[USRP-users] RFNoC OFDM FPGA Build error on X310
Hello, I have been trying to build FPGA image for the RFNoC OFDM blocks - schmidl_cox, eq and ofdm_constellation demapper. I have tried different combination of build with just schimdl_cox or eq or ofdm_constellation_demapper: 1) For eq build, I always got the following error: ERROR: [Opt 31-2] SRLC32E x300_core/inst_eq/inst_axi_wrapper/header_fifo/fifo_short/gen_srlc32e[64].srlc32e is missing a connection on D pin. 2) For schmidl_cox or ofdm_constellation_demapper, I got the following problem: ERROR: [Builder 0-0] The design did not satisfy timing constraints. (Implementation outputs were still generated) Can anyone help with these issues? Thanks, Huacheng ___ USRP-users mailing list USRP-users@lists.ettus.com http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
[USRP-users] Bursty packet transmission
Hi,
I am using USRP N210 for bursty packet transmission, and have difficulty to
understand "tx_md.end_of_burst = true" in C++ code. I am attaching my code
at the end and hope someone can help.
The problem is:
1. when I comment out "tx_md.end_of_burst = true" and use the function for
transmission periodically, my receiver can decode the packet successfully.
But it seems that it can only detect N - 1 packet, where N is the number of
packets that I sent at the transmitter. For example, when I send 3 packets,
the receiver can only decode 2 packets, and so forth. Not sure what is the
reason behind this.
2. When I uncomment "tx_md.end_of_burst = true" (either the one inside the
WHILE loop or outside one), my receiver cannot decode the packets anymore.
When I use spectrum analyzer to see the signal, I can see that the
transmitter does send the signal into the air and the waveform shape looks
right. However, the signal cannot be decoded.
Any suggestions?
Thank you!
Hua
=
size_t sdr_dev::usrp_transmit(vector*> tx_buff_ptr, size_t
requested_num_samps) {
tx_md.start_of_burst = true;
tx_md.end_of_burst = false;
tx_md.has_time_spec = false;
tx_md.time_spec = uhd::time_spec_t(1.0); //0.1
//the first call to send() will block this many seconds before sending:
timeout = seconds_in_future + 0.1; //timeout (delay before transmit +
padding)
vector*> tx_buff_ptr_tmp = tx_buff_ptr;
size_t acc_num_samps = 0; //number of accumulated samples
size_t total_num_samps = requested_num_samps;
while(acc_num_samps < total_num_samps) {
size_t samps_to_send = total_num_samps - acc_num_samps;
if (samps_to_send > tx_max_num_samps) {
samps_to_send = tx_max_num_samps;
}
else {
//tx_md.end_of_burst = true;
}
for (int i = 0; i < tx_buff_ptr.size(); i++) tx_buff_ptr_tmp[i] =
_buff_ptr[i][acc_num_samps];
//send a single packet
size_t num_tx_samps = tx_stream->send(tx_buff_ptr_tmp,
samps_to_send, tx_md, timeout);
//do not use time spec for subsequent packets
tx_md.has_time_spec = false;
tx_md.start_of_burst = false;
acc_num_samps += num_tx_samps;
}
//tx_md.end_of_burst = true;
tx_stream->send("", 0, tx_md);
return acc_num_samps;
}
==
___
USRP-users mailing list
USRP-users@lists.ettus.com
http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
[USRP-users] Questions regarding BasicTX Daughterboard
Dear All:
I have some questions regarding BasicTX Daughterboard. It seems that this
board does not have complex design such as analog mixer. But it can be set
with a carrier frequency in GNU Radio. My questions are:
1) When I use this daughterboard and set its carrier frequency to nonzero
(e.g., 50 MHz), is the frequency up-conversion done in the digital domain
by the motherboard's FPGA?
2) If I use this daughterboard in IQ mode (i.e., setting frontend to AB),
what are the output signal at antenna ports Tx-A and Tx-B? Denote S(t) as
the digital baseband signal and fc as the carrier frequency specified in
GNU Radio, are the output signals at Tx-A and Tx-B ports
Re{S(t)}*cos(2*pi*fc*t) and Im{S(t)}*sin(2*pi*fc*t), respectively? If not,
what is the output signals at those two antenna ports?
Thank you in advance!
Hua
___
USRP-users mailing list
USRP-users@lists.ettus.com
http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
[USRP-users] N210 transmits and receives using the same antenna
Hi All: I am using N210 (with SBX daughter board) to test the channel reciprocity. I wish to transmit signal using antenna "Tx/Rx" in time slot 1, and then receive signal using the same antenna in time slot 2, and so on so forth. I can do this manually, but do not know how to do it by programming (either using GR or OOT C++ blocks). Any one can help? Thanks in advance! Hua ___ USRP-users mailing list USRP-users@lists.ettus.com http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
