Pulse descriptor words (PDW) are measured properties of detected RF pulses. PDWs are often utilized for radar sensor characterization, identification, and emulation. Pulse measurements are typically provided as an option on high-SWaP, high-cost laboratory test equipment or as custom FPGA firmware which is not easily scalable to multiple SDR/RF platforms. gr-pdw is an out-of-tree (OOT) module for GNU Radio developed by GTRI that performs pulse detection and PDW generation. The intention is that gr-pdw provides the ability for any commercial-off-the-shelf (COTS) SDR to perform PDW measurements. Currently it is capable of measuring pulse width, power, frequency, and time-of-arrival (ToA) along with noise power. gr-pdw also provides blocks for writing PDWs to a log file and controlling the flowgraph parameters remotely over a network connection. Testing has been performed with a USRP B210 in both laboratory and field settings with measurements comparable to currently used PDW generators. Blocks have been prototyped in Python with plans to port them to C++ for improved performance in high pulse-rate scenarios. GTRI plans to open source this OOT after initial capabilities have been fully tested and implemented. This paper presents gr-pdw theory of operation, descriptions of block functions, and test results.