diff --git a/src/codec2/mod.rs b/src/codec2/mod.rs
index f16ef03107c504ada4ded04aacd26f0acdcafb4e..a4c61663ee7a69277abb6642b8a8fac5402358f0 100644
--- a/src/codec2/mod.rs
+++ b/src/codec2/mod.rs
@@ -144,7 +144,7 @@ pub struct Fsk<I: Iterator<Item = Complex>> {
 
 impl<I: Iterator<Item = Complex>> Fsk<I> {
     pub fn new(iq_iter: I) -> Self {
-        const P: i32 = 10;
+        const P: i32 = 5;
         const FS: i32 = 9600 * P;
 
         let internal = unsafe { fsk_create_hbr(FS, 9600, M, P, N_SYM, -1, 0) };