1000 Threads found on edaboard.com: Linear Feedback Shift Register
lfsr linear feedback shift register!! used in BIST.
can anyone explain working of this!
if possible upload some material !! i dont hav anything
ASIC Design Methodologies and Tools (Digital) :: 05-21-2007 11:50 :: shiv_emf :: Replies: 1 :: Views: 2363
Can anyone help me understand that how does a LFSR (linear feedback shift register) implement division required for CRC (cyclic redundancy check) ?
ASIC Design Methodologies and Tools (Digital) :: 07-01-2013 00:43 :: e-bedlam :: Replies: 1 :: Views: 274
you can also look at :
linear feedback shift register &
cellular automata shift register
ASIC Design Methodologies and Tools (Digital) :: 08-08-2007 01:42 :: sree205 :: Replies: 4 :: Views: 736
Hello everybody ...
this my first thread in the forums and i wonder if you can help me with the VHDL code that i'm looking for ..
which is about 31 bits linear feedback shift Resistor(LFSR) ..
and also the method for synchrization of this machine on the Xilinx FPGA Board...
Thanx in Advance guys...
PLD, SPLD, GAL, CPLD, FPGA Design :: 04-26-2008 12:42 :: Sultan1551 :: Replies: 1 :: Views: 6101
2. How we choose cherterstic polynomial for lfsr?
The characteristic plynomial is the LFSR connection which will give the maximum number of random values before it starts to repeat the values. Each LFSR will have a characteristic polynomial, which is pre-determined. There are equation to find that, which I don't remember just
ASIC Design Methodologies and Tools (Digital) :: 03-24-2008 05:20 :: vlsi_eda_guy :: Replies: 7 :: Views: 1998
I'm interesting in generating some random numbers for one of my projects.
I have stumbled across the following code snippet:
It appears to use feedback shift registers to generate a pseudo random sequence.
Does anyone have any thoughts / comments / better examples?
Many thanks in adva
Microcontrollers :: 01-08-2010 09:04 :: the_merovingian :: Replies: 2 :: Views: 1386
in addition to the stuff from bartart:
xapp052 (especially this one), xapp217, xapp220 from Xilinx documentation.
These are LFSR (linear feedback shift register) designs that produce pseudo (careful!)-random sequences. This means that eventually they get repeated. But if you have e.g. a 32-bit LFSR producing a maximal (...)
PLD, SPLD, GAL, CPLD, FPGA Design :: 06-25-2004 10:20 :: the_penetrator :: Replies: 2 :: Views: 2341
Search for linear feedback shift register (or LFSR)on google. This structure is basically a circular shift register with XOR gates between some of the stages, it produces a pseudo-random sequence when clocked...
ASIC Design Methodologies and Tools (Digital) :: 01-28-2005 20:28 :: eternal_nan :: Replies: 17 :: Views: 1759
I need Gaussian and uniform noise. I can’t use a function because I need to put it in a FPGA so I need to make it out of basic math (+, -, * etc..). I’ve used the MATLAB noise generators and they work great.
You can use LFSR (linear feedback shift register) to produce noise in certain band. For
PLD, SPLD, GAL, CPLD, FPGA Design :: 02-23-2005 02:00 :: Black Jack :: Replies: 5 :: Views: 1797
I see this problem like this:
every tap (in your case x**14 and x**15) in LFSR (linear-feedback shift register) of your polynomial adds one additional error in the receiver. So the sum of all errors is three since original error plus two tap errors equals three.
I'm not sure about your code since I don't understand the (...)
Digital Signal Processing :: 07-15-2005 10:02 :: rfmw :: Replies: 6 :: Views: 3704
My BS project was in LDPC. in some case of LDPC code, encoding is very easy. in this case LDPC code generate by just LFSR(linear feedback shift register) like cyclic code. In this case some kind of Geometry code (EG and PG) are LDPC.
But decoding ?
LDPC codes have 3 method for decoding.
1- using Majority Logic (...)
Digital Signal Processing :: 07-25-2006 04:07 :: m_llaa :: Replies: 9 :: Views: 5123
A linear feedback shift register (LFSR) is an easy way to generate a pseudo-random bit stream in hardware by using a shift register and XNOR gate. Here are a couple of Xilinx app notes, and HDL examples:
Digital communication :: 12-19-2005 03:30 :: echo47 :: Replies: 3 :: Views: 2532
random pattern?? -> use LFSR (linear feedback shift register)
ASIC Design Methodologies and Tools (Digital) :: 02-23-2006 05:26 :: eda_wiz :: Replies: 1 :: Views: 876
LFSR is "linear feedback shift register"
It is used to make pseudo random generator
I'm afraid that this circuit is not working properly.
all D output digital number is 0, it does not generate some codes
in additional to, in my thought, It does not generate random codes, just shift codes
Analog Circuit Design :: 04-04-2006 20:57 :: 020170 :: Replies: 5 :: Views: 7787
What version of Modesim are you using? The default resolution Modelsim uses is 1 picosecond, so any simulation of a minute requires an enormous amount of clock cycles. This resolution can be changed. Also, this will syntesize using a 25 bit counter, which can be hard to route with a 25MHz clock (depends on the device you are using). It may be b
PLD, SPLD, GAL, CPLD, FPGA Design :: 04-21-2006 06:48 :: MWind :: Replies: 6 :: Views: 1071
I am designing "Data Randomizer" in verilog in which i am using a polynomial.
G : x16 + x13 + x12 + x11 + x7 + x6 + x3 + x + 1
My Query is : On what basis we choose a polynomial equation and if we implement this equation using LFSR(linear feedback shift register) where to place tabs for output ?
ASIC Design Methodologies and Tools (Digital) :: 01-05-2007 01:38 :: kunal1514 :: Replies: 0 :: Views: 457
u can use LFSR (linear feedback shift register)
Digital Signal Processing :: 06-10-2007 01:25 :: m_llaa :: Replies: 4 :: Views: 3795
you can try LFSR, the diagram and its C code can be found in
ASIC Design Methodologies and Tools (Digital) :: 11-16-2008 12:51 :: linkfox :: Replies: 2 :: Views: 10712
I have to write the scrambler code in verilog. The scrambler is LFSR(linear feedback shift register) based.
The 23-bit polynomial for the LFSR is G(X) = X23 + X21 + X16 + X8 + X5 + X2 + 1
The main problem I am facing is finding the value of LFSR after 8 serial clocks (1 bit advanced in each clock).
There are 2 (...)
ASIC Design Methodologies and Tools (Digital) :: 04-11-2009 07:10 :: aman_geek :: Replies: 6 :: Views: 6699
Signal source is a (pseudo-)random sequence generator.
Oscilloscope must have external trigger input, use sequence generator clock as trigger signal.
To measure, hook up oscilloscope to end of transmission media (receiver side).
To implement a sequence generator in HW, google 'linear feedback shift register" for (...)
PCB Routing Schematic Layout software and Simulation :: 08-08-2009 07:17 :: alenze :: Replies: 1 :: Views: 2671
Please help guys.. i need to perform the run and correlation property on a stream of bits that has been pseudorandomly generated.
I have used the following piece of code: e.g x= randn(10,1)>0.5 to generate random bits of 0's and 1's. Is this the correct way of doing it or do i need to pass through the linear feedback shift (...)
Digital communication :: 12-10-2009 10:33 :: dammadmin :: Replies: 0 :: Views: 820
I am not sure if I am asking the right question but what is LFSR and MISR? Are they both used around MBIST engine or inside MBIST engine and how?
lfsr is linear feedback shift register.this is for generating random patterns.There are different types of LFSR. In testing of
ASIC Design Methodologies and Tools (Digital) :: 08-30-2013 13:49 :: jincyjohnson :: Replies: 2 :: Views: 1746
i want vhdl code for signature analyzer for built in self test circuit... i can use 8 bit linear feedback shift register(LFSR) na?i am trying using 8 bit LFSR
PLD, SPLD, GAL, CPLD, FPGA Design :: 02-15-2010 01:16 :: divsec :: Replies: 0 :: Views: 923
Ouput of LFSR Properties that confuse me:
1. "Ones and zeroes occur in 'runs'. The output stream 0110100, for example consists of five runs of lengths 1,2,1,1,2, in order. In one period of a maximal LFSR, 2n − 1 runs occur (for example, a six bit LFSR will have 32 runs). Exactly 1/2 of these runs will be one bit long, 1/4 will be two bit
Digital Signal Processing :: 08-27-2010 11:33 :: jasonkee111 :: Replies: 0 :: Views: 602
I have code for linear feedback shift register. It is not a random number generator in the strict sense. But must be useful in some cases.Download it from opencore.org:
LFSR-Random number generator :: Overview :: OpenCores
PLD, SPLD, GAL, CPLD, FPGA Design :: 10-20-2010 09:57 :: vipinlal :: Replies: 3 :: Views: 2264
For maximum length LFSR polynominals, see linear feedback shift register - Wikipedia, the free encyclopedia
If you want other than maximum length PN codes, you should tell a specification first.
Digital communication :: 11-14-2010 09:05 :: FvM :: Replies: 1 :: Views: 844
sir, i need a bist architecture for prbs generator using vhdl. i searched in website but ther's no file. so wil u plz help me :-?
what do you mean with "bist architecture for prbs generator"?
for a prbs implementation you can also google for lfsr
here some links for a prbs generator with vhdl
Electronic Elementary Questions :: 01-20-2011 07:29 :: qieda :: Replies: 1 :: Views: 2255
linear feedback shift register - Wikipedia, the free encyclopedia
ASIC Design Methodologies and Tools (Digital) :: 01-23-2011 23:09 :: lostinxlation :: Replies: 6 :: Views: 1257
Implement linear feedback shift register in C code instead of a typical gate level netlist.
Microcontrollers :: 02-27-2011 22:53 :: lostinxlation :: Replies: 3 :: Views: 810
Usually, a feedback shift register is the answer linear feedback shift register - Wikipedia, the free encyclopedia
Hobby Circuits and Small Projects Problems :: 03-03-2011 14:46 :: FvM :: Replies: 4 :: Views: 1709
can anyone please send me the study material explaining the concept of linear feedback shift register(LFSR) and how it is applied for built in self test(BIST)
ASIC Design Methodologies and Tools (Digital) :: 04-21-2011 11:17 :: avinashch :: Replies: 7 :: Views: 628
as mentioned above, there is not a single galois field equation. not a single one per size of galois field. wikipedia has some. you can extract them from the taps given LFSR Reference -- M-Sequence, linear feedback shift register, Feedbac
ASIC Design Methodologies and Tools (Digital) :: 07-08-2011 21:45 :: permute :: Replies: 3 :: Views: 668
In SAR ADC, clock for both comparator and the controller should be same if you are going to design synchronous SAR. Each clock has positive level and negative level. Generally at positive edge controller plugged the capacitor and positive lever time is used to settle the voltage. for all this time comparator is in reset mode, so any hangup problem
Electronic Elementary Questions :: 09-30-2011 12:48 :: rongo024 :: Replies: 2 :: Views: 701
The protocol specification usually defines CRC in hex or polynomial notation. For example, CRC5 used in USB 2.0 protocol is represented as 0×5 in hex notation or as G(x)=x5+x2+1 in the polynomial notation. This CRC is typically implemented in hardware as a linear feedback shift register (LFSR) with a serial data input
ASIC Design Methodologies and Tools (Digital) :: 11-30-2011 12:02 :: yura717 :: Replies: 3 :: Views: 523
if you r talking abt PRBS(Pseudo Random Binary Sequence) generator, u should specify how many bits or the length . If u want n- bit PRBS generator ,then it can give u 2^n-1 binary sequences.
For PRBS FPGAsRus PRBS which are usually implemented using an LFSR(linear feedback shift register) i.e shift regi
ASIC Design Methodologies and Tools (Digital) :: 12-13-2011 07:34 :: antaryami.mt.er09 :: Replies: 4 :: Views: 2287
Is it the same as the white noise which means the power is equally divided in the whole frequency range?
If so, how does it come? Any reference is preferred.
Now I've built a pseudo-random sequence using linear feedback shift register(LFSR), and I'd like to check its power spectral, is it possible to make it out using (...)
Analog Circuit Design :: 12-17-2011 06:07 :: bsaqycx :: Replies: 0 :: Views: 268
I am hoping that this is the right forum to ask this question. I am trying to synthesize the code for a linear feedback shift register. The code is below
input op; //defines the operation
PLD, SPLD, GAL, CPLD, FPGA Design :: 06-28-2013 15:43 :: atifhashmi :: Replies: 2 :: Views: 457
THe Pseudo Random-Bit Generator Source or PRBS is defined in CHapter 5 of the manual
There are many variables based on linear feedback shift register (LFSR)
Certain comibinations of taps and length of shift register are chosen for "maximal length sequence" (MLS) YOu may only be concerned (...)
Analog Circuit Design :: 06-19-2014 14:59 :: SunnySkyguy :: Replies: 4 :: Views: 378
Hey, guys, though shift register design seems belong to digital design, I still would like to post my message here, since my case is a little bit different.
I have two complementary clocks, voltage swing 0-3.3V, and internal logic is using -6V ~ 6V or even higher, PMOS and NMOS threshold voltages are about 2.5V(kind of strang process :cry:).
Analog IC Design and Layout :: 05-11-2006 14:08 :: bageduke :: Replies: 5 :: Views: 1494
Hello, I was reading the LFSR from a book where it is saying that n-bit shift register counters have far less than the maximum of 2^n normal states while an n bit linear shift register counter can have (2^n)-1 states which is almost the maximum number of states.
I didn't get it. Suppose we have a 3 bit (...)
ASIC Design Methodologies and Tools (Digital) :: 09-28-2011 23:23 :: crazyeng0 :: Replies: 0 :: Views: 328
hello there i have written the following in VHDL a code for a rotating registers should start with 1000 then rotate then 1 with each cycle 0100 0010 0001
the problem is i am not getting any output on the output bus
can anyone help?
entity writeren is
generic (M: integer:=4);
clk, reset: in std_logic;
wr_en: in std
PLD, SPLD, GAL, CPLD, FPGA Design :: 07-08-2013 06:35 :: ghattasak :: Replies: 7 :: Views: 500
I need a 16 bits shift register. I perfer to implement it in a PLD. please tell me which one is suitable. small pin unmber, low power consumption is under consideration.
PLD, SPLD, GAL, CPLD, FPGA Design :: 06-27-2003 16:24 :: Richard Luo :: Replies: 8 :: Views: 2465
I am looking for an:
"8 bit shift register with separate parallel in/parallel out"
simillar to SN74199 which has gone obsolete.
Any suggestions ?
ASIC Design Methodologies and Tools (Digital) :: 04-29-2004 11:09 :: NTFS :: Replies: 3 :: Views: 1299
Xilinx app note 052, "Efficient shift registers, LFSR Counters, and Long Pseudo-Random Sequence Generators"
Xilinx app note 210, "linear feedback shift registers in Virtex Devices"
Electronic Elementary Questions :: 10-10-2004 08:00 :: echo47 :: Replies: 4 :: Views: 2454
You can use a simple shift register with feedback from two or more points, or taps, in the register chain. The data input to the shift register is generated by XOR-ing or XNOR-ing the tap bits; the remaining bits function as a standard shift register.
ASIC Design Methodologies and Tools (Digital) :: 05-23-2005 04:52 :: svicent :: Replies: 5 :: Views: 3854
try to find this excellent book covering your questions: Solomon W. Golomb, shift register Sequences, Aegean Park Press, California, 1982.
XOR gates give, in the case of binary system, linear addition, which is needed to form a linear-feedback shift registers, (...)
Electronic Elementary Questions :: 08-09-2005 07:22 :: rfmw :: Replies: 3 :: Views: 800
i'm looking for parts with the following specification:
1. 4/8 bit shift register with 3V supply.
2. quad 2 input AND gate with 3V suuply
Analog Circuit Design :: 08-20-2005 15:17 :: BMWE :: Replies: 1 :: Views: 603
if i send some 8-bit serial data to shift register 74ls164 and stop, will the data be latched on output of this serial-to-parallel convertor 74ls164. if no, which ic or technique can i use to do the same.
Microcontrollers :: 11-01-2005 14:25 :: sush :: Replies: 4 :: Views: 2456
linear phase shift means same phase shift for all frequency of the signal which is equal to delay in time domain ie we will get the output after delay
If it is nonlinear means in the frequency domain it will produce different phase shift for different frequencies of same signal which when displayed in time (...)
Electronic Elementary Questions :: 12-20-2005 06:44 :: electronics_kumar :: Replies: 2 :: Views: 2244
Hox to do in order to instantiate shift register SR16RE in vhdl code.
PLD, SPLD, GAL, CPLD, FPGA Design :: 01-09-2006 04:16 :: voho :: Replies: 3 :: Views: 797