diff --git a/assertions.prs b/assertions.prs
index 158d2fb..67fc359 100644
--- a/assertions.prs
+++ b/assertions.prs
@@ -5,6 +5,6 @@ FileSystemUsage = <file-system-usage @path string @size int>.
 # This assertion publishes a dataspace that proxies assertions with
 # an exception for <Observe …> which is pulsed every periodSec.
 # The pulse resolution is no more than one millisecond.
-Pulse = <pulse @periodSec double @proxy #!any>.
+Pulse = <pulse @periodSec float @proxy #!any>.
 
 XmlTranslation = <xml-translation @xml string @pr any>.
diff --git a/src/schema/assertions.nim b/src/schema/assertions.nim
index afdbd85..f8cf39c 100644
--- a/src/schema/assertions.nim
+++ b/src/schema/assertions.nim
@@ -4,7 +4,7 @@ import
 
 type
   Pulse* {.preservesRecord: "pulse".} = object
-    `periodSec`*: float64
+    `periodSec`*: BiggestFloat
     `proxy`* {.preservesEmbedded.}: Value
 
   XmlTranslation* {.preservesRecord: "xml-translation".} = object