diff --git a/gstlal/python/reference_psd.py b/gstlal/python/reference_psd.py
index f47758d2c4e3d5415984560115a41deba91727fc..0b62def7dac982688be6ea9961bcd96c3a3f7ed0 100644
--- a/gstlal/python/reference_psd.py
+++ b/gstlal/python/reference_psd.py
@@ -477,7 +477,7 @@ class PSDFirKernel(object):
 		#
 
 		data = psd.data.data / 2
-		sample_rate = 2 * int(round(psd.f0 + len(data) * psd.deltaF))
+		sample_rate = 2 * int(round(psd.f0 + (len(data) - 1) * psd.deltaF))
 
 		#
 		# remove LAL normalization