Digital Signal Processing Reference
In-Depth Information
FSM
3
A
2
E
C
m
ctrl
o
1
i
1
i
1
[
] =
t
i
1
[
] =
f
0
0
2
1
o
2
i
2
B
D
m
t
m
f
m
t
m
f
m
ctrl
0
1
1
0
0
o
1
o
1
i
1
i
1
i
1
o
1
1
0
0
1
1
i
2
o
2
i
2
o
2
i
2
o
2
Fig. 5
D
,anda
core functional
Example of a dataflow graph containing four
SDF
actors
A
,
B
,
C
,
2
1
A
i
1
m
ctrl
13
13
2
1
2
1
B
i
2
m
t
C
B
i
2
m
f
D
o
1
o
2
Fig. 6
Example of the static dataflow graphs which can be combined from the three modes which
are present in
core functional dataflow
actor
E
with the four
SDF
actors
A
,
B
,
C
,
D
states. (ii) The
FSM
actor is embedded in the
HDF
domain, and the
FSM
is only
allowed to perform state transitions if a full iteration of the graph has been executed.
(iii) The
FSM
actor is embedded in the
DDF
domain, and the
FSM
performs a state
transition after each firing of the actor. The
core functional dataflow
domain behaves
like
FSM
actors embedded in the
DDF
domain in
*charts
, that is after each firing
of a
core functional dataflow
actor, the mode of the actor may change potentially
modifying the consumption and production rates on the ports.
the static information present in the
core functional dataflow
domain to improve
scheduler generation compared to a simple
round robin scheduler
. The idea is based
on finding sets of modes, where each mode in the set belongs to a distinct
CFDF
actor. The set of modes is constraint to correspond to a consistent
SDF
graph. A
consistent
SDF
graph is a graph which has a non-trivial solution for its balance
equations. Hence,
γ
a
>
0
,∀
actors a. A detailed explanation of consistency can be
The
SDF
actors in Fig.
5
are simply considered
CFDF
actors with exactly one
