diff --git a/library/RTP_Emulation.ttcn b/library/RTP_Emulation.ttcn
index e4a3029..10cf683 100644
--- a/library/RTP_Emulation.ttcn
+++ b/library/RTP_Emulation.ttcn
@@ -89,14 +89,14 @@
 	RTP.send(t_RTP_Send(g_rtp_conn_id, RTP_messages_union:{rtp:=rtp}));
 	/* increment sequence + timestamp for next transmit */
 	g_tx_next_seq := g_tx_next_seq + 1;
-	g_tx_next_ts := g_tx_next_ts + (g_tx_samplerate_hz mod (1000 mod g_tx_duration_ms));
+	g_tx_next_ts := g_tx_next_ts + (g_tx_samplerate_hz / (1000 / g_tx_duration_ms));
 }
 
 function f_main() runs on RTP_Emulation_CT
 {
 	var Result res;
 
-	timer T_transmit := 1000.0/int2float(g_tx_duration_ms);
+	timer T_transmit := int2float(g_tx_duration_ms)/1000.0;
 	var RTP_RecvFrom rx_rtp;
 	var template RTP_RecvFrom tr := {
 		connId := ?,