diff --git a/tools/JFCalibrationPerfTest.cpp b/tools/JFCalibrationPerfTest.cpp
index 6ea3fe7c..6793441d 100644
--- a/tools/JFCalibrationPerfTest.cpp
+++ b/tools/JFCalibrationPerfTest.cpp
@@ -21,23 +21,12 @@
 void test_pedestal(Logger &logger) {
     size_t nframes = 5000;
     DiffractionExperiment x(DetectorGeometry(1));
+    x.Mode(DetectorMode::Conversion);
 
     std::vector<uint16_t> data(nframes * RAW_MODULE_SIZE);
 
-    x.Mode(DetectorMode::Conversion);
-    double mean = 1000.0;
-    double stddev = 50.0;
-
-    // Predictable random number generator
-    std::mt19937 g1(5423);
-    std::normal_distribution<double> distribution(mean, stddev);
-
-    for (size_t i = 0; i < nframes * RAW_MODULE_SIZE; i++) {
-        double number = distribution(g1);
-        if (number < 20) number = 20;
-        if (number > 16300) number = 16300;
-        data[i] = number;
-    }
+    for (size_t i = 0; i < nframes * RAW_MODULE_SIZE; i++)
+        data[i] = 3000 + (i % 881) + (i % 557);
 
     JFPedestalCalc calc_cpu(x);
     auto start_time = std::chrono::system_clock::now();