diff --git a/impl/src/main.c b/impl/src/main.c
index 98d6052..55b4b62 100644
--- a/impl/src/main.c
+++ b/impl/src/main.c
@@ -301,8 +301,7 @@ int main(void)
 			}
 
 			if(n_rf_samples == 0) {
-				struct timespec ts_1ms = {0, 1000000};
-				nanosleep(&ts_1ms, NULL);
+				fsleep(1e-3);
 				continue;
 			}
 
diff --git a/impl/src/sdr/sdr.c b/impl/src/sdr/sdr.c
index c818d9e..00156ab 100644
--- a/impl/src/sdr/sdr.c
+++ b/impl/src/sdr/sdr.c
@@ -6,10 +6,10 @@
 #include <complex.h>
 #include <math.h>
 #include <string.h>
-#include <time.h>
 #include <assert.h>
 
 #include "config.h"
+#include "utils.h"
 
 #include "sdr.h"
 
@@ -141,10 +141,9 @@ static result_t stop_streaming(sdr_ctx_t *ctx)
 			return OK;
 	}
 
-	struct timespec ts_1ms = {0, 1000000};
 	while(hackrf_is_streaming(ctx->hackrf) == HACKRF_TRUE) {
 		puts("wr");
-		nanosleep(&ts_1ms, NULL);
+		fsleep(1e-3);
 	}
 
 	ctx->status = SDR_STATUS_IDLE;
@@ -342,9 +341,9 @@ result_t sdr_receive(sdr_ctx_t *ctx, float complex *samples, size_t *nsamples, l
 
 result_t sdr_flush_tx_buffer(sdr_ctx_t *ctx)
 {
-	while(!ctx->tx_done) {
-		struct timespec ts_1ms = {0, 1000000};
-		nanosleep(&ts_1ms, NULL);
+	// block until all samples have been transmitted
+	while(!ctx->tx_done || (get_hires_time() < (ctx->tx_start_time + ctx->tx_duration))) {
+		fsleep(1e-3);
 	}
 
 	return OK;