Re: feedback opcodes

From: Robin Davies (rerdavies@msn.com)
Date: Fri Apr 21 2000 - 16:16:00 EDT


>Who can tell me, which opcodes do contain feedbacks loops ?
>"luckily, only two cases" on the 3D webpage doesn´t say which ;-)
>
>best
>
>mareK
: Giorgio Zoia\

: - fracdelay
: - tableread/tablewrite

Array referecnces also allow for feedback, well as a number of interesting
inter-rate communications techniques. Hence, the following constructs also
provide for feedback:

asig Echo1(asig x, ivar feedback)
{
    avar xdelay[1];
    index = 1;
    xdelay[index] = x+ feedback*xdelay[index];
    return (xdelay[index]);
}

Since the standard says that array references expressions (lvalue and
ravalue) take the higher rate of their array variable and array index, my
reading of the standard is that the following kinds of things are legal too:

    ksig kIndex;
    asig aIndex;
    ivar iArray;

   iArray[aIndex] = aSomeSignal; // Write at A-rate
   kSomeVal = iArray[kIndex]; // Read at K-Rate.

Any opinions on the legality of this?



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