title: How can I update the pulse generator block
body: <p>I have a question, 
  I want to use "Pulse Generator" block to generate square wave form. Then I want to change the phase of the square wave externally. As you know, the phase delay in this block can be adjusted internally. 
  Please let me know how I can update this block in order to connect an input signal which sets the phase of the output signal?</p>
  
  <p>Thanks
  Foad</p>