Re: [myhdl-list] Incorrect conclusions in TSConIT paper

[Norbo <Nor...@gm...>]

Am 29.06.2012, 23:16 Uhr, schrieb Christopher Felton  
<chr...@gm...>:

> <snip>
>>
>> My version with the initial values would look like this:
>>
>>     def firfilt(sig_in, sig_out, coef, clk):
>>         bufferVal = [Signal(intbv(0, min=sig_in.min, max=sig_in.max))  
>> for ii
>> in range(len(coef))]
>>         coefs = [Signal(intbv(ii, min=min(coef), max=max(coef)+1)) for  
>> ii in
>> coef]
>>         mshift = len(sig_in)-1
>>         @always(clk.posedge)
>>         def hdl_sop():
>> 	  sop = 0
>> 	  # Note this adds an extra delay! (Group delay N/2+2)
>> 	  bufferVal[0].next=sig_in
>> 	  for ii in range(len(coef)-1):
>> 	      bufferVal[ii+1].next = bufferVal[ii]
>> 	      sop = sop + (bufferVal[ii] * coefs[ii])
>> 	  sig_out.next = (sop >> mshift)
>>
>>         return hdl_sop
>>
>> but there is still the shift error.
>>
>>
>> greetings
>> Norbo
>>
>>
>
> I don't think the above would work because the loop doesn't use
> bufferVal[len(coef)-1) and coef[len(coef)-1].

thanks, of course it should look like this:

      def firfilt(sig_in, sig_out, coef, clk):
          bufferVal = [Signal(intbv(0, min=sig_in.min, max=sig_in.max))   
for ii in range(len(coef))]
          coefs = [Signal(intbv(ii, min=min(coef), max=max(coef)+1)) for   
ii in coef]
          mshift = len(sig_in)-1
          @always(clk.posedge)
          def hdl_sop():
            sop = (bufferVal[0] * coefs[0])
            # Note this adds an extra delay! (Group delay N/2+2)
            bufferVal[0].next=sig_in
	
            for ii in range(len(coef)-1):
               bufferVal[ii+1].next = bufferVal[ii]
               sop = sop + (bufferVal[ii+1] * coefs[ii+1])
            sig_out.next = (sop >> mshift)

          return hdl_sop

greetings
Norbo