diff --git a/src/Makefile.am b/src/Makefile.am
index a8473b1..3d1240d 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -21,6 +21,7 @@ SIMPLEAUDIO_SRC = \
 	simpleaudio.h		\
 	simpleaudio_internal.h	\
 	simpleaudio.c		\
+	simple-tone-generator.c \
 	simpleaudio-pulse.c	\
 	simpleaudio-sndfile.c
 
diff --git a/src/Makefile.in b/src/Makefile.in
index aad6866..165b7b1 100644
--- a/src/Makefile.in
+++ b/src/Makefile.in
@@ -56,8 +56,8 @@ am__installdirs = "$(DESTDIR)$(bindir)"
 PROGRAMS = $(bin_PROGRAMS)
 am__objects_1 = baudot.$(OBJEXT)
 am__objects_2 = fsk.$(OBJEXT)
-am__objects_3 = simpleaudio.$(OBJEXT) simpleaudio-pulse.$(OBJEXT) \
-	simpleaudio-sndfile.$(OBJEXT)
+am__objects_3 = simpleaudio.$(OBJEXT) simple-tone-generator.$(OBJEXT) \
+	simpleaudio-pulse.$(OBJEXT) simpleaudio-sndfile.$(OBJEXT)
 am_minimodem_OBJECTS = minimodem.$(OBJEXT) $(am__objects_1) \
 	$(am__objects_2) $(am__objects_3)
 minimodem_OBJECTS = $(am_minimodem_OBJECTS)
@@ -171,6 +171,7 @@ SIMPLEAUDIO_SRC = \
 	simpleaudio.h		\
 	simpleaudio_internal.h	\
 	simpleaudio.c		\
+	simple-tone-generator.c \
 	simpleaudio-pulse.c	\
 	simpleaudio-sndfile.c
 
@@ -262,6 +263,7 @@ distclean-compile:
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/baudot.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/fsk.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/minimodem.Po@am__quote@
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/simple-tone-generator.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/simpleaudio-pulse.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/simpleaudio-sndfile.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/simpleaudio.Po@am__quote@
diff --git a/src/simple-tone-generator.c b/src/simple-tone-generator.c
new file mode 100644
index 0000000..6a3ca33
--- /dev/null
+++ b/src/simple-tone-generator.c
@@ -0,0 +1,57 @@
+/*
+ * simple-tone-generator.c
+ *
+ * Copyright (C) 2011 Kamal Mostafa <kamal@whence.com>
+ *
+ * NO LICENSE HAS BEEN SPECIFIED OR GRANTED FOR THIS WORK.
+ *
+ */
+
+
+#include <math.h>
+#include <strings.h>
+#include <assert.h>
+
+#include "simpleaudio.h"
+
+
+/* "current" phase state of the tone generator */
+static float sa_tone_cphase = 0.0;
+
+void
+simpleaudio_tone_reset()
+{
+    sa_tone_cphase = 0.0;
+}
+
+void
+simpleaudio_tone(simpleaudio *sa_out, float tone_freq, size_t nsamples_dur)
+{
+#define    TONE_GEN_BUFSIZE	(10*48000)	// FIXME
+    float buf[TONE_GEN_BUFSIZE];
+
+    assert ( nsamples_dur <= TONE_GEN_BUFSIZE );
+
+    if ( tone_freq != 0 ) {
+
+	float wave_nsamples = 48000.0 / tone_freq;	// FIXME rate
+
+	size_t i;
+	for ( i=0; i<nsamples_dur; i++ ) {
+	    buf[i] = sinf( M_PI*2.0*( i/wave_nsamples + sa_tone_cphase) );
+	    buf[i] /= 2.0;	// normalize (for pulseaudio?) */
+	}
+
+	sa_tone_cphase
+	    = fmodf(sa_tone_cphase + (float)nsamples_dur/wave_nsamples, 1.0);
+
+    } else {
+
+	bzero(buf, nsamples_dur*sizeof(float));
+	sa_tone_cphase = 0.0;
+
+    }
+
+    assert ( simpleaudio_write(sa_out, buf, nsamples_dur) > 0 );
+}
+
diff --git a/src/simpleaudio.h b/src/simpleaudio.h
index cd5c1c8..677b717 100644
--- a/src/simpleaudio.h
+++ b/src/simpleaudio.h
@@ -55,4 +55,15 @@ void
 simpleaudio_close( simpleaudio *sa );
 
 
+/*
+ * simpleaudio tone generator
+ */
+
+void
+simpleaudio_tone_reset();
+
+void
+simpleaudio_tone(simpleaudio *sa_out, float tone_freq, size_t nsamples_dur);
+
+
 #endif