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What are static hazards?
A static hazard is the situation where, when one input variable changes, the output changes momentarily before stabilizing to the correct value. Static-0 Hazard: the output is currently 0 and after the inputs change, the output momentarily changes to 1,0 before settling on 0.
What causes static hazard?
A static hazard occurs when a single input variable change should cause no change in the output of a combinational logic circuit, but a short glitch of the incorrect logic level occurs. If both inputs change “at the same time”, the output should remain 0.
What are static-0 and static-1 hazards explain the removal of hazards using hazard covers in K-map?
Removal of static-1 hazard: The reason is that the static-1 hazards are based on how we group 1’s (or 0’s for static-0 hazard) for a given set of 1’s in K-map. Thus it does not make any difference in number of 1’s in K-map. The circuit would look like as shown below with the change made for removal of static-1 hazard.
How do you get rid of static one hazard?
Static hazard occur in combinational circuits and can be eliminated by using redundant gates….Difference between Static-1 and Static-0 hazard:
| STATIC-1 HAZARD | STATIC-0 HAZARD |
|---|---|
| SOP is used for removing static-1 hazard. | POS is used for removing static-0 hazard. |
What hazards should you be aware of?
When making a left turn you need to be aware of potential hazards that you cannot see. You also need to be especially aware of pedestrians in the road as they will be more likely to cross at junctions. They have right of way when crossing and are also harder to see than other road users.
Which is an example of a static 0 hazard?
A static 0 hazard may occur in a two level product of sums (POS)implementation. Consider an OR-AND POS implementation with the following characteristics: For the current input conditions only one OR gate has a logic ‘0’ output. This causes the output of the AND to be ‘0’.
When does a digital circuit have a static hazard?
Static-0 Hazard: If the output is currently at logic state 0 and after the input changes its state, the output momentarily changes to 1 before settling on 0, then it is a Static-0 hazard. Lets consider static-1 hazard first. To detect a static-1 hazard for a digital circuit following steps are used:
When is a gate is a static hazard?
This is called a static 1 hazard if this simultaneous change in R and S is caused by a single input variable change. Similarly, for an AND gate with inputs U and V, if U=1 and V=0, the output will be 0. If both inputs change “at the same time”, the output should remain 0.
Can a glitch cause a static 1 Hazard?
If all other sums are ‘1’, then the output should stay ‘1’, but since they are all ANDed with (A’+A), its momentary zero would cause an output glitch which would be a static 1 hazard. Prevention of Static 1 Hazards: