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Thesis - Leigh Moody.pdf - Bad Request - Cranfield University

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Appendix I / Utilities / Digital Filters<br />

_ _<br />

22.8.13 Digital Interface 2s Complement Wrap Filter<br />

IF_2CW takes input (XI) and wraps it into the range [XL,XU] emulating a 2s<br />

complement implementation.<br />

y : = IF_2WC<br />

I<br />

22.8-10<br />

( X , X , X )<br />

[ XL<br />

, XU<br />

] ⇒ y : XI<br />

X ∈<br />

=<br />

y = X → X − X + X until X ≤ X<br />

I<br />

I<br />

I<br />

I<br />

U<br />

y = X → X + X − X until X ≥ X<br />

U<br />

I<br />

L<br />

L<br />

L<br />

U<br />

I<br />

I<br />

Equation 22.8-67<br />

Equation 22.8-68<br />

L<br />

Equation 22.8-69<br />

Equation 22.8-70<br />

This algorithm wraps inputs into a symmetric range about zero and cannot<br />

be used for unsigned input representations in the range [0,XU].<br />

22.8.14 Parameter Limiting<br />

R_LIMITER limits the real valued input (XI) to the range [XL,XU].<br />

( X , X , X ) ≡ ( X , X , X )<br />

y : = R_LIMITER<br />

ϕ<br />

I<br />

I<br />

L<br />

U<br />

RL<br />

] − ∞ , X L ] ⇒ y : X L<br />

X ∈<br />

=<br />

I<br />

] XL<br />

, XU<br />

[ ⇒ y : XI<br />

X ∈<br />

=<br />

I<br />

[ XU<br />

, ∞ [ ⇒ y : XU<br />

X ∈<br />

=<br />

I<br />

U<br />

LL<br />

UL<br />

Equation 22.8-71<br />

Equation 22.8-72<br />

Equation 22.8-73<br />

Equation 22.8-74<br />

I_LIMITER limits the integer input (XI) to the range [XL(1)XU] using the<br />

same logic.<br />

( X , X , X ) ≡ ( X , X , X )<br />

y : = I_LIMITER<br />

ϕ<br />

I<br />

L<br />

U<br />

IL<br />

I<br />

LL<br />

UL<br />

Equation 22.8-75

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