diff --git a/amodem/detect.py b/amodem/detect.py
index 31e2db4..006116b 100644
--- a/amodem/detect.py
+++ b/amodem/detect.py
@@ -105,7 +105,7 @@ class Detector(object):
         freq_err = a / (self.Tsym * self.freq)
         last_phase = a * indices[-1] + b
         log.debug('Current phase on carrier: %.3f', last_phase)
-        log.debug('Frequency error: %.2f ppm', freq_err * 1e6)
+        log.debug('Frequency error: %.3f ppm', freq_err * 1e6)
         self.plt.title('Frequency drift: {0:.3f} ppm'.format(freq_err * 1e6))
 
         return amplitude, freq_err