I need to make some filters now for some project in FPGA. I was wondering if some free (open source?) software exists that outputs verilog (or a xilinx module for example) with as input say -3dB point, slope, poles, low / high pass etc.? These programs do exist for analog filters, some from IC manufacturers. Is such a thing feasable (to do in verilog) does it exist? Jan
Question about filters and verilog etc..
Dec 12, 2003
3 Replies
Hi Jan,
Our company Tyder has a product ONEoverT and it outputs VHDL which you can use to design filters on FPGAs....FIRs (Windowed & Optimal) loads of other FIR types, and also different types of IIR filters.
It is not free but it is on sale at a very low price. There are some case studies on the website which you can download. You can also download the demo version.
Just use a filter design tool to generate the coefficients. The HDL is pretty simple. ScopeFIR is one example.
Of course, you can also do a lot of this work using tools like Excel from fundamental DSP/Filter theory/math. Excel has a SUMOFPRODUCTS() function that come in handy for some of this work (like implementing a DFT to generate filter frequency response and graph it).
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Martin Euredjian
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On a sunny day (Sat, 13 Dec 2003 07:37:46 GMT) it happened "Martin Euredjian" wrote in :
Hi, I downloaded ScopeFIR, and guess what, it runs fine on wine too, in Linux. So thank you. Then I played a bit with it, now I may perhaps input those coefficients to the FIR I found on opencores. But playing with ScopeFIR I got that 'deja-vue' feeling.... Some time ago I did some FIR in C for a horizontal re-scaler (see paper at
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). Think I did not use that FIR in the end, that project was abandoned when I started using DVD. But in that time I did a whole lot of reading up on digital signal processing and IIR FIR etc.. Now then I used a program in Linux called 'remez' to calculate coefficients. I think ScopeFIR is either from the same author or a blunt copy (windows port) of remez, I dunno. But even the examples and the frequency choice is the same...... So I looked up remez on my machine (google for /root/compile/filters/remez/REMEZ16.EXE if you use windows), I do not remember where I found remez, google remez or remez.c remez uses gnu-plot..... hehe Since ScopeFIR asks 100$ after 60 days, I will be using remez likely after that time. Jan
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