Discussion:
[USRP-users] Gnuradio Companion, USRP-N210, and the Basic Rx Daughterboard
S Corl
2012-03-27 17:08:20 UTC
Permalink
To Summarize: I'm trying to familiarize myself with the USRP N210, my
Basic TX and
Basic RX daughterboards and Gnu Radio.
My efforts to run an FM broadcast receiver as an example are failing
and I'm not sure why. I am able to run uhd_usrp_probe on my device. I
just can't seem to access the full range of frequencies I expect to
with Basic Rx.

When I try running the uhd_wbfm_receive.grc example
(gnuradio-3.5.1/gnuradio-examples/grc/uhd/uhd_wbfm_receive.grc) it
apparently runs correctly but I get the following output:

linux; GNU C++ version 4.4.6 20110731 (Red Hat 4.4.6-3); Boost_104100;
UHD_003.004.000-1156d9b

-- Opening a USRP2/N-Series device...
--Current recv frame size: 1472 bytes
--Current send frame size: 1472 bytes

UHD Warning:
Unable to set the thread priority. Performance may be negatively affected.
Please see the general application notes in the manual for instructions.
EnvironmentError: OSError: error in pthread_setschedparam

UHD Warning:
The hardware does not support the requested RX frequency:
Target frequency: 106.900000 MHz
Actual frequency: 6.900000 MHz
gr_fir_ccc: using SSE
gr_fir_fff: using SSE
gr_fir_fcc: using SSE
aUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaU

Doesn't the Basic RX support 0MHz to 250MHz? Why can't I tune it
to FM broadcast frequencies in this example?
In my uhd_usrp_probe, I see something labeled RX DSP 0 and RX DSP 1
with a frequency range of -50.000 to 50.000 Mhz.
Am I somehow using that instead of my Basic RX daughterboard?
How do I specify exactly which daughterboard to use from within GRC?
Also, is the "aUaUaU..." output I see related to this problem? 'U' is
underflow right? what is 'a'?

I appreciate any help and advice you might have for me.

This is the result of uhd_usrp_probe:
_____________________________________________________
/
| Device: USRP2 / N-Series Device
| _____________________________________________________
| /
| | Mboard: USRP-N210-REV4
| | hardware: 2577
| | mac-addr: a0:36:fa:25:37:d8
| | ip-addr: 192.168.10.2
| | gpsdo: none
| | serial: EDR17S8UP
| |
| | Time sources: none, external, _external_, mimo
| | Clock sources: internal, external, mimo
| | Sensors: mimo_locked, ref_locked
| | _____________________________________________________
| | /
| | | RX DSP: 0
| | | Freq range: -50.000 to 50.000 Mhz
| | _____________________________________________________
| | /
| | | RX DSP: 1
| | | Freq range: -50.000 to 50.000 Mhz
| | _____________________________________________________
| | /
| | | RX Dboard: A
| | | ID: Basic RX (0x0001)
| | | _____________________________________________________
| | | /
| | | | 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
| | | _____________________________________________________
| | | /
| | | | RX Subdev: A
| | | | Name: Basic RX (0x0001) - A
| | | | Antennas:
| | | | Sensors:
| | | | Freq range: -250.000 to 250.000 Mhz
| | | | Gain Elements: None
| | | | Connection Type: I
| | | | Uses LO offset: No
| | | _____________________________________________________
| | | /
| | | | RX Subdev: B
| | | | Name: Basic RX (0x0001) - B
| | | | Antennas:
| | | | Sensors:
| | | | Freq range: -250.000 to 250.000 Mhz
| | | | Gain Elements: None
| | | | Connection Type: Q
| | | | Uses LO offset: No
| | | _____________________________________________________
| | | /
| | | | RX Codec: A
| | | | Name: ads62p44
| | | | Gain range digital: 0.0 to 6.0 step 0.5 dB
| | | | Gain range fine: 0.0 to 0.5 step 0.1 dB
| | _____________________________________________________
| | /
| | | TX DSP: 0
| | | Freq range: -250.000 to 250.000 Mhz
| | _____________________________________________________
| | /
| | | TX Dboard: A
| | | ID: Basic TX (0x0000)
| | | _____________________________________________________
| | | /
| | | | TX Subdev: AB
| | | | Name: Basic TX (0x0000) - AB
| | | | Antennas:
| | | | Sensors:
| | | | Freq range: -250.000 to 250.000 Mhz
| | | | Gain Elements: None
| | | | Connection Type: IQ
| | | | Uses LO offset: No
| | | _____________________________________________________
| | | /
| | | | TX Subdev: BA
| | | | Name: Basic TX (0x0000) - BA
| | | | Antennas:
| | | | Sensors:
| | | | Freq range: -250.000 to 250.000 Mhz
| | | | Gain Elements: None
| | | | Connection Type: QI
| | | | Uses LO offset: No
| | | _____________________________________________________
| | | /
| | | | TX Subdev: A
| | | | Name: Basic TX (0x0000) - A
| | | | Antennas:
| | | | Sensors:
| | | | Freq range: -250.000 to 250.000 Mhz
| | | | Gain Elements: None
| | | | Connection Type: I
| | | | Uses LO offset: No
| | | _____________________________________________________
| | | /
| | | | TX Subdev: B
| | | | Name: Basic TX (0x0000) - B
| | | | Antennas:
| | | | Sensors:
| | | | Freq range: -250.000 to 250.000 Mhz
| | | | Gain Elements: None
| | | | Connection Type: Q
| | | | Uses LO offset: No
| | | _____________________________________________________
| | | /
| | | | TX Codec: A
| | | | Name: ad9777
| | | | Gain Elements: None
John Malsbury
2012-03-27 17:25:52 UTC
Permalink
The warning is normal. Since there is no PLL/down-converter on the
BasicRX, the "valid range" within UHD is the first nyquist zone of the
USRPs ADC. The driver will handle the DSP setting to properly sample
the aliased signal. This warning is merely a notice that you are tuning
outside the first nyquist zone.

Have you tried to observe any signals with uhd_fft.py? Note that
without any front-end filtering, you will probably see many aliased signals.

-John
Post by S Corl
To Summarize: I'm trying to familiarize myself with the USRP N210, my
Basic TX and
Basic RX daughterboards and Gnu Radio.
My efforts to run an FM broadcast receiver as an example are failing
and I'm not sure why. I am able to run uhd_usrp_probe on my device. I
just can't seem to access the full range of frequencies I expect to
with Basic Rx.
When I try running the uhd_wbfm_receive.grc example
(gnuradio-3.5.1/gnuradio-examples/grc/uhd/uhd_wbfm_receive.grc) it
linux; GNU C++ version 4.4.6 20110731 (Red Hat 4.4.6-3); Boost_104100;
UHD_003.004.000-1156d9b
-- Opening a USRP2/N-Series device...
--Current recv frame size: 1472 bytes
--Current send frame size: 1472 bytes
Unable to set the thread priority. Performance may be negatively affected.
Please see the general application notes in the manual for instructions.
EnvironmentError: OSError: error in pthread_setschedparam
Target frequency: 106.900000 MHz
Actual frequency: 6.900000 MHz
gr_fir_ccc: using SSE
gr_fir_fff: using SSE
gr_fir_fcc: using SSE
aUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaU
Doesn't the Basic RX support 0MHz to 250MHz? Why can't I tune it
to FM broadcast frequencies in this example?
In my uhd_usrp_probe, I see something labeled RX DSP 0 and RX DSP 1
with a frequency range of -50.000 to 50.000 Mhz.
Am I somehow using that instead of my Basic RX daughterboard?
How do I specify exactly which daughterboard to use from within GRC?
Also, is the "aUaUaU..." output I see related to this problem? 'U' is
underflow right? what is 'a'?
I appreciate any help and advice you might have for me.
_____________________________________________________
/
| Device: USRP2 / N-Series Device
| _____________________________________________________
| /
| | Mboard: USRP-N210-REV4
| | hardware: 2577
| | mac-addr: a0:36:fa:25:37:d8
| | ip-addr: 192.168.10.2
| | gpsdo: none
| | serial: EDR17S8UP
| |
| | Time sources: none, external, _external_, mimo
| | Clock sources: internal, external, mimo
| | Sensors: mimo_locked, ref_locked
| | _____________________________________________________
| | /
| | | RX DSP: 0
| | | Freq range: -50.000 to 50.000 Mhz
| | _____________________________________________________
| | /
| | | RX DSP: 1
| | | Freq range: -50.000 to 50.000 Mhz
| | _____________________________________________________
| | /
| | | RX Dboard: A
| | | ID: Basic RX (0x0001)
| | | _____________________________________________________
| | | /
| | | | RX Subdev: AB
| | | | Name: Basic RX (0x0001) - AB
| | | | 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
| | | | Freq range: -250.000 to 250.000 Mhz
| | | | Gain Elements: None
| | | | Connection Type: QI
| | | | Uses LO offset: No
| | | _____________________________________________________
| | | /
| | | | RX Subdev: A
| | | | Name: Basic RX (0x0001) - A
| | | | Freq range: -250.000 to 250.000 Mhz
| | | | Gain Elements: None
| | | | Connection Type: I
| | | | Uses LO offset: No
| | | _____________________________________________________
| | | /
| | | | RX Subdev: B
| | | | Name: Basic RX (0x0001) - B
| | | | Freq range: -250.000 to 250.000 Mhz
| | | | Gain Elements: None
| | | | Connection Type: Q
| | | | Uses LO offset: No
| | | _____________________________________________________
| | | /
| | | | RX Codec: A
| | | | Name: ads62p44
| | | | Gain range digital: 0.0 to 6.0 step 0.5 dB
| | | | Gain range fine: 0.0 to 0.5 step 0.1 dB
| | _____________________________________________________
| | /
| | | TX DSP: 0
| | | Freq range: -250.000 to 250.000 Mhz
| | _____________________________________________________
| | /
| | | TX Dboard: A
| | | ID: Basic TX (0x0000)
| | | _____________________________________________________
| | | /
| | | | TX Subdev: AB
| | | | Name: Basic TX (0x0000) - AB
| | | | Freq range: -250.000 to 250.000 Mhz
| | | | Gain Elements: None
| | | | Connection Type: IQ
| | | | Uses LO offset: No
| | | _____________________________________________________
| | | /
| | | | TX Subdev: BA
| | | | Name: Basic TX (0x0000) - BA
| | | | Freq range: -250.000 to 250.000 Mhz
| | | | Gain Elements: None
| | | | Connection Type: QI
| | | | Uses LO offset: No
| | | _____________________________________________________
| | | /
| | | | TX Subdev: A
| | | | Name: Basic TX (0x0000) - A
| | | | Freq range: -250.000 to 250.000 Mhz
| | | | Gain Elements: None
| | | | Connection Type: I
| | | | Uses LO offset: No
| | | _____________________________________________________
| | | /
| | | | TX Subdev: B
| | | | Name: Basic TX (0x0000) - B
| | | | Freq range: -250.000 to 250.000 Mhz
| | | | Gain Elements: None
| | | | Connection Type: Q
| | | | Uses LO offset: No
| | | _____________________________________________________
| | | /
| | | | TX Codec: A
| | | | Name: ad9777
| | | | Gain Elements: None
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