Fixed-Point Blockset    

Backward Integration

The FixPt Integrator: Backward realization is a masked subsystem that performs discrete-time integration using the Backward Euler method. The Backward Euler method is also known as the Backward Rectangular method or right-hand approximation. For this method, integration is approximated by the z-domain transfer function

where Ts is the sampling period. The realization is shown below.

As shown in the figure, the transfer function yields the difference equation

where k is the current time step, k - 1 is the previous time step, y(k) is the current output, y(k - 1) is the output from the previous time step, and u(k) is the current input.

Parameters and Dialog Box

The parameters and dialog box for the backward integrator realization are the same as those for the trapezoidal integrator realization, and are given in Parameters and Dialog Box.

Model Design Review

The model design issues are the same as those for the trapezoidal integrator as described in Model Design Review.


 Integrator Realizations Forward Integration