C-Netz: Add low pass filter to eliminate high frequency noise

This improves the FSK decoding quite allot, especially with SDR.
2017-02-12 07:31:29 +01:00
parent 290b365d67
commit 4de1e0188d
2 changed files with 8 additions and 2 deletions
--- a/src/cnetz/cnetz.h
+++ b/src/cnetz/cnetz.h
@@ -88,6 +88,7 @@ typedef struct cnetz {

 	/* dsp states */
 	enum dsp_mode		dsp_mode;		/* current mode: audio, "Telegramm", .... */
+	filter_t		lp;			/* low pass filter to eliminate noise above 5280 Hz */
 	fsk_fm_demod_t		fsk_demod;		/* demod process */
 	double			fsk_deviation;		/* deviation of FSK signal on sound card */
 	sample_t		fsk_ramp_up[256];	/* samples of upward ramp shape */