User`s guide

Sample Rate Transitions

7-17

Three key points about this diagram:

1 Unit delay output runs in 1 sec task, but only at its rate (2 sec). The output

of the unit delay block feeds the 1 sec task blocks.

2 The unit delay update uses the output of the 2 sec task in its update of its

internal state.

3 The unit delay update uses the state of the unit delay in the 1 sec task.

The output portion of a Unit Delay block is executed at the sample rate of the

slower block, but with the priority of the faster block. Since a Unit Delay block

drives the faster block and has effectively the same priority, it is executed

before the faster block. This solves the first problem.

The second problem is alleviated because the Unit Delay block executes at a

slower rate and its output does not change during the computation of the faster

block it is driving.

1/z

Time

T=1s

t2 t3

1Sec

Task

2Sec

output

T=1s

1/z

output

1/z

output

T=1s

T=2s

1/z

update

Task

T=2s

1/z

update