs b/src/utils/ring_buffer.rs
index 67e29b8..3030615 100644
--- a/src/utils/ring_buffer.rs
+++ b/src/utils/ring_buffer.rs
@@ -21,13 +21,13 @@ impl<T: Copy + Default> RingBuffer<T> {
         }
     }
 
-    pub fn write(&mut self, value: T) {
+    pub fn push(&mut self, value: T) {
         self.data[self.head] = value;
         self.head = (self.head + 1) % self.capacity;
         self.size = (self.size + 1).min(self.capacity);
     }
 
-    pub fn read(&mut self) -> Option<T> {
+    pub fn pop(&mut self) -> Option<T> {
         if self.size == 0 {
             return None;
         }
@@ -55,7 +55,7 @@ impl<T: Copy + Default> RingBuffer<T> {
 
     pub fn write_read(&mut self, value: T, delay: usize) -> Option<T> {
         let delayed = self.read_at(delay).copied();
-        self.write(value);
+        self.push(value);
         delayed
     }