replace in opening quotations

node179.html

@@ -157,14 +157,14 @@ block of computation outputs the same first <IMG
  ALT="$N$"> samples of the table.
 
 <P>
-In this example, the table ``$0-hann" holds a Hann window function
+In this example, the table "$0-hann" holds a Hann window function
 of length 512, in agreement with the specified block size.  The signal
 to be analyzed appears (from the parent patch) via the <TT>inlet~</TT> object.
 The channel amplitudes (the output of the <TT>rfft~</TT> object) are reduced
 to real-valued magnitudes: the real and imaginary parts are squared separately,
 the two squares are added, and the result passed to the <TT>sqrt~</TT> object.
 Finally the magnitude is written (controlled by a connection not shown in
-the figure) via <TT>tabwrite~</TT> to another table, ``$0-magnitude", for
+the figure) via <TT>tabwrite~</TT> to another table, "$0-magnitude", for
 graphing.
 
 <P>
@@ -234,7 +234,7 @@ A modification is applied, however: each channel is multiplied by a
 (positive real-valued) gain.   The complex-valued amplitude for each channel is
 scaled by separately multiplying the real and imaginary parts by the gain. The
 gain (which depends on the channel) comes from another table, named
-``$0-gain".   The result is a graphical equalization filter; by mousing in the
+"$0-gain".   The result is a graphical equalization filter; by mousing in the
 graphical window for this table, you can design gain-frequency curves.
 
 <P>