The document discusses delay models in VHDL, specifically inertial and transport delays. Inertial delay helps filter out noise in switching circuits, while transport delay models pure propagation without filtering. The conclusion emphasizes the usefulness of both models in modeling signal delays and propagation.

1. MEWAR UNIVERSITY
Presented by: Presented to:
Kamal Jeet Mr Sayed arif ali
B.tech (ECE) 3rd yr Dept. of (ECE)

2. CONTENTS
Introduction
Inertial delay with examples
Transport delay
Conclusion

3. DELAY MODELS IN VHDL
The delay models are
 Inertial delay
 Transport delay

4. Inertial delay
Models the delays found in switching circuits.
It is used for removing noises
The value appears at the output after the
specified inertial delay.

5. Inertial Delay
The format is;
T<= reject TIME_2 inertial VALUE after TIME_1;
This is the default delay model.

7.  The following assignments are equivalent:
T<= VALUE after TIME_1; --(default inertial
delay)
 T<= inertial VALUE after TIME_1;
Furthermore “ T<= VALUE “ is just a shortcut
for
T<= VALUE after 0 ns
If no pulse rejection limit is specified, the
default PRL is the inertial delay value itself.

8. Transport delay model
 Models the propagation delay.
 Transport delay models signal transfers through wire with pure
propagation delay, thus spikes are not filtered out like inertial
delay.
 Key word transport must be use in a signal assignment statement.

9. CONCLUSION
In short we have seen that inertial delay model
can be used to model delays associated with
switching circuit and for rejecting noise in
particular.
Transport delay model is used for modelling
propagation delay

10. References
 https://web.ewu.edu/groups/technology/Claudio/ee36010/Lectures/delay_models.
pdf
 www.gmvhdl.com/delay
 www.technicalguruji.com
 http://surf-vhdl.com/vhdl-syntax-web-course-surf-vhdl/vhdl-delay-type-modeling/
 https://electronics.stackexchange.com/questions/227919/how-important-is-gate-
delay-when-designing-a-circuit