|Subject:||Re: [Discuss-gnuradio] aUaUaUaUaUaU and requested rx frequency not supported problem|
|Date:||Fri, 11 May 2012 13:34:19 -0400|
On Fri, 11 May 2012 19:08:38 +0200 (CEST), address@hidden wrote:
Hi Everybody, I am using USRP with daugherboard of range 1MHz to 250MHz. I am running the program with gnu-radio 3.6.0 on Ubuntu 11.10. I am trying to run the basic fm receiver program as shown in the video. http://www.youtube.com/watch?v=KWeY2yqwVA0 Whenever I try to execute the code, I get following things on grc. I have double checked that the daughterboard works for the range. When I see the fft plot of the received signal I see that I have just noise all around. The hardware does not support the requested RX frequency: Target frequency: 100.000000 MHz Actual frequency: -28.000000 MHz aUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaU I have also tried to see if the antenna choices are correct. I checked it with uhd_usrp_probe The important part of the result was RX Subdev: AB | | | | Name: Basic RX (0x0001) - AB | | | | Antennas: | | | | Sensors: | | | | Freq range: -250.000 to 250.000 Mhz | | | | Gain Elements: None | | | | Connection Type: IQ | | | | Uses LO offset: No | | | _____________________________________________________ | | | / | | | | RX Subdev: BA | | | | Name: Basic RX (0x0001) - BA | | | | Antennas: | | | | Sensors: | | | | Freq range: -250.000 to 250.000 Mhz | | | | Gain Elements: None | | | | Connection Type: QI | | | | Uses LO offset: No So, when I try to work with uhd_fft. I got same problem with following results uhd_fft --spec B:AB linux; GNU C++ version 4.6.1; Boost_104601; UHD_003.004.001-39-unstable -- Opening a USRP1 device... -- Using FPGA clock rate of 64.000000MHz... Using Volk machine: ssse3_64 UHD Warning: The hardware does not support the requested RX frequency: Target frequency: 100.000000 MHz Actual frequency: -28.000000 MHz Could you help me out here? Thanks in advance. -- Pranav Sakulkar _______________________________________________ Discuss-gnuradio mailing list address@hidden https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
The aU is because your audio subsystem is experiencing underruns, probably because you have a sample-rate issue in your flow-graph.
The UHD warning is because the BASIC_RX has no downconversion hardware at all, which means that any frequency above Nyquist (32Mhz for USRP1 and 50Mhz for N2XX) requires that the FPGA/ADCs sample the appropriate alias frequency, and UHD is warning you that's what it's doing. But without analog filtering in the front-end, you'll end up with *unwanted* aliases as well. The BASIC_RX is very "BASIC", and it's really intended as an interface card to "proper" RF front-ends, with filtering, and probably downconversion to an IF.
|[Prev in Thread]||Current Thread||[Next in Thread]|