TransferFunction implemented for series biquad

src/filter/seriesbiquad.rs

@@ -1,14 +1,11 @@
-
 use super::*;
 
 use super::biquad::Biquad;
 use anyhow::{bail, Result};
 
-
 #[derive(Clone, Debug)]
 #[cfg_attr(feature = "python-bindings", pyclass)]
 
-
 /// Series of biquads that filter sequentially on an input signal
 ///
 /// # Examples
@@ -109,7 +106,16 @@ impl Filter for SeriesBiquad {
         Box::new(self.clone())
     }
 }
-
+impl<'a, T: AsArray<'a, Flt>> TransferFunction<'a, T> for SeriesBiquad {
+    fn tf(&self, fs: Flt, freq: T) -> Ccol {
+        let freq = freq.into();
+        let mut res = self.biqs.first().unwrap().tf(fs, freq);
+        for i in self.biqs.iter().skip(1) {
+            res = &res * i.tf(fs, freq);
+        }
+        res
+    }
+}
 
 #[cfg(test)]
 mod test {