Python script with Head block runs too long before exiting

The attached file is run as a thread of a larger project. I run this as a script and not a GUI.

 

The script waits for a real time of 15 or 45 seconds to begin execution of the flowgraph. The Head block is set at 157680 which is 13.14 seconds at 12000 samples/sec. The Head block feeds a Wave file sink.

 

The program works as it should properly storing data in the wave file except for the issue below.

 

The issue is that I expect the script (flowgraph) to cease execution at 13.14 seconds. This is based on my understanding of the operation of a Head block. However, it continues to run(?) for another approximately 3+ secs before exiting. Needless to say this creates huge timing issues for the rest of the program.

 

Any ideas?

 

Jim

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