diff --git a/dsp_lib.h b/dsp_lib.h
index 10817ac..066b1a4 100644
--- a/dsp_lib.h
+++ b/dsp_lib.h
@@ -43,7 +43,7 @@ class Lowpass {
 template<unsigned int order>
 class Lockin {
     private:
-        double scale;
+        double scale = 1.0;
         phase_t phase = 0;
         Lowpass<std::complex<double>, order> lpf;
     public: