| Author |
Message |
bijoy
Guest
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 Posted:
Fri Dec 02, 2005 9:15 am Post subject:
FPGA : Decimation Filter Implementation |
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Hello
I am trying to reverse engineer the
decimation filter core provided by xilinx core-generator.
My requirements are
1. Input data rate : 8.8 M Hz 2. Decimation ratio : 2 3. Number of taps : 32 4. input and coefficeints width:16 5. symmetric filter Xilinx core generator uses
One multiplier
Two Block ram to store coefficient and input data clock frequency required : 70 MHz
How does they achieve this
I am not able to find out a structure that can expoit both decimation and symmetry of the filter to reduce the multipliers to 1 and clock frequency to 70 MHz.
I want to store the coefficient and input data in block ram so that i can save slice usage.
Can any one suggest any ideas ?
Thanks bijoy |
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Simon Peacock
Guest
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| Posted:
Fri Dec 02, 2005 3:53 pm Post subject:
Re: FPGA : Decimation Filter Implementation |
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For starters.. you shouldn't mention "reverse-engineer" and "Xilinx core
generator" in here.. this is a monitored group by both Altera and Xilinx...
both will not appreciate it.
(not to mention those of us who make our living from the IP business)
Simon
"bijoy" <pbijoy@rediffmail.com> wrote in message
news:ee927da.-1@webx.sUN8CHnE...
| Quote: | Hello
I am trying to reverse engineer the
decimation filter core provided by xilinx core-generator.
My requirements are
1. Input data rate : 8.8 M Hz 2. Decimation ratio : 2 3. Number of taps :
32 4. input and coefficeints width:16 5. symmetric filter Xilinx core |
generator uses
| Quote: |
One multiplier
Two Block ram to store coefficient and input data clock frequency required
: 70 MHz
How does they achieve this
I am not able to find out a structure that can expoit both decimation and
symmetry of the filter to reduce the multipliers to 1 and clock frequency to |
70 MHz.
| Quote: |
I want to store the coefficient and input data in block ram so that i can
save slice usage.
Can any one suggest any ideas ?
Thanks bijoy |
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Symon
Guest
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| Posted:
Sat Dec 03, 2005 1:16 am Post subject:
Re: FPGA : Decimation Filter Implementation |
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Hi Simon,
He could well have a legitimate reason for reverse-engineering the core.
Perhaps he wants to see if anyone is infringing his own patent? Although,
from his post, I guess not. Also, I believe it's lawful to reverse-engineer
something which is protected by trade secrets rather than a patent. That is,
unless you stole the thing you're reverse-engineering.
Still, as you say, best not to advertise it whatever the reasons.
Cheers, Syms.
p...s... I think there's something wrong with your full stop key... In a lot
of your posts it keeps coming out in duplicate or triplicate... ;;;---)))
"Simon Peacock" <simon$actrix.co.nz> wrote in message
news:439019ae$1@news2.actrix.gen.nz...
| Quote: | For starters.. you shouldn't mention "reverse-engineer" and "Xilinx core
generator" in here.. this is a monitored group by both Altera and
Xilinx...
both will not appreciate it.
(not to mention those of us who make our living from the IP business)
Simon |
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Simon Peacock
Guest
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| Posted:
Mon Dec 05, 2005 9:15 am Post subject:
Re: FPGA : Decimation Filter Implementation |
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'...' is a pause as opposed to '.' a stop. Even text to speech recognises
this. I will try to refrain... maybe
But reverse engineering can be done to anything. A copyright message is all
you need to 'stop' it but that isn't usually enough. I myself have been
designing for 20+ years and have purposefully released things as GPL so they
can be public. Other stuff (hardware and software) is most defiantly not
public. I have some rather flash UARTS, Ethernet Interfaces and E1 units.
These add value to both my pay-packet each month and to my companies
standing. They also make sure that each company review, there is a reason
to keep me employed. I've also started studying towards a BE-Tech and
possibly a Masters. So why do I think its not OK to copy? There are
multiple reasons above.
The only time I would recommend breaking a copyright is when the company is
defunct and you need to do an update but even then someone might have walked
away with the copyright/patent.
Simon
"Symon" <symon_brewer@hotmail.com> wrote in message
news:4390a9a6_3@x-privat.org...
| Quote: | Hi Simon,
He could well have a legitimate reason for reverse-engineering the core.
Perhaps he wants to see if anyone is infringing his own patent? Although,
from his post, I guess not. Also, I believe it's lawful to
reverse-engineer
something which is protected by trade secrets rather than a patent. That
is,
unless you stole the thing you're reverse-engineering.
Still, as you say, best not to advertise it whatever the reasons.
Cheers, Syms.
p...s... I think there's something wrong with your full stop key... In a
lot
of your posts it keeps coming out in duplicate or triplicate... ;;;---)))
"Simon Peacock" <simon$actrix.co.nz> wrote in message
news:439019ae$1@news2.actrix.gen.nz...
For starters.. you shouldn't mention "reverse-engineer" and "Xilinx core
generator" in here.. this is a monitored group by both Altera and
Xilinx...
both will not appreciate it.
(not to mention those of us who make our living from the IP business)
Simon
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Symon
Guest
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| Posted:
Tue Dec 06, 2005 1:15 am Post subject:
Re: FPGA : Decimation Filter Implementation |
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"Simon Peacock" <simon$actrix.co.nz> wrote in message
news:4393ddf2@news2.actrix.gen.nz...
| Quote: | '...' is a pause as opposed to '.' a stop. Even text to speech recognises
this. I will try to refrain... maybe
Yeah, sorry, I was just being a smartass. There's an interesting Wikipedia |
article all about the ellipsis. http://en.wikipedia.org/wiki/Ellipsis
| Quote: |
But reverse engineering can be done to anything. A copyright message is
all
you need to 'stop' it but that isn't usually enough. I myself have been
designing for 20+ years and have purposefully released things as GPL so
they
can be public. Other stuff (hardware and software) is most defiantly not
public. I have some rather flash UARTS, Ethernet Interfaces and E1 units.
These add value to both my pay-packet each month and to my companies
standing. They also make sure that each company review, there is a reason
to keep me employed. I've also started studying towards a BE-Tech and
possibly a Masters. So why do I think its not OK to copy? There are
multiple reasons above.
The only time I would recommend breaking a copyright is when the company
is
defunct and you need to do an update but even then someone might have
walked
away with the copyright/patent.
Simon
OK, but if 'reverse engineering' is just finding out how something works, |
then that's fine, yes? For example, books are copyrighted, but you can still
read them. As to what you then do with the knowledge you gain, I guess
that's where the line between good and evil is. If you read a copyrighted
electronics text book, it's ok to use the knowledge you gain to design
electronics, or even to write your own textbook, provided you don't copy
verbatim. If you reverse engineer a FIR filter, it's ok (legally and
morally?) to use the knowledge you've gained to create your own, provided
it's not a direct copy. Maybe! In the US, maybe the DMCA has some
ramifications as to the legality of reverse engineering.
Interesting subject, I guess there's not a black and white answer.
Cheers, Syms. |
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Simon Peacock
Guest
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| Posted:
Tue Dec 06, 2005 9:15 am Post subject:
Re: FPGA : Decimation Filter Implementation |
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Yews and no.. it could be argued that books are by design, designed to be
read. Take a look at the copyright message for most software. "cannot be
disassembled for any purpose" is a very common phrase
"In order to protect them you may not decompile, reverse engineer,
disassemble, or otherwise reduce the Software to a human-perceivable form."
This is from the Xilinx EULA for the development tools. I don't have
core-generator handy, but as you can see, they don't want you to view in any
shape or form their software. Altera might be different but that is because
their tools were built with or include GNU
You can of course copy directly from a book, I think anyone would be hard
pressed to stop someone or even to prove they had exclusive rights to
something found in print, you would only have to find it in a different book
printed before the one in question to automatically invalidate any clams.
Of course, the invention of time travel will make all patents null and void
:-)
Simon
"Symon" <symon_brewer@hotmail.com> wrote in message
news:4394ba9d$1_3@x-privat.org...
| Quote: | "Simon Peacock" <simon$actrix.co.nz> wrote in message
news:4393ddf2@news2.actrix.gen.nz...
'...' is a pause as opposed to '.' a stop. Even text to speech
recognises
this. I will try to refrain... maybe
Yeah, sorry, I was just being a smartass. There's an interesting Wikipedia
article all about the ellipsis. http://en.wikipedia.org/wiki/Ellipsis
But reverse engineering can be done to anything. A copyright message is
all
you need to 'stop' it but that isn't usually enough. I myself have been
designing for 20+ years and have purposefully released things as GPL so
they
can be public. Other stuff (hardware and software) is most defiantly
not
public. I have some rather flash UARTS, Ethernet Interfaces and E1
units.
These add value to both my pay-packet each month and to my companies
standing. They also make sure that each company review, there is a
reason
to keep me employed. I've also started studying towards a BE-Tech and
possibly a Masters. So why do I think its not OK to copy? There are
multiple reasons above.
The only time I would recommend breaking a copyright is when the company
is
defunct and you need to do an update but even then someone might have
walked
away with the copyright/patent.
Simon
OK, but if 'reverse engineering' is just finding out how something works,
then that's fine, yes? For example, books are copyrighted, but you can
still
read them. As to what you then do with the knowledge you gain, I guess
that's where the line between good and evil is. If you read a copyrighted
electronics text book, it's ok to use the knowledge you gain to design
electronics, or even to write your own textbook, provided you don't copy
verbatim. If you reverse engineer a FIR filter, it's ok (legally and
morally?) to use the knowledge you've gained to create your own, provided
it's not a direct copy. Maybe! In the US, maybe the DMCA has some
ramifications as to the legality of reverse engineering.
Interesting subject, I guess there's not a black and white answer.
Cheers, Syms.
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Symon
Guest
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| Posted:
Wed Dec 07, 2005 1:15 am Post subject:
Re: FPGA : Decimation Filter Implementation |
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"Simon Peacock" <simon$actrix.co.nz> wrote in message
news:43952591@news2.actrix.gen.nz...
| Quote: | Of course, the invention of time travel will make all patents null and
void
:-)
Including the patent on the time travel machine?!! |
Cheers, Syms. |
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David Brown
Guest
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| Posted:
Wed Dec 07, 2005 9:15 am Post subject:
Re: FPGA : Decimation Filter Implementation |
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Simon Peacock wrote:
| Quote: | Yews and no.. it could be argued that books are by design, designed to be
read. Take a look at the copyright message for most software. "cannot be
disassembled for any purpose" is a very common phrase
"In order to protect them you may not decompile, reverse engineer,
disassemble, or otherwise reduce the Software to a human-perceivable form."
|
That sort of phrase is common in EULAs, not copyright messages. And in
most countries, it is legally unenforceable (IANAL, of course). In
fact, you'd have a great deal of trouble finding a software EULA that is
entirely legally enforceable in any jurisdiction. Reverse engineering
is a perfectly legal technique for certain purposes (interoperability
with other software is a prime example - look at samba), and
disassembly, etc., is part of that. Of course, directly copying an
existing system is generally illegal, whether by reverse engineering or
otherwise.
| Quote: | This is from the Xilinx EULA for the development tools. I don't have
core-generator handy, but as you can see, they don't want you to view in any
shape or form their software. Altera might be different but that is because
their tools were built with or include GNU
You can of course copy directly from a book, I think anyone would be hard
pressed to stop someone or even to prove they had exclusive rights to
something found in print, you would only have to find it in a different book
printed before the one in question to automatically invalidate any clams.
Of course, the invention of time travel will make all patents null and void
:-)
Simon
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bijoy
Guest
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| Posted:
Thu Dec 08, 2005 9:15 am Post subject:
Re: FPGA : Decimation Filter Implementation |
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Hi all I don't mean reverse engineering... in actual sense.
I need a Decimation filter structure where i can update my coefficients(ie access is provided to the user to update filter coefficient, which is not provided in xilinx core generated module). I have a structure of FIR filter built by me, but that uses more resources than provided by xilinx core generator.
As all of us know the decimation structure there is nothing great in that.
But how to use xilinx block ram to exploit the symmetry of the coefficient may not be known to all. I am looking for a filter structure not VHDL/Verilog code.
I will be very glad to use xilinx provided cores if it suits my requirement of coefficient updation, unfortunately they are not supporting it.
regards bijoy |
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akcooper8@gmail.com
Guest
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| Posted:
Mon Dec 26, 2005 9:15 am Post subject:
Re: FPGA : Decimation Filter Implementation |
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hey bijoy
i am trying to implement a DDC with the xilinx virtex II-pro XUPV2P
board. since you have started on an FPGA project, and are in the
process of optimizing, i was wondering if you could help me in figuring
out how to interface LVDS/CMOS i/o - data to be demodulated - with
system generator or edk. i greatly appreciate your help.
Ashwin |
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