Update README for new interpolating modulator block.

README

@@ -28,7 +28,7 @@ transmitter, based on the EN 300 421 V1.1.2 Framing structure,
 channel coding and modulation for 11/12 GHz satellite services
 standard:
 
-    http://www.etsi.org/deliver/etsi_en/300400_300499/300421/01.01.02_60/en_300421v010102p.pdf
+http://www.etsi.org/deliver/etsi_en/300400_300499/300421/01.01.02_60/en_300421v010102p.pdf
 
 The randomizer, Reed Solomon, and puncturing blocks are from
 gr-dvb (https://github.com/EdmundTse/gr-dvb) and converted to
@@ -50,3 +50,10 @@ Build instructions:
 
 Contributions are welcome!
 
+Update (6/18/2014):
+
+A new DVB-S modulator block has been added that implements
+zero-stuffing 2X interpolation. This allows the use of an
+FFT-based root-raised-cosine filter instead of the more
+computationally intense interpolating FIR filter.
+