The diagram is trying to show that the convolution function is the same as a digital filter but in a digital filter type structure you have the input being multiplied by a series of filter weights and summed,and the filter is in fact performing convolution,which is just a descreet form of integration.In the convolution coded output its like running the digital filter in reverse.
if you look here this is a good example of someone working though a design in software http://home.netcom.com/~chip.f/v...orial.html
http://en.wikipedia.org/wiki/Convolutional_code here shows in image one the convolutional coder with a shift register with output filter weights m1,m0,m-1 and the input being scaled by thease weights and summed.In fact it done give you the discrete impulse function of the convolutional encoder which if you know your z transforms you can then do a inverse transform to get the time domain version of the output.