rand_bit_stream instance in cadence
I am designing a transimpedance amplifier in Cadence. i am trying to measure the output waveform with eyediagram function.
to do this i heard about rand_bit_stream instance and stimulate the circuit with it. the question is how can i produce 2^31 -1 prbs for 10Gb/s data with this instance. i searched in forum and everywhere, but besides little talks about this instance, nothing is told about how to fill the functions.
so what to write in seed section and tperiod section, tfall,trise and tdel sections to produce 2^31-1 prbs for 10Gb/s
thanks
The seed must be a prime number and it should be big enough. I forgot the algorithm in ADS, but you can search the help in ADS to get the reference to understand the question. Actually, the random in ADS is repeat, but the period should be very long so that in your test period it seems to be random.
thank you tony
do you mean Cadence(spectre) when you say ADS? cause i have to use Cadence.
I can use ran_bit_stream can measure eye diagram. as far as i experienced (because counldnt find anywhere) by making lots of simulations, tperiod must be inverse of the data rate. i gave lots of seed types and did not get logical difference between small number seed and huge number seed
the problem of this forums is that mostly people talk about what they hear and see. when you ask something, somebody says "there is thing...... or in thing you can find..." but nothing useful. the person who asks knows where things should be and where to look for, for sure. what people say is that 99 percent of people know even if the question is very specific and deep.
for example i saw in this forum sb asked "how can i make an S-parameter simulation of current mode circuit(which must be deeply investigated)" and reply is: connect a port from analoglib to inputs and outputs. really? is that all? this method is clasic and for voltage mode circuits. question is about current mode circuits and some mechanism must be solved. so you got no answers except having answer of so basic of s-parameter simulation
I believe you are best at your profession Mr Tony. But i will be so appriciated if you help me out on my specific question which was "how can i produce 2^31-1 prbs using rand_bit_stream instance in Cadence" or "how can i produce 2^31-1 prbs with anything in Cadence"
thanks
About 11 years ago, I worked for Agilent to program some 3GPP ADS modules. But now I actually forgot the methods and the algorithms. Because now I am focused on RF and microwave hardware circuits and don't program for about ten years. And your 2^31-1 is not bigger than 3GPP data streams. Some my pre-colleague used random bit stream for several weeks and don't repeat. So try to find ADS tech support or manuals.
There is no tool which name is Cadence.
Use correct terminologies.
This is also true for him.
https://www.edaboard.com/thread203624.html
What on earth do you mean by rand_bit_stream ?
Describe in detail and correctly.
I assume you mean "ahdlLib/rand_bit_stream" provided in Cadence DFII.
You can use this "ahdlLib/rand_bit_stream" in any vendor's simulator such as Agilent ADSsim, Synopsys HSPICE, Mentor Eldo, Cadence Spectre, etc.
Simply this is because an usage is very easy since it is written by Verilog-A.
So no one except for you raise such very easy question.
Surely see Verilog-A code.
Also see "The Srandom Function" in Mathematical Functions and Operators - ADS 2009 -*Agilent EEsof Documentation Center
The Srandom() function returns a new 32-bit random number each time it is called. The return type is a signed integer.
Of course, you can create Pseudo Noise Generator such as PN9, PN15, etc. based on "Generation Polynomial" without using Srandom().
[Example]Wrong.
Seed can be any integer value generally except for 0.
As far as impedance value of ports can never affect operating points seriously, it is right.
As far as linear operation of circuits, any of S, Y, Z parameters are intrinsic characteristics of circuits.
And they can be calculated from others.
Very Wrong.
S-parameters can be never defined for both voltage mode and current mode.
Can you understand concept of S-parameter correctly ?
S-parameters are defined for power, neither voltage nor current.
Surely learn a theory of S-parameter before posting questions.
The Designer's Guide Community Forum - s-parameter calculation using ac analysis
Scattering parameters - Wikipedia, the free encyclopedia
pancho or whatever,
Your attitudes correct me about what i have written above. Because actually you dont know anything RF and electronics you manipulate the things instead of answering my question. it is so funny you are stuck on the words such as "cadence" "rand_bit_Stream".You have written lots of ridiculus things above nothing is related to the elctronics and RF. that shows you know nothing. rather you manipulate the topic and entertain yourself. you dare to do it here because nobody sees you. you hide yourself behind the computer.
it is the same for the guys who are so ugly, dont have enough self-confidence even to speak a ugly girl in a real world. Instead, you can find these people on facebook, on love-making web sites with the profile photos of Brad Pitt. so let me be a straight. YOU KNOW NOTHİNG. YOU KNOW NOTHİNG BECAUSE YOU PREFER TO MENTION ABOUT THE THINGS WHICH ARE EASY TO UNDERSTAND. AND YOU ARE COVERING YOUR PROFILE PICTURE WITH SOME EXOTIC AND MANIPULATED WORDS.
yes i am right again. in here people writing threads dont help. i explained it at my first shot.
it is not your problem if my question is silly or not, simple or hard. i am situpid or not, well-educated or not. you must give a clear explanation and a hand to me.
let me be a straight again. if i had asked that "what is ohm law", believe me you would answer it with many explanations. because you know as the same as what even high school students know. you wouldnt say that "it is not ohm law. write it correct. it is Ohm's Law", because you dont need to manipulation. ohh there is something you know in the world.
if you think you are ganna write my thread, write about my question.
You have to describe anything correctly.
No, you are wrong.
Simply you are too lacking of very basic knowledge about RF and electronics.
So you can't understand anything.
Surely see my appends.
I wrote very clear answers.
My answers are evaluated as "Helpful" from one people.
However only you can't understand my answer at all.
Again, I wrote very clear answers.
Only you can't understand my answer at all.
I'm always ready to discuss about RF and electronics with you.
Come On !
pancho or whatever,
where is my answer i cannot see it. but i see you here. if you want to talk about RF and electronics then answer my question completely and correctly. then we will se how much you know. but as i see you dont have any ethic rules. you are still here not answering my question. your post must have only been about my question. are you a MONKEY !
it is also so funny that, people like you dont answer any thread, dont help people, lets say if they try, they only write few sentences or few words and mostly these words are not related to the what people ask, writing here lots of things. instead writing that NOVEL OF PANCHO OR WHATEVER, you could have helped me (assuming you know something, in reality you dont. please drop your Brad Pitt picture. put your original picture and let all see how much you are ugly and have lack-of self-confidince) with only 10% of what you have written so far.
if somebıdy asks a question, that does not mean taht he dont know anything. instead, if sb asks a question that means he has enough self-confidince to show-up. dont forget nobody knows everything. guys like you have lack of self-confidince (also lack of understanding, not lack of knowledge because you are knowledgeless) besides not answering topics and shitting even in them, they even cannot ask a question, cannot say "hımmm i dont know that".
so you are Brad Pitt covered boy. if you want to talk about RF with me first you have to correctly, perfectly reply my question
do you have a problem? did not i say to you dont write anything rather than writing about my question and RF !
as for the knowing verilogA or whatever, even if i am professional in RF do i have to know verilogA? if i knew how to do it, why would i ask it here (not the people like you hiding themseves). believe me pancho or whatever, there are many many simple and basic questions being asked here. are all people ask these questions stupid? No but you are stupid. you dont understand the logic that if iam asking a question here, that means i dont know about it. and if i dont know about verilogA, that doesnot mean idont know about RF. if i know about RF, that doesnt mean that i also have to know verilogA
your brain works somewhat different. you still dont get the point (may be you are a disable).read my posts correctly and try to understand. if not then read again until your strange mind comes to point. if it does not work then GO AWAY. YOU DONT EVEN DESERVE TO TALK ABOUT EVEN KIRSHOFF LAWS. be a man. not a girl.
---------- Post added at 22:37 ---------- Previous post was at 22:32 ----------
sorry it must have been Electronics. not electronics. i should correct it because you are ganna write 1 kilos of words about
"first of all it is Electronics not electronics. there is not thing like electronics. but Electronics is a branch of Science" like you said previously "There is no tool which name is Cadence." :))) in addition all specifications you have, you are also funny.
first know about, ports, voltage mode, current mode. then dare to talk about RF. i dont need to know s-parameters but you need to know basic knoledge of electronics. this will help you
Electrical network - Wikipedia, the free encyclopedia
and this one
https://www.edaboard.com/thread88027.html
you first step up the stairs even if your brain is ....but if you try, even if it takes centuries, you will succeed.
check these web sites and learn something. then read about what i have written at my second post to Mr Tonny. about s-parameter simulation, not simple s-parameter basics.
after you try a lot and enough, a candle will light in your mind. hımmmm ok a port is a voltage source !
or else you may say "what is a voltage source, voltage mode"