Update README.md

README.md

@@ -16,6 +16,8 @@ On the Raspberry Pi, execute:
 * This will listen on TCP port 8011 for the I/Q signal.
 * The center frequency of the transmitter will be 28400 kHz.
 
+## NFM modulator example in GNU Radio
+
 On the PC, open GNU Radio Companion, and load the flow graph in this repo at `gnuradio/nfm-rpitx`.
 
 ![NFM in GNU Radio](/images/grc-nfm.png?raw=true)