Hi, I want to simulate the radar delay by having real time receive, modulation and transmission of radar signal for ground testing purposes. Therefore, I need 2 TX channel and 1 RX, the first TX is to transmit out the signal to simulate a device transmitting to me elsewhere. Then the RX will take in this signal and do some DSP and then re-transmit back out to the device using the 2nd TX port in the USRP B210. The signal I am tasked to do is a radar signal and I have to transmit out one pulse width of the chirp and wait for certain amount of time before sending another pulse.
Thank you in advanced! -----Original Message----- From: Müller, Marcus (CEL) [mailto:muel...@kit.edu] Sent: Friday, 11 May 2018 3:05 PM To: Yeo Jin Kuang Alvin (IA); discuss-gnuradio@gnu.org Subject: Re: [Discuss-gnuradio] Tx Burst for Chirp signals Could you be a little more specific, please, than "receive, digitize and re-transmit"? For what purpose? Why a chirp? Can you please give us the bigger picture, here? What's the thing you need to build? Best regards, Marcus On Fri, 2018-05-11 at 02:03 +0000, Yeo Jin Kuang Alvin (IA) wrote: > Hello, > > I am currently trying to work on the USRP B210 to act as a > transceiver. Basically, what I am tasked to do is to receive, > digitize, modulate and re-transmit. So what I am planning to do now > is to create a chirp signal in the USRP B210 and transmit back to > itself to the RX port. As a result, I have to send a pulse and stop > for a moment while it is receiving and then transmit again. > > Thank you in advanced! > > -----Original Message----- > From: Müller, Marcus (CEL) [mailto:muel...@kit.edu] > Sent: Thursday, 10 May 2018 9:09 PM > To: Yeo Jin Kuang Alvin (IA); discuss-gnuradio@gnu.org > Subject: Re: [Discuss-gnuradio] Tx Burst for Chirp signals > > sure, but it's not the way I'd recommend for perfectly periodic > transmissions and I'm almost certain this will just lead us further > down your XY problem: https://xyproblem.info > > Can you maybe explain in detail what you need chirps for, why you > need > them at this low repitition rate, what the purpose of all this is? We > might be better at helping you that way. > > thank you, > Marcus > > On Thu, 2018-05-10 at 09:58 +0000, Yeo Jin Kuang Alvin (IA) wrote: > > Hi, > > > > Thank you again. Are there any examples or guides I can refer to > > regarding the tx_time tags? Will this allow me to transmit every > > few > > seconds? > > > > Thank you in advanced! > > > > -----Original Message----- > > From: Müller, Marcus (CEL) [mailto:muel...@kit.edu] > > Sent: Thursday, 10 May 2018 5:34 PM > > To: Yeo Jin Kuang Alvin (IA); discuss-gnuradio@gnu.org > > Subject: Re: [Discuss-gnuradio] Tx Burst for Chirp signals > > > > Hi! > > > > So, you're continuously generating data to send, so it continuously > > sends data – it works as you've designed it. Maybe you want to > > somehow > > add "tx_time" tags every "packet length" samples? > > Also, make sure that one packet really contains one chirp. In your > > previous flow graph, that wasn't the case, so make sure the packet > > length corresponds to the number of samples per chirp. > > > > Best regards, > > Marcus > > > > On Thu, 2018-05-10 at 09:20 +0000, Yeo Jin Kuang Alvin (IA) wrote: > > > Hi, > > > > > > Thanks Marcus! Corrected it and thanks for the info! > > > > > > 1) I would like to transmit burst signals of the chirp > > > generated from the flowgraph attached. I tried using the “stream > > > to > > > Tagged stream” way, but when I ran the GNU Radio Companion, it’s > > > being transmitted continuously. Nothing seems to be happening. > > > Am > > > I > > > doing something wrong and is there a better way for burst > > > transmission? > > > > > > Does anyone know this? > > > > > > Thanks in advanced! > > > > > > -----Original Message----- > > > From: Müller, Marcus (CEL) [mailto:muel...@kit.edu] > > > Sent: Thursday, 10 May 2018 5:06 PM > > > To: Yeo Jin Kuang Alvin (IA); discuss-gnuradio@gnu.org > > > Subject: Re: [Discuss-gnuradio] Tx Burst for Chirp signals > > > > > > Hi! > > > > > > your receiver low pass filter is incorrectly parameterized, > > > probably > > > (sampling rate isn't 32 MS/s). And so is the rest of your flow > > > graph > > > – > > > your USRP is using a sampling rate of 2 MS/s, but you act as if > > > it's > > > running at 32 MS/s. Start with 2 MS/s and make it work with that > > > – > > > then > > > later scale up (the processing load of 32 MS/s is harder than you > > > probably think). > > > Remember that GNU Radio is pure DSP, so all the axis labels on > > > your > > > visualizations are just that – labels, interpreting relative > > > frequencies (i.e. frequencies divided by the sampling rate) by > > > multiplying them with the value you entered in bandwidth. The > > > "physical > > > meaning" of your signal is defined by the sampling rate of your > > > physical device. > > > Thus, you want to use the same sampling rate everywhere in your > > > flow > > > graph. These things mean! something. > > > > > > Best regards, > > > Marcus > > > > > > On Thu, 2018-05-10 at 08:31 +0000, Yeo Jin Kuang Alvin (IA) > > > wrote: > > > > Hi everyone, > > > > > > > > There are two questions that I would like to ask. > > > > > > > > 1) I would like to transmit burst signals of the chirp > > > > generated > > > > from the flowgraph attached. I tried using the “stream to > > > > Tagged > > > > stream” way, but when I ran the GNU Radio Companion, it’s being > > > > transmitted continuously. Nothing seems to be happening. Am I > > > > doing > > > > something wrong and is there a better way for burst > > > > transmission? > > > > > > > > 2) I noticed something with the sampling rates of the > > > > blocks. > > > > When I use the same sampling rate for all the blocks, I get > > > > underflow > > > > “UUU”. However, when I changed all the block’s sampling rate to > > > > 32MHz > > > > and leave the USRP Sink and Source to 2MHz, no underflow is > > > > seen > > > > but > > > > there is still overflow (seen in the attached screenshot). > > > > > > > > What is the difference between the USRP’s sampling rate > > > > compared > > > > to > > > > the other block’s sampling rate? > > > > > > > > Thank you in advanced! > > > > _______________________________________________ > > > > Discuss-gnuradio mailing list > > > > Discuss-gnuradio@gnu.org > > > > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio