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ramesh441
Joined: 11 Feb 2009
Posts: 56
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 29 Oct 2009 5:52 Help me on finding delay on cadence Spectre |
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Hello friends
I had made a ciruit having 16 inputs containing DC supply and having one output getting dc constant voltage as a result.
now I want to find the delay betwen the 16th input and output
Can I know how could I do in cadence Spectre
Thanking you,
RamesH
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ieropsaltic
Joined: 25 Sep 2006
Posts: 205
Helped: 44
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29 Oct 2009 7:26 Re: Help me on finding delay on cadence Spectre |
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Hello,
From the ADE Design environment -> tools -> calculator.
From the functions -> choose "cross"
at "signal" -> write the name of signal (VT("/net010") for e.g where net010 is the net name)
at "Threshold Value" -> write the crossing (voltage) value where delay is required (usually Vdd/2 in digital circuits).
at "Edge Number" -> if the point is crossed more than once, define which one should be considered
at "Edge type" -> choose either rising or falling depending on crossing direction
Repeat steps for both signal then subtract and you'll get the delay.
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ramesh441
Joined: 11 Feb 2009
Posts: 56
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29 Oct 2009 7:41 Re: Help me on finding delay on cadence Spectre |
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Sir,
My question is, for a dc voltage which wont vary.
My input is 1.2 volts constant dc. and output is 0.9 voltage a constant dc.
How could I get the delay of it?? i.e how much time is the circuit taking from my 16th input to o/p
Thanking you,
RamesH
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srpatel9
Joined: 14 Mar 2009
Posts: 28
Location: USA
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29 Oct 2009 10:38 Re: Help me on finding delay on cadence Spectre |
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Can you explain a bit more about your circuit- as in beahviour?
Is there any clock in your circuit.
What are there DC input? Step inputs? If so how and when do they get triggered?
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ramesh441
Joined: 11 Feb 2009
Posts: 56
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29 Oct 2009 12:56 Re: Help me on finding delay on cadence Spectre |
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My input a dc 1.2 V constant and its not varing
How could I measure delay as there is no variation in signal w.r.t time
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29 Oct 2009 12:56 Ads |
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ieropsaltic
Joined: 25 Sep 2006
Posts: 205
Helped: 44
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30 Oct 2009 11:06 Re: Help me on finding delay on cadence Spectre |
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| I think for simualtion purposes, your input should not be a DC source, rather a Vpulse that would step from 0 to the required supply value and get held to this value. In this case, you can accurately estimate the delay between the time of applying the DC source to the time the output would respond. If you use a DC source at the input, cadence (or spectre) will (usually) start calculating the transient initial state from the dc solution, which is usually the circuit's final steady state and you'd never see the delay. So, by using Vpulse you'll force a different initial state and can see the delay.
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