Re: [Discuss-gnuradio] testing outside building with our USRPs
On Mon, Dec 1, 2008 at 4:20 PM, Bill Stevenson [EMAIL PROTECTED] wrote: Hello, all! ... But how can we get power for USRPs when we are testing outside? Could anybody tell me a decent way to power USRPs up without connecting the power cable to the extension board inside the building? What kind of batterypack can we use for the USRPs if battery is doable? Thanks a lot! a) Use sealed 6v batteries. Get a charger when you buy the batteries. Check the mAh rating to make sure you'll get the runtime you need. Try to avoid using them in parallel unless you have to. b) Use car batteries plus inverters (or even cars, inverters and a couple long extension cables). Heavy, expensive, inefficient, but you might have the kit already. Regards, Blair. ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] testing outside building with our USRPs
Heavy, expensive, inefficient, but you might have the kit already. If you are doing fixed measurement, you should also look around the office for some of the computer back up UPS things. They are designed to allow a computer a short time to save and shut down, but can also supply a low draw device several hours (we used them to power label printers). It's something you probably already have that you can just 'borrow' for your experiment. Jason ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
[Discuss-gnuradio] Good Resource on QPSK Carrier Tracking and Baud Tracking Algorithms
Looking for a good resource for QPSK Carrier Tracking and Baud Tracking Algorithms that take complex baseband input. Thanks in advance, Isaac ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
[Discuss-gnuradio] OpenBTS Implementation
Hello, I would like to hear from anyone who has successfully implemented OpenBTS. Best regards, A. Hakeem ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Fw: [Discuss-gnuradio] testing outside building with our USRPs
- Forwarded Message From: Bill Stevenson [EMAIL PROTECTED] To: Blair Strang [EMAIL PROTECTED] Sent: Monday, December 1, 2008 12:13:50 PM Subject: Re: [Discuss-gnuradio] testing outside building with our USRPs From: Blair Strang [EMAIL PROTECTED] To: discuss-gnuradio@gnu.org Sent: Monday, December 1, 2008 2:31:30 AM Subject: Re: [Discuss-gnuradio] testing outside building with our USRPs On Mon, Dec 1, 2008 at 4:20 PM, Bill Stevenson [EMAIL PROTECTED] wrote: Hello, all! But how can we get power for USRPs when we are testing outside? Could anybody tell me a decent way to power USRPs up without connecting the power cable to the extension board inside the building? What kind of batterypack can we use for the USRPs if battery is doable? Thanks a lot! a) Use sealed 6v batteries. Get a charger when you buy the batteries. Check the mAh rating to make sure you'll get the runtime you need. Try to avoid using them in parallel unless you have to. b) Use car batteries plus inverters (or even cars, inverters and a couple long extension cables). Heavy, expensive, inefficient, but you might have the kit already. Regards, Blair. Thank you Blair! Now I know how to power the USRPs, but what is your idea of getting our PCs(Desktop Computers) powered outside? If the only way is to use laptops, 8 laptops should be required. That is really a huge number for us. :) Thank you! Bill ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
[Discuss-gnuradio] adaptive transmit power of RFX2400 daughter board
Hello, all! I am looking into the benchmark_tx.py file under the directory of python/digital. The default value of the --tx-amplitude is 12000 and the transmit power of RFX2400 is 50mW. Is there any relationship between these two numbers? If I changed the --tx-amplitude to be 1200, what is the transmit power in mW? How can I translate the --tx-amplitude to the real transmit power in mW? Thanks a lot!!! Bill ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
[Discuss-gnuradio] the antenna for transmission in 2.48-2.9GHz
Hello, all! We are trying to bypass the ISM band to transmit data, say outside 2.48GHz. But I cannot find a suitable antenna for this kind of transmission on ettus.com, the antenna we are using isVERT2450 which is not ideal outside 2.48GHz. What kind of antenna should we use? Thanks a lot! Bill ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] testing outside building with our USRPs
Bill - I've done this with a 12v deep cycle battery and a good quality 12-6 DC-DC converter. We ran off-grid for a week like that, recharging the battery in place as needed with whatever power sources were handy. -- David On Nov 30, 2008, at 7:20 PM, Bill Stevenson wrote: Hello, all! We are utilizing USRPs to test the transmission range under some certain circumstances, say different modulation schemes. We are planning on testing the range outside, say in a football field since that condition is similar to the free space environment. But how can we get power for USRPs when we are testing outside? Could anybody tell me a decent way to power USRPs up without connecting the power cable to the extension board inside the building? What kind of batterypack can we use for the USRPs if battery is doable? Thanks a lot! Bill ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio David A. Burgess Kestrel Signal Processing, Inc. ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
[Discuss-gnuradio] Build errors on F10 x86_64 with latest trunk
I can't get beyond this error in ./configure --with-boost=$BOOST_PREFIX configure: error: Component usrp: PKGCONFIG cannot find info for usrp, with PKG_CONFIG_PATH = [ NONE/lib64/pkgconfig ] . I've tried installing the yum usrp package, but that didn't help. -- Marcus Leech Principal Investigator, Shirleys Bay Radio Astronomy Consortium http://www.sbrac.org ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] Sounding signal output power and spectrum
On Sat, Nov 29, 2008 at 9:55 AM, Qi Chen [EMAIL PROTECTED] wrote: 1. The gr-sounder default transmit amplitude is 4096, is there a particular reason why this number is chosen? My guess is because a 12-bit DAC is used. You are correct. This app uses a custom FPGA image for transmission, and unlike most GNU Radio applications, the amplitude here is directly converted to the DAC output values. This is the maximum amplitude. 3. I did a indoor measurement with TX-RX separation of 50 meters (w/ LOS), the received channel impulse response has 5 chunks of CIRs instead of one, and the number of samples between each chunk is always 800 chips, I am sure those CIRs are not multipath delays since in an indoor environment the corresponding delays can't be 800-chips apart from each other(way too long). Am I missing something here? You need to post your command line parameters for the transmitter and receiver. -Johnathan ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] Build errors on F10 x86_64 with latest trunk
On Mon, Dec 1, 2008 at 10:11 AM, Marcus D. Leech [EMAIL PROTECTED] wrote: I can't get beyond this error in ./configure --with-boost=$BOOST_PREFIX configure: error: Component usrp: PKGCONFIG cannot find info for usrp, with PKG_CONFIG_PATH = [ NONE/lib64/pkgconfig ] . Hmm. This is the GNU Radio trunk configure script? It shouldn't be checking PKGCONFIG for the usrp library. -Johnathan ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] a report on dqpsk modulation in gnuradio
From: Johnathan Corgan [EMAIL PROTECTED] To: Bill Stevenson [EMAIL PROTECTED] Sent: Thursday, November 27, 2008 3:02:23 AM Subject: Re: [Discuss-gnuradio] a report on dqpsk modulation in gnuradio No problem, Johnathan. After reading this, I did my experimentation in several different configurations. The commands I used in the transmitter and receiver side are: python benchmark_tx.py -f 2479M -r 2000k -m dqpsk -s 100 (-s 800 or -s 1500) python benchmark_rx.py -f 2479M -r 2000k -m dqpsk I still got the same result: when packet size is 100, the PER is around 20% no matter what the distance between two USRPs and transmission power are; when packet size is 800, PER is around 50% and when size is the default value, PER is around 66%. This result is the same as that I got before I updated our gnuradio codes. Could you tell me which demo file you used for your configuration, what your configuration looks like and what kind of commands you used for your Tx and Rx part? Thank you so much!!! Bill On Wed, Nov 26, 2008 at 3:39 PM, Bill Stevenson [EMAIL PROTECTED] wrote: Hello, Johnathan. I have implemented the entire codes in the trunk step by step, but unfortunately this time I cannot receive any correct packets under the dqpsk modulation scheme even after I set the packet size to 40. Actually, before I installed the SVN codes, I was able to get 90% correct packets when I set the packet size to 40 and samples per symbol to 4, but this time it failed sadly. Is there anything going wrong in your new carrier offset tracking tactics? Thank you! This code is working correctly in a number of different configurations in my lab. Unfortunately, I will be out of the office for the rest of the week and early next week, so will be unable to assist you further. -Johnathan ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] Sounding signal output power and spectrum
On Dec 1, 2008, at 2:24 PM, Johnathan Corgan wrote: On Sat, Nov 29, 2008 at 9:55 AM, Qi Chen [EMAIL PROTECTED] wrote: 1. The gr-sounder default transmit amplitude is 4096, is there a particular reason why this number is chosen? My guess is because a 12-bit DAC is used. You are correct. This app uses a custom FPGA image for transmission, and unlike most GNU Radio applications, the amplitude here is directly converted to the DAC output values. This is the maximum amplitude. That makes sense. Do those measured output power values make sense? 3. I did a indoor measurement with TX-RX separation of 50 meters (w/ LOS), the received channel impulse response has 5 chunks of CIRs instead of one, and the number of samples between each chunk is always 800 chips, I am sure those CIRs are not multipath delays since in an indoor environment the corresponding delays can't be 800-chips apart from each other(way too long). Am I missing something here? You need to post your command line parameters for the transmitter and receiver. I am using the default parameters for both tx and rx. My command lines are as follows: Tx: sudo ./usrp_sounder.py -t -f 2.44G -v -D Rx: sudo ./usrp_sounder.py -t -f 2.44G -v -D -F output.dat I use read_complex_binary.m to read the log file. The resulting channel impulse response looks like this: Figure 1: http://www.ittc.ku.edu/~chenqi/cir1.jpg Figure 2: http://www.ittc.ku.edu/~chenqi/cir2.jpg Figure 1 is the first cycle of the recorded impulse response. Figure 2 shows five chunks of CIRs the first and second group of CIRs are 800 chips apart. Any clue on that? -Johnathan ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] Sounding signal output power and spectrum
On Dec 1, 2008, at 4:04 PM, Qi Chen wrote: On Dec 1, 2008, at 2:24 PM, Johnathan Corgan wrote: On Sat, Nov 29, 2008 at 9:55 AM, Qi Chen [EMAIL PROTECTED] wrote: 1. The gr-sounder default transmit amplitude is 4096, is there a particular reason why this number is chosen? My guess is because a 12-bit DAC is used. You are correct. This app uses a custom FPGA image for transmission, and unlike most GNU Radio applications, the amplitude here is directly converted to the DAC output values. This is the maximum amplitude. That makes sense. Do those measured output power values make sense? 3. I did a indoor measurement with TX-RX separation of 50 meters (w/ LOS), the received channel impulse response has 5 chunks of CIRs instead of one, and the number of samples between each chunk is always 800 chips, I am sure those CIRs are not multipath delays since in an indoor environment the corresponding delays can't be 800-chips apart from each other(way too long). Am I missing something here? You need to post your command line parameters for the transmitter and receiver. I am using the default parameters for both tx and rx. My command lines are as follows: Tx: sudo ./usrp_sounder.py -t -f 2.44G -v -D Rx: sudo ./usrp_sounder.py -t -f 2.44G -v -D -F output.dat Oops, correction: Rx: sudo ./usrp_sounder.py -r -f 2.44G -v -D -F output.dat. Simple copy and past typo. I use read_complex_binary.m to read the log file. The resulting channel impulse response looks like this: Figure 1: http://www.ittc.ku.edu/~chenqi/cir1.jpg Figure 2: http://www.ittc.ku.edu/~chenqi/cir2.jpg Figure 1 is the first cycle of the recorded impulse response. Figure 2 shows five chunks of CIRs the first and second group of CIRs are 800 chips apart. Any clue on that? -Johnathan ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] testing outside building with our USRPs
David - Thank you, I understand it! But how did you get your computer powered when you were doing experiment outside? The laptops in our lab are very limited. Thank you! Bill From: David Burgess [EMAIL PROTECTED] To: Bill Stevenson [EMAIL PROTECTED] Cc: discuss-gnuradio@gnu.org Sent: Monday, December 1, 2008 12:02:39 PM Subject: Re: [Discuss-gnuradio] testing outside building with our USRPs Bill - I've done this with a 12v deep cycle battery and a good quality 12-6 DC-DC converter. We ran off-grid for a week like that, recharging the battery in place as needed with whatever power sources were handy. -- David On Nov 30, 2008, at 7:20 PM, Bill Stevenson wrote: Hello, all! We are utilizing USRPs to test the transmission range under some certain circumstances, say different modulation schemes. We are planning on testing the range outside, say in a football field since that condition is similar to the free space environment. But how can we get power for USRPs when we are testing outside? Could anybody tell me a decent way to power USRPs up without connecting the power cable to the extension board inside the building? What kind of batterypack can we use for the USRPs if battery is doable? Thanks a lot! Bill ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio David A. Burgess Kestrel Signal Processing, Inc. ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
[Discuss-gnuradio] problem of demodulation
Hi: Lately, I encountered a problem with tx/rv packets by using tunnel.py script. In 2.4GHz band, there are two nodes trying to ping with each other. GNUradio node A can receive ping message but the node B can't. So I check the rx-power-log and see the power level of both nodes have similar strength. However, when I check the demodulation log file, node B cannot demodulate the message correctly cause most of the signal are below some threshold. Does anyone know why node B cannot demodulate the packets correctly? The weird thing is when I use another node C to transmit packet to node B, B can be pinged successfully by C. So I guess the hardware of node B and the script should be normal but don't know what happen. Any suggestions will be appreciated! Thanks! KC ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] testing outside building with our USRPs
David- Thank you for your information about the laptop power rig. But our problem is we have to use eight USRPs as our nodes in our experimentation, and we do not have so many laptops, so do you know how to get 110-220 voltage input for our computers when testing outside? Thank you! Bill From: David Burgess [EMAIL PROTECTED] To: Bill Stevenson [EMAIL PROTECTED] Sent: Monday, December 1, 2008 6:59:00 PM Subject: Re: [Discuss-gnuradio] testing outside building with our USRPs Bill - I got a laptop power rig designed for automotive and air travel and then I wired a cigarette-lighter-style socket to the battery. You can get everything you need for that at any autoparts store. Also remember that a lead-acid battery runs anywhere from 12-14 volts depending on its charge state. If you charge in place, you should also be aware that some chargers might run up to 16 volts or more in some modes, so know your equipment before you try it. (But if you don't need continuous operation, you don't need to charge in place.) -- David On Dec 1, 2008, at 3:23 PM, Bill Stevenson wrote: David - Thank you, I understand it! But how did you get your computer powered when you were doing experiment outside? The laptops in our lab are very limited. Thank you! Bill From: David Burgess [EMAIL PROTECTED] To: Bill Stevenson [EMAIL PROTECTED] Cc: discuss-gnuradio@gnu.org Sent: Monday, December 1, 2008 12:02:39 PM Subject: Re: [Discuss-gnuradio] testing outside building with our USRPs Bill - I've done this with a 12v deep cycle battery and a good quality 12-6 DC-DC converter. We ran off-grid for a week like that, recharging the battery in place as needed with whatever power sources were handy. -- David On Nov 30, 2008, at 7:20 PM, Bill Stevenson wrote: Hello, all! We are utilizing USRPs to test the transmission range under some certain circumstances, say different modulation schemes. We are planning on testing the range outside, say in a football field since that condition is similar to the free space environment. But how can we get power for USRPs when we are testing outside? Could anybody tell me a decent way to power USRPs up without connecting the power cable to the extension board inside the building? What kind of batterypack can we use for the USRPs if battery is doable? Thanks a lot! Bill ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio David A. Burgess Kestrel Signal Processing, Inc. David A. Burgess Kestrel Signal Processing, Inc. ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
[Discuss-gnuradio] Inquiry about automatic gain control
I am trying to achieve a goal of controlling the AGC, please help. Here is what I have so far, for the automatic gain control (AGC): I have found in the module adc_interface (which is in fpga\sdr_lib\adc_interface) a comment about level sensing for the AGC. I am assuming the module rssi and module adc_interface is where the AGC is controlled? If not where do I go about turning on or off the AGC. The rssi is used to sense the signal strength in the fpga and that is feedback to the ADC which controls the AGC, is that correct? After I know how to turn on and off the AGC, how do I adjust the gain of the amplifier? If I wanted to make a block diagram, or refer to a schematic that involves the AGC, where should I start? Is the AGC located before the ADC, and the ADC is contained in the fpga, right? Thank you so much for your time and help, Benjamin Dannan ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] Inquiry about automatic gain control
On Mon, Dec 1, 2008 at 10:53 PM, [EMAIL PROTECTED] wrote: I am trying to achieve a goal of controlling the AGC, please help. Here is what I have so far, for the automatic gain control (AGC): I have found in the module adc_interface (which is in fpga\sdr_lib\adc_interface) a comment about level sensing for the AGC. I am assuming the module rssi and module adc_interface is where the AGC is controlled? If not where do I go about turning on or off the AGC. The rssi is used to sense the signal strength in the fpga and that is feedback to the ADC which controls the AGC, is that correct? I don't believe there is any AGC actually going on at all. Please see here: http://gnuradio.org/trac/ticket/66 After I know how to turn on and off the AGC, how do I adjust the gain of the amplifier? You need to familiarize yourself with the gain settings of the different daughterboards and how their gains are controlled. The Python db code is probably a good place to start looking. If I wanted to make a block diagram, or refer to a schematic that involves the AGC, where should I start? Is the AGC located before the ADC, and the ADC is contained in the fpga, right? The ADC is an external chip. The data feeds into the FPGA where it is then processed. Thank you so much for your time and help, Good luck. Brian ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] Some USRP2 Questions
13) With Basic TX board, USRP1 can generate maximum of 44 MHz frequency, What USRP2 is capable of ? 44 MHz is the highest frequency in the first nyquist zone on the USRP1. Much higher frequencies can be used in the higher zones. The USRP2 takes 100 MS/s rates and interpolates up to 400 MS/s. Direct frequencies up to ~170 MHz should be usable. 14) What is USRP2 overrun message? Currently overruns are shown on the UART port, not on the host. They are shown with a O. The reality is that you should never see them. If the host computer can't keep up you will see S messages in the terminal on the host, standing for sequence number error. 15) What is USRP2 underrun message? Underruns are shown on the UART port as U. 16) What are the most important (hot) trunk USRP2 code that we need to check to understand USRP2 architecture, configuration and operation? In the FPGA code, the tx_control.v and rx_control.v show inband signalling, dsp_core_rx and dsp_core_tx show the DSP, and u2_core.v is the top level. In the firware, start with txrx.c. 17) How much USRP2 FPGA resources does the currently FPGA firmware needs? 37 out of 40 block RAMs, 16 or 18 of the 40 multipliers, and about 35 to 40% of the logic area. Matt ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] Inquiry about automatic gain control
Brian, If you refer to the usrp\fpga\sdr_lib\adc_interface.v this is a comment stating: \\level sensing for AGC on line 67 of the verilog code file. I have read on the wiki that AGC can be implemented by moving resistors around, can you elaborate on this: which resistors, and on what board? I am assuming that there is some sort of feedback loop for the FPGA to an amplifier which uses the RSSI, is there not one? Thanks for your time and help. -Benjamin Dannan Quoting Brian Padalino [EMAIL PROTECTED]: On Mon, Dec 1, 2008 at 10:53 PM, [EMAIL PROTECTED] wrote: I am trying to achieve a goal of controlling the AGC, please help. Here is what I have so far, for the automatic gain control (AGC): I have found in the module adc_interface (which is in fpga\sdr_lib\adc_interface) a comment about level sensing for the AGC. I am assuming the module rssi and module adc_interface is where the AGC is controlled? If not where do I go about turning on or off the AGC. The rssi is used to sense the signal strength in the fpga and that is feedback to the ADC which controls the AGC, is that correct? I don't believe there is any AGC actually going on at all. Please see here: http://gnuradio.org/trac/ticket/66 After I know how to turn on and off the AGC, how do I adjust the gain of the amplifier? You need to familiarize yourself with the gain settings of the different daughterboards and how their gains are controlled. The Python db code is probably a good place to start looking. If I wanted to make a block diagram, or refer to a schematic that involves the AGC, where should I start? Is the AGC located before the ADC, and the ADC is contained in the fpga, right? The ADC is an external chip. The data feeds into the FPGA where it is then processed. Thank you so much for your time and help, Good luck. Brian ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] Inquiry about automatic gain control
Brian, Can AGC be implemented in code, on the verilog side using the FPGA? Thanks -Benjamin uoting Brian Padalino [EMAIL PROTECTED]: On Mon, Dec 1, 2008 at 10:53 PM, [EMAIL PROTECTED] wrote: I am trying to achieve a goal of controlling the AGC, please help. Here is what I have so far, for the automatic gain control (AGC): I have found in the module adc_interface (which is in fpga\sdr_lib\adc_interface) a comment about level sensing for the AGC. I am assuming the module rssi and module adc_interface is where the AGC is controlled? If not where do I go about turning on or off the AGC. The rssi is used to sense the signal strength in the fpga and that is feedback to the ADC which controls the AGC, is that correct? I don't believe there is any AGC actually going on at all. Please see here: http://gnuradio.org/trac/ticket/66 After I know how to turn on and off the AGC, how do I adjust the gain of the amplifier? You need to familiarize yourself with the gain settings of the different daughterboards and how their gains are controlled. The Python db code is probably a good place to start looking. If I wanted to make a block diagram, or refer to a schematic that involves the AGC, where should I start? Is the AGC located before the ADC, and the ADC is contained in the fpga, right? The ADC is an external chip. The data feeds into the FPGA where it is then processed. Thank you so much for your time and help, Good luck. Brian ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] Inquiry about automatic gain control
[EMAIL PROTECTED] wrote: Brian, If you refer to the usrp\fpga\sdr_lib\adc_interface.v this is a comment stating: \\level sensing for AGC on line 67 of the verilog code file. I have read on the wiki that AGC can be implemented by moving resistors around, can you elaborate on this: which resistors, and on what board? I am assuming that there is some sort of feedback loop for the FPGA to an amplifier which uses the RSSI, is there not one? By moving some resistors around you can implement a completely analog AGC function on the RFX900, 1200, 1800, and 2400. It will not work on the RFX400. In general, there are many ways you can implement AGC, depending on where you implement the RSSI sensing and the control functions. Nothing has been done to prevent you from doing any of these, but it is an exercise left to the user, as they say. Matt ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] Inquiry about automatic gain control
Matt, So it is possible to be implemented in code on the verilog side? If so, do you have any suggestions on where to start? Thanks for your help Regards, Benjamin Dannan Quoting Matt Ettus [EMAIL PROTECTED]: [EMAIL PROTECTED] wrote: Brian, If you refer to the usrp\fpga\sdr_lib\adc_interface.v this is a comment stating: \\level sensing for AGC on line 67 of the verilog code file. I have read on the wiki that AGC can be implemented by moving resistors around, can you elaborate on this: which resistors, and on what board? I am assuming that there is some sort of feedback loop for the FPGA to an amplifier which uses the RSSI, is there not one? By moving some resistors around you can implement a completely analog AGC function on the RFX900, 1200, 1800, and 2400. It will not work on the RFX400. In general, there are many ways you can implement AGC, depending on where you implement the RSSI sensing and the control functions. Nothing has been done to prevent you from doing any of these, but it is an exercise left to the user, as they say. Matt ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] testing outside building with our USRPs
On Tuesday 02 December 2008 13:23:49 Bill Stevenson wrote: Thank you for your information about the laptop power rig. But our problem is we have to use eight USRPs as our nodes in our experimentation, and we do not have so many laptops, so do you know how to get 110-220 voltage input for our computers when testing outside? Thank you! You could parallel up a few car batteries and run the PCs off an inverter. The power requirements are variable depending on your PCs of course :) -- Daniel O'Connor software and network engineer for Genesis Software - http://www.gsoft.com.au The nice thing about standards is that there are so many of them to choose from. -- Andrew Tanenbaum GPG Fingerprint - 5596 B766 97C0 0E94 4347 295E E593 DC20 7B3F CE8C signature.asc Description: This is a digitally signed message part. ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] Some USRP2 Questions
Hi Matt, Thank you for the answers. I will try to add them to USRP2 FAQ Wiki. One thing is not clear which is the TX path interpolation. In RX path: if ADC sampling = 100MHz, and if Min decimation = 4 = max IF bandwidth = 25MHz = Max IF Ethernet rate = 4 bytes per sample * 25 MSPS = 100 Mbyte/sec = 800 Mbit/sec (Every thing is clear) But this is not clear in TX path because: If Max IF Ethernate rate = 100 Mbyte/sec = Max TX IF bandwidth = 25 MHz and if min interpolation = 4 (as you said in your previous email) = DAC will get 100 MSPS But USRP2 DAC is clocked at 400 MHz, so where is the other missing interpolation by 4 in the TX chain? Best Regards, Firas -- View this message in context: http://www.nabble.com/Some-USRP2-Questions-tp20729711p20786100.html 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
[Discuss-gnuradio] code for configuring usrp with 2 transmitting and 2 receiving antennas?
Dear All, I was wondering if someone could point me to code for configuring a usrp with 2 transmitting and 2 receiving antennas. I tried to make some code by copying certain parts in multi_file.py, and it seems to be working to some degree, but I am not sure, because multi_file.py seems to be for receiving from 4 antennas. Thanks! Best regards, Zenny ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] Maximum RF Input Power
Santix wrote: Hi, I have been testing my USRP - Flex2400 with a Signal Generator with values of -30dBm to 20 dBm... Could it have been damaged??? Regads, Santiago Ortega. It is very likely that you damaged it. You put +20dBm into a device that specifies a maximum input power of -20 dBm. Matt ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
