diff --git a/Storage/Disk/DigitalPhaseLockedLoop.cpp b/Storage/Disk/DigitalPhaseLockedLoop.cpp
index fc1dcd214..66ef529ac 100644
--- a/Storage/Disk/DigitalPhaseLockedLoop.cpp
+++ b/Storage/Disk/DigitalPhaseLockedLoop.cpp
@@ -61,8 +61,10 @@ void DigitalPhaseLockedLoop::post_phase_offset(int phase, int offset) {
 		total_divisor += multiple;
 		total_spacing += offset;
 	}
-	window_length_ = total_spacing / total_divisor;
-	window_length_ = std::max(std::min(window_length_, clocks_per_bit_ + tolerance_), clocks_per_bit_ - tolerance_);
+	if(total_divisor) {
+		window_length_ = total_spacing / total_divisor;
+		window_length_ = std::max(std::min(window_length_, clocks_per_bit_ + tolerance_), clocks_per_bit_ - tolerance_);
+	}
 
 	int error = phase - (window_length_ >> 1);
 
diff --git a/Storage/Tape/Parsers/TapeParser.hpp b/Storage/Tape/Parsers/TapeParser.hpp
index c46152337..422788ba7 100644
--- a/Storage/Tape/Parsers/TapeParser.hpp
+++ b/Storage/Tape/Parsers/TapeParser.hpp
@@ -160,7 +160,7 @@ template <typename SymbolType> class PLLParser:
 		/// Instantiates a new parser with the supplied @c tape.
 		PLLParser(int clock_rate, int clocks_per_bit, int tolerance) :
 			clock_rate_(clock_rate),
-			pll_(clocks_per_bit, tolerance, 3),
+			pll_(clocks_per_bit, tolerance, 15),
 			input_bit_counter_(0),
 			input_pattern_(0),
 			was_high_(false) {