diff --git a/plugins/channelrx/demoddatv/leansdr/math.h b/plugins/channelrx/demoddatv/leansdr/math.h
index 3a6d84a7c..bb1c98397 100644
--- a/plugins/channelrx/demoddatv/leansdr/math.h
+++ b/plugins/channelrx/demoddatv/leansdr/math.h
@@ -45,6 +45,11 @@ struct complex
         im = re * c.im + im * c.re;
         re = tre;
     }
+    inline void operator-=(const complex<T> &x)
+    {
+        re-=x.re;
+        im-=x.im;
+    }
     inline void operator*=(const T &k)
     {
         re *= k;
@@ -58,6 +63,11 @@ complex<T> operator+(const complex<T> &a, const complex<T> &b)
     return complex<T>(a.re + b.re, a.im + b.im);
 }
 
+template<typename T>
+complex<T> operator -(const complex<T> &a, const complex<T> &b) {
+    return complex<T>(a.re - b.re, a.im - b.im);
+}
+
 template <typename T>
 complex<T> operator*(const complex<T> &a, const complex<T> &b)
 {