Re: [Discuss-gnuradio] CIC stop band
I'm using 4rx_0tx.rbf. Thanks for your help, Hans - Original Message - From: Eric Blossom [EMAIL PROTECTED] To: Hans Glitsch [EMAIL PROTECTED] Cc: gnuradio mailing list discuss-gnuradio@gnu.org Sent: Thursday, May 17, 2007 8:04 PM Subject: Re: [Discuss-gnuradio] CIC stop band On Thu, May 17, 2007 at 08:06:22AM -0700, Hans Glitsch wrote: Hello, Thank you for the graphs. I wasn't aware that there was a HBF after the CIC. Yes, I'd like to know the frequency response of the whole usrp from input to output when I decimate by 250. Thank you to everyone for the help so far, Hans Hans, Are you using the 2rxhb_2tx.rbf (the default) or the 4rx_0tx.rbf fpga configuration? If it's the 4rx version, there is only the CIC, no halfband. The default 2rxhb_2tx has the halfband after the CIC. Eric -- No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.467 / Virus Database: 269.7.1/807 - Release Date: 5/16/2007 6:05 PM -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean. ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] CIC stop band
Hans: I don't think you really want the CIC transfer function but the transfer function of the convolution of the half band filters and the CIC since that is the total transfer function through the FPGA. Am I right? Bob Hans Glitsch wrote: Hello, What is the stop band of the FPGA CIC filter? How do I figure out the attenuation at a given frequency outside my bandwidth? I'm decimating by 250. Thanks, Hans -- AMSAT Director and VP Engineering. Member: ARRL, AMSAT-DL, TAPR, Packrats, NJQRP, QRP ARCI, QCWA, FRC. ARRL SDR WG Chair If you're going to be crazy, you have to get paid for it or else you're going to be locked up. Hunter S. Thompson ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] CIC stop band
Hello, Thank you for the graphs. I wasn't aware that there was a HBF after the CIC. Yes, I'd like to know the frequency response of the whole usrp from input to output when I decimate by 250. Thank you to everyone for the help so far, Hans - Original Message - From: Firas abbas To: Hans Glitsch Cc: gnuradio mailing list ; Eric Blossom Sent: Wednesday, May 16, 2007 11:19 PM Subject: Re: [Discuss-gnuradio] CIC stop band Dear Hans, I think you meant the frequency response of CIC+ HBF filters. However, the USRP CIC decimation filter has 4 stages. I did MATLAB analysis for 4 stages CIC filter with decimation rate of 250 (as you requested) without the HBF. The spectrum analysis result is attached. The first plot is for entire range [0 to Fs/2]. The second one is zoomed near the interested band. You will see a huge theoretical gain (more than 190 dB) because of CIC bit growth. Firas Eric Blossom [EMAIL PROTECTED] wrote: On Wed, May 16, 2007 at 04:00:24PM -0700, Hans Glitsch wrote: Hello, What is the stop band of the FPGA CIC filter? How do I figure out the attenuation at a given frequency outside my bandwidth? I'm decimating by 250. Thanks, Hans It's a fourth order CIC. See http://users.snip.net/~donadio/cic.pdf for the transfer function. Eric ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio -- -- -- Internal Virus Database is out-of-date. Checked by AVG Free Edition. Version: 7.5.467 / Virus Database: 269.6.5/792 - Release Date: 5/6/2007 9:01 PM -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean. ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] CIC stop band
Hello, I can give you a precise MATLAB based simulated USRP frequency response. All what I need is the HBF coefficients. So this is an open invitation to our dear Matt to give us his designed USRP HBF coefficients or frequency response. Firas, Hans Glitsch wrote: Hello, Thank you for the graphs. I wasn't aware that there was a HBF after the CIC. Yes, I'd like to know the frequency response of the whole usrp from input to output when I decimate by 250. Thank you to everyone for the help so far, Hans - Original Message - From: Firas abbas To: Hans Glitsch Cc: gnuradio mailing list ; Eric Blossom Sent: Wednesday, May 16, 2007 11:19 PM Subject: Re: [Discuss-gnuradio] CIC stop band Dear Hans, I think you meant the frequency response of CIC+ HBF filters. However, the USRP CIC decimation filter has 4 stages. I did MATLAB analysis for 4 stages CIC filter with decimation rate of 250 (as you requested) without the HBF. The spectrum analysis result is attached. The first plot is for entire range [0 to Fs/2]. The second one is zoomed near the interested band. You will see a huge theoretical gain (more than 190 dB) because of CIC bit growth. Firas Eric Blossom [EMAIL PROTECTED] wrote: On Wed, May 16, 2007 at 04:00:24PM -0700, Hans Glitsch wrote: Hello, What is the stop band of the FPGA CIC filter? How do I figure out the attenuation at a given frequency outside my bandwidth? I'm decimating by 250. Thanks, Hans It's a fourth order CIC. See http://users.snip.net/~donadio/cic.pdf for the transfer function. Eric ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio -- -- -- Internal Virus Database is out-of-date. Checked by AVG Free Edition. Version: 7.5.467 / Virus Database: 269.6.5/792 - Release Date: 5/6/2007 9:01 PM -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean. ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio -- View this message in context: http://www.nabble.com/wise-big-block-interleaving-in-GNURadio-tf3768964.html#a10666406 Sent from the GnuRadio mailing list archive at Nabble.com. ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] CIC stop band
On 5/17/07, Eng. Firas [EMAIL PROTECTED] wrote: Hello, I can give you a precise MATLAB based simulated USRP frequency response. All what I need is the HBF coefficients. So this is an open invitation to our dear Matt to give us his designed USRP HBF coefficients or frequency response. Reading the documentation in the Verilog source file is helpful: http://gnuradio.org/trac/browser/gnuradio/trunk/usrp/fpga/sdr_lib/hb/halfband_decim.v The coefficient ROM is located here: http://gnuradio.org/trac/browser/gnuradio/trunk/usrp/fpga/sdr_lib/hb/coeff_rom.v Firas Brian ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] CIC stop band
Eng. Firas wrote: Hello, I can give you a precise MATLAB based simulated USRP frequency response. All what I need is the HBF coefficients. So this is an open invitation to our dear Matt to give us his designed USRP HBF coefficients or frequency response. Firas, The coefficients are here: http://gnuradio.org/trac/browser/gnuradio/trunk/usrp/fpga/sdr_lib/hb/coeff_rom.v Matt ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] CIC stop band
Thank you Brian Matt Using Matt HBF coefficients given by the verilog file [coeff_rom.v], I did the HBF frequency response analysis by MATLAB FDATOOL. Attached is the USRP HBF result frequency response. As we can see, there is a 6 dB passband gain. In my next step, I will try to provide the frequency response of the cascaded USRP CIC+HBF sections. Regards, Firas http://www.nabble.com/file/8495/USRP%20HBF.JPG USRP HBF.JPG Matt wrote: Hello, I can give you a precise MATLAB based simulated USRP frequency response. All what I need is the HBF coefficients. So this is an open invitation to our dear Matt to give us his designed USRP HBF coefficients or frequency response. Firas, The coefficients are here: http://gnuradio.org/trac/browser/gnuradio/trunk/usrp/fpga/sdr_lib/hb/coeff_rom.v Matt Brian Padalino wrote: On 5/17/07, Eng. Firas [EMAIL PROTECTED] wrote: Hello, I can give you a precise MATLAB based simulated USRP frequency response. All what I need is the HBF coefficients. So this is an open invitation to our dear Matt to give us his designed USRP HBF coefficients or frequency response. Reading the documentation in the Verilog source file is helpful: http://gnuradio.org/trac/browser/gnuradio/trunk/usrp/fpga/sdr_lib/hb/halfband_decim.v The coefficient ROM is located here: http://gnuradio.org/trac/browser/gnuradio/trunk/usrp/fpga/sdr_lib/hb/coeff_rom.v Firas Brian ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio -- View this message in context: http://www.nabble.com/wise-big-block-interleaving-in-GNURadio-tf3768964.html#a10667330 Sent from the GnuRadio mailing list archive at Nabble.com. ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] CIC stop band
On Thu, May 17, 2007 at 08:06:22AM -0700, Hans Glitsch wrote: Hello, Thank you for the graphs. I wasn't aware that there was a HBF after the CIC. Yes, I'd like to know the frequency response of the whole usrp from input to output when I decimate by 250. Thank you to everyone for the help so far, Hans Hans, Are you using the 2rxhb_2tx.rbf (the default) or the 4rx_0tx.rbf fpga configuration? If it's the 4rx version, there is only the CIC, no halfband. The default 2rxhb_2tx has the halfband after the CIC. Eric ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] CIC stop band
On Wed, May 16, 2007 at 04:00:24PM -0700, Hans Glitsch wrote: Hello, What is the stop band of the FPGA CIC filter? How do I figure out the attenuation at a given frequency outside my bandwidth? I'm decimating by 250. Thanks, Hans It's a fourth order CIC. See http://users.snip.net/~donadio/cic.pdf for the transfer function. Eric ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio