Re: [Discuss-gnuradio] USRP2 FM TX and FM RX working together

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Re: [Discuss-gnuradio] USRP2 FM TX and FM RX working together

From:	Jorge Miguel
Subject:	Re: [Discuss-gnuradio] USRP2 FM TX and FM RX working together
Date:	Thu, 23 Sep 2010 09:36:24 +0200

Nick,

Now all my sample rates match. But I cannot demodulate the signal. However, I tune my FM phone receiver and the transmitted signal is ok. I can listen to it perfectly.

This is the message code I get on GRC:
..................SSSaUSSSSSSSaUSSSSSSSaUSSSSSSSSaUSSSSSSSaUSSSSSSSS
aUSSSSSSSaUSSSSSSSSaUSSSSSSSSaUSSSSSSSSaUSSSSSSSSSaUSSSSSSS
SaUSSSSSSSSSSaUSSSSSSSSSaUSSSSSSSaUSSSS............

Furthermore I found out that my Ethernet interface is discarding a lot of received packages (the ones that carry de demodulated signal to my computer). See:

~$ ifconfig
eth0      Link encap:Ethernet HWaddr 5c:ff:35:06:ad:06
          inet addr:10.0.0.87 Bcast:10.0.0.255 Mask:255.255.255.0
          inet6 addr: fe80::5eff:35ff:fe06:ad06/64 Scope:Link
          UP BROADCAST RUNNING PROMISC MULTICAST MTU:1500 Metric:1
          RX packets:29666606 errors:0 dropped:75746045 overruns:0 frame:0
          TX packets:4750896 errors:0 dropped:0 overruns:0 carrier:0
          collisions:26 txqueuelen:10
          RX bytes:3107428110 (3.1 GB) TX bytes:2389205908 (2.3 GB)
          Memory:f2600000-f2620000

But my interface is in 1000Mbps mode and full duplex.
Why do I have dis problem?

With my configuration I have 15,35Mbps to the USRP2 (Tx) and 3.2Mbps from the USRP2 (Rx). Is is by far less than the capacity of the Ethernet interface which is in this state:

~$ sudo ethtool eth0
Settings for eth0:
    Supported ports: [ TP ]
    Supported link modes:   10baseT/Half 10baseT/Full
                            100baseT/Half 100baseT/Full
                            1000baseT/Full
    Supports auto-negotiation: Yes
    Advertised link modes: 10baseT/Half 10baseT/Full
                            100baseT/Half 100baseT/Full
                            1000baseT/Full
    Advertised pause frame use: No
    Advertised auto-negotiation: Yes
    Link partner advertised link modes: Not reported
    Link partner advertised pause frame use: No
    Link partner advertised auto-negotiation: No
    Speed: 1000Mb/s
    Duplex: Full
    Port: Twisted Pair
    PHYAD: 1
    Transceiver: internal
    Auto-negotiation: on
    MDI-X: off
    Supports Wake-on: pumbag
    Wake-on: g
    Current message level: 0x00000001 (1)
    Link detected: yes

Modulator chain by itself works fine and do the demudulator chain does. But together I have this problem of Bandwidth?

Any ideas?

This is my new GRC code:

<?xml version='1.0' encoding='ASCII'?>
<flow_graph>
<timestamp>Thu Sep 23 09:18:32 2010</timestamp>
<block>
    <key>options</key>
    <param>
      <key>id</key>
      <value>top_block</value>
    </param>
    <param>
      <key>_enabled</key>
      <value>True</value>
    </param>
    <param>
      <key>title</key>
      <value></value>
    </param>
    <param>
      <key>author</key>
      <value></value>
    </param>
    <param>
      <key>description</key>
      <value></value>
    </param>
    <param>
      <key>window_size</key>
      <value>1280, 1024</value>
    </param>
    <param>
      <key>generate_options</key>
      <value>wx_gui</value>
    </param>
    <param>
      <key>category</key>
      <value>Custom</value>
    </param>
    <param>
      <key>run</key>
      <value>True</value>
    </param>
    <param>
      <key>realtime_scheduling</key>
      <value></value>
    </param>
    <param>
      <key>_coordinate</key>
      <value>(2, 384)</value>
    </param>
    <param>
      <key>_rotation</key>
      <value>0</value>
    </param>
</block>
<block>
    <key>note</key>
    <param>
      <key>id</key>
      <value>Chain1</value>
    </param>
    <param>
      <key>_enabled</key>
      <value>True</value>
    </param>
    <param>
      <key>note</key>
      <value>MODULATOR</value>
    </param>
    <param>
      <key>_coordinate</key>
      <value>(233, 9)</value>
    </param>
    <param>
      <key>_rotation</key>
      <value>0</value>
    </param>
</block>
<block>
    <key>variable_slider</key>
    <param>
      <key>id</key>
      <value>fm_freq_mod</value>
    </param>
    <param>
      <key>_enabled</key>
      <value>True</value>
    </param>
    <param>
      <key>label</key>
      <value>FM frequency modulator</value>
    </param>
    <param>
      <key>value</key>
      <value>94000000</value>
    </param>
    <param>
      <key>min</key>
      <value>0</value>
    </param>
    <param>
      <key>max</key>
      <value>110000000</value>
    </param>
    <param>
      <key>num_steps</key>
      <value>300</value>
    </param>
    <param>
      <key>style</key>
      <value>wx.SL_HORIZONTAL</value>
    </param>
    <param>
      <key>converver</key>
      <value>float_converter</value>
    </param>
    <param>
      <key>grid_pos</key>
      <value></value>
    </param>
    <param>
      <key>notebook</key>
      <value></value>
    </param>
    <param>
      <key>_coordinate</key>
      <value>(0, 253)</value>
    </param>
    <param>
      <key>_rotation</key>
      <value>0</value>
    </param>
</block>
<block>
    <key>variable_slider</key>
    <param>
      <key>id</key>
      <value>tune_filter</value>
    </param>
    <param>
      <key>_enabled</key>
      <value>True</value>
    </param>
    <param>
      <key>label</key>
      <value>LPF Cutoff Freq</value>
    </param>
    <param>
      <key>value</key>
      <value>75000</value>
    </param>
    <param>
      <key>min</key>
      <value>15000</value>
    </param>
    <param>
      <key>max</key>
      <value>150000</value>
    </param>
    <param>
      <key>num_steps</key>
      <value>1000</value>
    </param>
    <param>
      <key>style</key>
      <value>wx.SL_HORIZONTAL</value>
    </param>
    <param>
      <key>converver</key>
      <value>float_converter</value>
    </param>
    <param>
      <key>grid_pos</key>
      <value></value>
    </param>
    <param>
      <key>notebook</key>
      <value></value>
    </param>
    <param>
      <key>_coordinate</key>
      <value>(0, 127)</value>
    </param>
    <param>
      <key>_rotation</key>
      <value>0</value>
    </param>
</block>
<block>
    <key>variable_slider</key>
    <param>
      <key>id</key>
      <value>tune_osc_dem</value>
    </param>
    <param>
      <key>_enabled</key>
      <value>True</value>
    </param>
    <param>
      <key>label</key>
      <value>Tunned frequency demodulator</value>
    </param>
    <param>
      <key>value</key>
      <value>94000000</value>
    </param>
    <param>
      <key>min</key>
      <value>88000000</value>
    </param>
    <param>
      <key>max</key>
      <value>108000000</value>
    </param>
    <param>
      <key>num_steps</key>
      <value>800</value>
    </param>
    <param>
      <key>style</key>
      <value>wx.SL_HORIZONTAL</value>
    </param>
    <param>
      <key>converver</key>
      <value>float_converter</value>
    </param>
    <param>
      <key>grid_pos</key>
      <value></value>
    </param>
    <param>
      <key>notebook</key>
      <value></value>
    </param>
    <param>
      <key>_coordinate</key>
      <value>(1, 1)</value>
    </param>
    <param>
      <key>_rotation</key>
      <value>0</value>
    </param>
</block>
<block>
    <key>note</key>
    <param>
      <key>id</key>
      <value>Chain1_0</value>
    </param>
    <param>
      <key>_enabled</key>
      <value>True</value>
    </param>
    <param>
      <key>note</key>
      <value>DEMODULATOR</value>
    </param>
    <param>
      <key>_coordinate</key>
      <value>(361, 500)</value>
    </param>
    <param>
      <key>_rotation</key>
      <value>0</value>
    </param>
</block>
<block>
    <key>gr_frequency_modulator_fc</key>
    <param>
      <key>id</key>
      <value>gr_frequency_modulator_fc_0</value>
    </param>
    <param>
      <key>_enabled</key>
      <value>True</value>
    </param>
    <param>
      <key>sensitivity</key>
      <value>0.980</value>
    </param>
    <param>
      <key>_coordinate</key>
      <value>(596, 297)</value>
    </param>
    <param>
      <key>_rotation</key>
      <value>0</value>
    </param>
</block>
<block>
    <key>gr_multiply_const_vxx</key>
    <param>
      <key>id</key>
      <value>gr_multiply_const_vxx_1</value>
    </param>
    <param>
      <key>_enabled</key>
      <value>True</value>
    </param>
    <param>
      <key>type</key>
      <value>complex</value>
    </param>
    <param>
      <key>const</key>
      <value>32000</value>
    </param>
    <param>
      <key>vlen</key>
      <value>1</value>
    </param>
    <param>
      <key>_coordinate</key>
      <value>(797, 297)</value>
    </param>
    <param>
      <key>_rotation</key>
      <value>0</value>
    </param>
</block>
<block>
    <key>low_pass_filter</key>
    <param>
      <key>id</key>
      <value>low_pass_filter_0_0</value>
    </param>
    <param>
      <key>_enabled</key>
      <value>True</value>
    </param>
    <param>
      <key>type</key>
      <value>interp_fir_filter_fff</value>
    </param>
    <param>
      <key>decim</key>
      <value>1</value>
    </param>
    <param>
      <key>interp</key>
      <value>1</value>
    </param>
    <param>
      <key>gain</key>
      <value>1</value>
    </param>
    <param>
      <key>samp_rate</key>
      <value>240000</value>
    </param>
    <param>
      <key>cutoff_freq</key>
      <value>18e3</value>
    </param>
    <param>
      <key>width</key>
      <value>2e3</value>
    </param>
    <param>
      <key>window</key>
      <value>WIN_HAMMING</value>
    </param>
    <param>
      <key>beta</key>
      <value>6.76</value>
    </param>
    <param>
      <key>_coordinate</key>
      <value>(507, 44)</value>
    </param>
    <param>
      <key>_rotation</key>
      <value>0</value>
    </param>
</block>
<block>
    <key>usrp2_source_xxxx</key>
    <param>
      <key>id</key>
      <value>usrp2_source_xxxx_0</value>
    </param>
    <param>
      <key>_enabled</key>
      <value>True</value>
    </param>
    <param>
      <key>type</key>
      <value>complex</value>
    </param>
    <param>
      <key>interface</key>
      <value></value>
    </param>
    <param>
      <key>mac_addr</key>
      <value></value>
    </param>
    <param>
      <key>decimation</key>
      <value>500</value>
    </param>
    <param>
      <key>frequency</key>
      <value>tune_osc_dem</value>
    </param>
    <param>
      <key>lo_offset</key>
      <value>float('inf')</value>
    </param>
    <param>
      <key>gain</key>
      <value>20</value>
    </param>
    <param>
      <key>_coordinate</key>
      <value>(180, 583)</value>
    </param>
    <param>
      <key>_rotation</key>
      <value>0</value>
    </param>
</block>
<block>
    <key>blks2_rational_resampler_xxx</key>
    <param>
      <key>id</key>
      <value>blks2_rational_resampler_xxx_1_0_0</value>
    </param>
    <param>
      <key>_enabled</key>
      <value>True</value>
    </param>
    <param>
      <key>type</key>
      <value>ccc</value>
    </param>
    <param>
      <key>decim</key>
      <value>5</value>
    </param>
    <param>
      <key>interp</key>
      <value>6</value>
    </param>
    <param>
      <key>taps</key>
      <value>[]</value>
    </param>
    <param>
      <key>fractional_bw</key>
      <value>0</value>
    </param>
    <param>
      <key>_coordinate</key>
      <value>(391, 591)</value>
    </param>
    <param>
      <key>_rotation</key>
      <value>0</value>
    </param>
</block>
<block>
    <key>low_pass_filter</key>
    <param>
      <key>id</key>
      <value>low_pass_filter_0</value>
    </param>
    <param>
      <key>_enabled</key>
      <value>True</value>
    </param>
    <param>
      <key>type</key>
      <value>fir_filter_ccf</value>
    </param>
    <param>
      <key>decim</key>
      <value>1</value>
    </param>
    <param>
      <key>interp</key>
      <value>1</value>
    </param>
    <param>
      <key>gain</key>
      <value>20</value>
    </param>
    <param>
      <key>samp_rate</key>
      <value>240000</value>
    </param>
    <param>
      <key>cutoff_freq</key>
      <value>tune_filter</value>
    </param>
    <param>
      <key>width</key>
      <value>5000</value>
    </param>
    <param>
      <key>window</key>
      <value>WIN_HAMMING</value>
    </param>
    <param>
      <key>beta</key>
      <value>6.76</value>
    </param>
    <param>
      <key>_coordinate</key>
      <value>(613, 568)</value>
    </param>
    <param>
      <key>_rotation</key>
      <value>0</value>
    </param>
</block>
<block>
    <key>blks2_fm_demod_cf</key>
    <param>
      <key>id</key>
      <value>blks2_fm_demod_cf_0</value>
    </param>
    <param>
      <key>_enabled</key>
      <value>True</value>
    </param>
    <param>
      <key>chan_rate</key>
      <value>240000</value>
    </param>
    <param>
      <key>audio_decim</key>
      <value>5</value>
    </param>
    <param>
      <key>deviation</key>
      <value>75000</value>
    </param>
    <param>
      <key>audio_pass</key>
      <value>1000</value>
    </param>
    <param>
      <key>audio_stop</key>
      <value>16000</value>
    </param>
    <param>
      <key>gain</key>
      <value>20.0</value>
    </param>
    <param>
      <key>tau</key>
      <value>75e-6</value>
    </param>
    <param>
      <key>_coordinate</key>
      <value>(867, 417)</value>
    </param>
    <param>
      <key>_rotation</key>
      <value>0</value>
    </param>
</block>
<block>
    <key>audio_sink</key>
    <param>
      <key>id</key>
      <value>audio_sink_0</value>
    </param>
    <param>
      <key>_enabled</key>
      <value>True</value>
    </param>
    <param>
      <key>samp_rate</key>
      <value>48000</value>
    </param>
    <param>
      <key>device_name</key>
      <value>plughw:0,0</value>
    </param>
    <param>
      <key>ok_to_block</key>
      <value>False</value>
    </param>
    <param>
      <key>num_inputs</key>
      <value>1</value>
    </param>
    <param>
      <key>_coordinate</key>
      <value>(945, 654)</value>
    </param>
    <param>
      <key>_rotation</key>
      <value>0</value>
    </param>
</block>
<block>
    <key>gr_wavfile_source</key>
    <param>
      <key>id</key>
      <value>gr_wavfile_source_0</value>
    </param>
    <param>
      <key>_enabled</key>
      <value>True</value>
    </param>
    <param>
      <key>file</key>
      <value>/home/thales/Desktop/outfile2.wav</value>
    </param>
    <param>
      <key>repeat</key>
      <value>True</value>
    </param>
    <param>
      <key>nchan</key>
      <value>1</value>
    </param>
    <param>
      <key>_coordinate</key>
      <value>(195, 196)</value>
    </param>
    <param>
      <key>_rotation</key>
      <value>0</value>
    </param>
</block>
<block>
    <key>blks2_rational_resampler_xxx</key>
    <param>
      <key>id</key>
      <value>blks2_rational_resampler_xxx_0_0</value>
    </param>
    <param>
      <key>_enabled</key>
      <value>True</value>
    </param>
    <param>
      <key>type</key>
      <value>fff</value>
    </param>
    <param>
      <key>decim</key>
      <value>1</value>
    </param>
    <param>
      <key>interp</key>
      <value>5</value>
    </param>
    <param>
      <key>taps</key>
      <value>[]</value>
    </param>
    <param>
      <key>fractional_bw</key>
      <value>0</value>
    </param>
    <param>
      <key>_coordinate</key>
      <value>(280, 68)</value>
    </param>
    <param>
      <key>_rotation</key>
      <value>0</value>
    </param>
</block>
<block>
    <key>usrp2_sink_xxxx</key>
    <param>
      <key>id</key>
      <value>usrp2_sink_xxxx_0</value>
    </param>
    <param>
      <key>_enabled</key>
      <value>True</value>
    </param>
    <param>
      <key>type</key>
      <value>complex</value>
    </param>
    <param>
      <key>interface</key>
      <value></value>
    </param>
    <param>
      <key>mac_addr</key>
      <value></value>
    </param>
    <param>
      <key>interpolation</key>
      <value>104</value>
    </param>
    <param>
      <key>frequency</key>
      <value>fm_freq_mod</value>
    </param>
    <param>
      <key>lo_offset</key>
      <value>float('inf')</value>
    </param>
    <param>
      <key>gain</key>
      <value>0</value>
    </param>
    <param>
      <key>_coordinate</key>
      <value>(1011, 265)</value>
    </param>
    <param>
      <key>_rotation</key>
      <value>0</value>
    </param>
</block>
<block>
    <key>blks2_rational_resampler_xxx</key>
    <param>
      <key>id</key>
      <value>blks2_rational_resampler_xxx_1</value>
    </param>
    <param>
      <key>_enabled</key>
      <value>True</value>
    </param>
    <param>
      <key>type</key>
      <value>fff</value>
    </param>
    <param>
      <key>decim</key>
      <value>1</value>
    </param>
    <param>
      <key>interp</key>
      <value>4</value>
    </param>
    <param>
      <key>taps</key>
      <value>[]</value>
    </param>
    <param>
      <key>fractional_bw</key>
      <value>0</value>
    </param>
    <param>
      <key>_coordinate</key>
      <value>(756, 68)</value>
    </param>
    <param>
      <key>_rotation</key>
      <value>0</value>
    </param>
</block>
<connection>
    <source_block_id>blks2_rational_resampler_xxx_1</source_block_id>
    <sink_block_id>gr_frequency_modulator_fc_0</sink_block_id>
    <source_key>0</source_key>
    <sink_key>0</sink_key>
</connection>
<connection>
    <source_block_id>gr_multiply_const_vxx_1</source_block_id>
    <sink_block_id>usrp2_sink_xxxx_0</sink_block_id>
    <source_key>0</source_key>
    <sink_key>0</sink_key>
</connection>
<connection>
    <source_block_id>gr_frequency_modulator_fc_0</source_block_id>
    <sink_block_id>gr_multiply_const_vxx_1</sink_block_id>
    <source_key>0</source_key>
    <sink_key>0</sink_key>
</connection>
<connection>
    <source_block_id>blks2_rational_resampler_xxx_0_0</source_block_id>
    <sink_block_id>low_pass_filter_0_0</sink_block_id>
    <source_key>0</source_key>
    <sink_key>0</sink_key>
</connection>
<connection>
    <source_block_id>low_pass_filter_0_0</source_block_id>
    <sink_block_id>blks2_rational_resampler_xxx_1</sink_block_id>
    <source_key>0</source_key>
    <sink_key>0</sink_key>
</connection>
<connection>
    <source_block_id>gr_wavfile_source_0</source_block_id>
    <sink_block_id>blks2_rational_resampler_xxx_0_0</sink_block_id>
    <source_key>0</source_key>
    <sink_key>0</sink_key>
</connection>
<connection>
    <source_block_id>blks2_fm_demod_cf_0</source_block_id>
    <sink_block_id>audio_sink_0</sink_block_id>
    <source_key>0</source_key>
    <sink_key>0</sink_key>
</connection>
<connection>
    <source_block_id>low_pass_filter_0</source_block_id>
    <sink_block_id>blks2_fm_demod_cf_0</sink_block_id>
    <source_key>0</source_key>
    <sink_key>0</sink_key>
</connection>
<connection>
    <source_block_id>blks2_rational_resampler_xxx_1_0_0</source_block_id>
    <sink_block_id>low_pass_filter_0</sink_block_id>
    <source_key>0</source_key>
    <sink_key>0</sink_key>
</connection>
<connection>
    <source_block_id>usrp2_source_xxxx_0</source_block_id>
    <sink_block_id>blks2_rational_resampler_xxx_1_0_0</sink_block_id>
    <source_key>0</source_key>
    <sink_key>0</sink_key>
</connection>
</flow_graph>

On 22 September 2010 19:39, Nick Foster <address@hidden> wrote:
>
> Jorge,
>
> Your sample rates do not match. The sample rates your USRP2 is operating
> at is fixed for a given decimation/interpolation, and you must choose
> sample rates in your upstream and downstream blocks to match.
>
> For instance, in your receiver chain, you are using a decimation rate of
> 64. This means that your USRP2 will provide samples to the rest of your
> flowgraph at 1.5625Msps. This is connected to an FFT sink operating at
> 200ksps -- this is not correct. If you want to operate at 200ksps you
> must provide a resampling block to get there. Likewise, your rational
> resampler at (32/25) outputs a sample rate of (1.5625e6 * (32/25)) = 2e6
> samples per second. Your low pass filter which follows is expecting a
> sample rate of 256k. This will cause the filter coefficients to be
> incorrectly calculated, and eventually will cause over/underruns when
> you finally get to a block which operates at a fixed sample rate, like
> your audio sink.
>
> The "SSSSSSSSSSSS" you are seeing is caused by the audio sink being
> overrun by providing it with 250ksps when it is expecting 32ksps.
>
> Nick
>
> On Wed, 2010-09-22 at 08:30 +0200, Jorge Miguel wrote:
> > Sorry, in my previous email the code was corrupted.. This is the right
> > code of my GRC:
> >
> > <?xml version='1.0' encoding='ASCII'?>
> > <flow_graph>
> > <timestamp>Wed Sep 22 08:14:26 2010</timestamp>
> > <block>
> > <key>variable_slider</key>
> > <param>
> > <key>id</key>
> > <value>tune_filter</value>
> > </param>
> > <param>
> > <key>_enabled</key>
> > <value>True</value>
> > </param>
> > <param>
> > <key>label</key>
> > <value>LPF Cutoff Freq</value>
> > </param>
> > <param>
> > <key>value</key>
> > <value>75000</value>
> > </param>
> > <param>
> > <key>min</key>
> > <value>15000</value>
> > </param>
> > <param>
> > <key>max</key>
> > <value>150000</value>
> > </param>
> > <param>
> > <key>num_steps</key>
> > <value>1000</value>
> > </param>
> > <param>
> > <key>style</key>
> > <value>wx.SL_HORIZONTAL</value>
> > </param>
> > <param>
> > <key>converver</key>
> > <value>float_converter</value>
> > </param>
> > <param>
> > <key>grid_pos</key>
> > <value></value>
> > </param>
> > <param>
> > <key>notebook</key>
> > <value></value>
> > </param>
> > <param>
> > <key>_coordinate</key>
> > <value>(0, 127)</value>
> > </param>
> > <param>
> > <key>_rotation</key>
> > <value>0</value>
> > </param>
> > </block>
> > <block>
> > <key>gr_frequency_modulator_fc</key>
> > <param>
> > <key>id</key>
> > <value>gr_frequency_modulator_fc_0</value>
> > </param>
> > <param>
> > <key>_enabled</key>
> > <value>True</value>
> > </param>
> > <param>
> > <key>sensitivity</key>
> > <value>0.980</value>
> > </param>
> > <param>
> > <key>_coordinate</key>
> > <value>(454, 315)</value>
> > </param>
> > <param>
> > <key>_rotation</key>
> > <value>0</value>
> > </param>
> > </block>
> > <block>
> > <key>blks2_rational_resampler_xxx</key>
> > <param>
> > <key>id</key>
> > <value>blks2_rational_resampler_xxx_0_0</value>
> > </param>
> > <param>
> > <key>_enabled</key>
> > <value>True</value>
> > </param>
> > <param>
> > <key>type</key>
> > <value>fff</value>
> > </param>
> > <param>
> > <key>decim</key>
> > <value>1</value>
> > </param>
> > <param>
> > <key>interp</key>
> > <value>5</value>
> > </param>
> > <param>
> > <key>taps</key>
> > <value>[]</value>
> > </param>
> > <param>
> > <key>fractional_bw</key>
> > <value>0</value>
> > </param>
> > <param>
> > <key>_coordinate</key>
> > <value>(233, 68)</value>
> > </param>
> > <param>
> > <key>_rotation</key>
> > <value>0</value>
> > </param>
> > </block>
> > <block>
> > <key>note</key>
> > <param>
> > <key>id</key>
> > <value>Chain1</value>
> > </param>
> > <param>
> > <key>_enabled</key>
> > <value>True</value>
> > </param>
> > <param>
> > <key>note</key>
> > <value>MODULATOR</value>
> > </param>
> > <param>
> > <key>_coordinate</key>
> > <value>(233, 9)</value>
> > </param>
> > <param>
> > <key>_rotation</key>
> > <value>0</value>
> > </param>
> > </block>
> > <block>
> > <key>note</key>
> > <param>
> > <key>id</key>
> > <value>Chain1_0</value>
> > </param>
> > <param>
> > <key>_enabled</key>
> > <value>True</value>
> > </param>
> > <param>
> > <key>note</key>
> > <value>DEMODULATOR</value>
> > </param>
> > <param>
> > <key>_coordinate</key>
> > <value>(181, 427)</value>
> > </param>
> > <param>
> > <key>_rotation</key>
> > <value>0</value>
> > </param>
> > </block>
> > <block>
> > <key>blks2_rational_resampler_xxx</key>
> > <param>
> > <key>id</key>
> > <value>blks2_rational_resampler_xxx_1</value>
> > </param>
> > <param>
> > <key>_enabled</key>
> > <value>True</value>
> > </param>
> > <param>
> > <key>type</key>
> > <value>fff</value>
> > </param>
> > <param>
> > <key>decim</key>
> > <value>1</value>
> > </param>
> > <param>
> > <key>interp</key>
> > <value>4</value>
> > </param>
> > <param>
> > <key>taps</key>
> > <value>[]</value>
> > </param>
> > <param>
> > <key>fractional_bw</key>
> > <value>0</value>
> > </param>
> > <param>
> > <key>_coordinate</key>
> > <value>(699, 122)</value>
> > </param>
> > <param>
> > <key>_rotation</key>
> > <value>0</value>
> > </param>
> > </block>
> > <block>
> > <key>wxgui_fftsink2</key>
> > <param>
> > <key>id</key>
> > <value>wxgui_fftsink2_0_0</value>
> > </param>
> > <param>
> > <key>_enabled</key>
> > <value>True</value>
> > </param>
> > <param>
> > <key>type</key>
> > <value>complex</value>
> > </param>
> > <param>
> > <key>title</key>
> > <value>FFT Plot</value>
> > </param>
> > <param>
> > <key>samp_rate</key>
> > <value>200000</value>
> > </param>
> > <param>
> > <key>baseband_freq</key>
> > <value>2000000</value>
> > </param>
> > <param>
> > <key>y_per_div</key>
> > <value>10</value>
> > </param>
> > <param>
> > <key>y_divs</key>
> > <value>10</value>
> > </param>
> > <param>
> > <key>ref_level</key>
> > <value>50</value>
> > </param>
> > <param>
> > <key>fft_size</key>
> > <value>512</value>
> > </param>
> > <param>
> > <key>fft_rate</key>
> > <value>50</value>
> > </param>
> > <param>
> > <key>peak_hold</key>
> > <value>False</value>
> > </param>
> > <param>
> > <key>average</key>
> > <value>False</value>
> > </param>
> > <param>
> > <key>avg_alpha</key>
> > <value>0</value>
> > </param>
> > <param>
> > <key>grid_pos</key>
> > <value></value>
> > </param>
> > <param>
> > <key>notebook</key>
> > <value></value>
> > </param>
> > <param>
> > <key>_coordinate</key>
> > <value>(370, 568)</value>
> > </param>
> > <param>
> > <key>_rotation</key>
> > <value>0</value>
> > </param>
> > </block>
> > <block>
> > <key>audio_sink</key>
> > <param>
> > <key>id</key>
> > <value>audio_sink_0</value>
> > </param>
> > <param>
> > <key>_enabled</key>
> > <value>True</value>
> > </param>
> > <param>
> > <key>samp_rate</key>
> > <value>32000</value>
> > </param>
> > <param>
> > <key>device_name</key>
> > <value>plughw:0,0</value>
> > </param>
> > <param>
> > <key>ok_to_block</key>
> > <value>True</value>
> > </param>
> > <param>
> > <key>num_inputs</key>
> > <value>1</value>
> > </param>
> > <param>
> > <key>_coordinate</key>
> > <value>(607, 648)</value>
> > </param>
> > <param>
> > <key>_rotation</key>
> > <value>0</value>
> > </param>
> > </block>
> > <block>
> > <key>usrp2_sink_xxxx</key>
> > <param>
> > <key>id</key>
> > <value>usrp2_sink_xxxx_0</value>
> > </param>
> > <param>
> > <key>_enabled</key>
> > <value>True</value>
> > </param>
> > <param>
> > <key>type</key>
> > <value>complex</value>
> > </param>
> > <param>
> > <key>interface</key>
> > <value></value>
> > </param>
> > <param>
> > <key>mac_addr</key>
> > <value></value>
> > </param>
> > <param>
> > <key>interpolation</key>
> > <value>104</value>
> > </param>
> > <param>
> > <key>frequency</key>
> > <value>fm_freq_mod</value>
> > </param>
> > <param>
> > <key>lo_offset</key>
> > <value>float('inf')</value>
> > </param>
> > <param>
> > <key>gain</key>
> > <value>0</value>
> > </param>
> > <param>
> > <key>_coordinate</key>
> > <value>(874, 283)</value>
> > </param>
> > <param>
> > <key>_rotation</key>
> > <value>0</value>
> > </param>
> > </block>
> > <block>
> > <key>usrp2_source_xxxx</key>
> > <param>
> > <key>id</key>
> > <value>usrp2_source_xxxx_0</value>
> > </param>
> > <param>
> > <key>_enabled</key>
> > <value>True</value>
> > </param>
> > <param>
> > <key>type</key>
> > <value>complex</value>
> > </param>
> > <param>
> > <key>interface</key>
> > <value></value>
> > </param>
> > <param>
> > <key>mac_addr</key>
> > <value></value>
> > </param>
> > <param>
> > <key>decimation</key>
> > <value>64</value>
> > </param>
> > <param>
> > <key>frequency</key>
> > <value>tune_osc_dem</value>
> > </param>
> > <param>
> > <key>lo_offset</key>
> > <value>float('inf')</value>
> > </param>
> > <param>
> > <key>gain</key>
> > <value>20</value>
> > </param>
> > <param>
> > <key>_coordinate</key>
> > <value>(162, 521)</value>
> > </param>
> > <param>
> > <key>_rotation</key>
> > <value>0</value>
> > </param>
> > </block>
> > <block>
> > <key>variable_slider</key>
> > <param>
> > <key>id</key>
> > <value>fm_freq_mod</value>
> > </param>
> > <param>
> > <key>_enabled</key>
> > <value>True</value>
> > </param>
> > <param>
> > <key>label</key>
> > <value>FM frequency modulator</value>
> > </param>
> > <param>
> > <key>value</key>
> > <value>94000000</value>
> > </param>
> > <param>
> > <key>min</key>
> > <value>0</value>
> > </param>
> > <param>
> > <key>max</key>
> > <value>110000000</value>
> > </param>
> > <param>
> > <key>num_steps</key>
> > <value>300</value>
> > </param>
> > <param>
> > <key>style</key>
> > <value>wx.SL_HORIZONTAL</value>
> > </param>
> > <param>
> > <key>converver</key>
> > <value>float_converter</value>
> > </param>
> > <param>
> > <key>grid_pos</key>
> > <value></value>
> > </param>
> > <param>
> > <key>notebook</key>
> > <value></value>
> > </param>
> > <param>
> > <key>_coordinate</key>
> > <value>(0, 253)</value>
> > </param>
> > <param>
> > <key>_rotation</key>
> > <value>0</value>
> > </param>
> > </block>
> > <block>
> > <key>variable_slider</key>
> > <param>
> > <key>id</key>
> > <value>tune_osc_dem</value>
> > </param>
> > <param>
> > <key>_enabled</key>
> > <value>True</value>
> > </param>
> > <param>
> > <key>label</key>
> > <value>Tunned frequency demodulator</value>
> > </param>
> > <param>
> > <key>value</key>
> > <value>94000000</value>
> > </param>
> > <param>
> > <key>min</key>
> > <value>88000000</value>
> > </param>
> > <param>
> > <key>max</key>
> > <value>108000000</value>
> > </param>
> > <param>
> > <key>num_steps</key>
> > <value>800</value>
> > </param>
> > <param>
> > <key>style</key>
> > <value>wx.SL_HORIZONTAL</value>
> > </param>
> > <param>
> > <key>converver</key>
> > <value>float_converter</value>
> > </param>
> > <param>
> > <key>grid_pos</key>
> > <value></value>
> > </param>
> > <param>
> > <key>notebook</key>
> > <value></value>
> > </param>
> > <param>
> > <key>_coordinate</key>
> > <value>(1, 1)</value>
> > </param>
> > <param>
> > <key>_rotation</key>
> > <value>0</value>
> > </param>
> > </block>
> > <block>
> > <key>gr_wavfile_source</key>
> > <param>
> > <key>id</key>
> > <value>gr_wavfile_source_0</value>
> > </param>
> > <param>
> > <key>_enabled</key>
> > <value>True</value>
> > </param>
> > <param>
> > <key>file</key>
> > <value>/home/thales/Desktop/outfile2.wav</value>
> > </param>
> > <param>
> > <key>repeat</key>
> > <value>True</value>
> > </param>
> > <param>
> > <key>nchan</key>
> > <value>1</value>
> > </param>
> > <param>
> > <key>_coordinate</key>
> > <value>(223, 186)</value>
> > </param>
> > <param>
> > <key>_rotation</key>
> > <value>180</value>
> > </param>
> > </block>
> > <block>
> > <key>gr_multiply_const_vxx</key>
> > <param>
> > <key>id</key>
> > <value>gr_multiply_const_vxx_1</value>
> > </param>
> > <param>
> > <key>_enabled</key>
> > <value>True</value>
> > </param>
> > <param>
> > <key>type</key>
> > <value>complex</value>
> > </param>
> > <param>
> > <key>const</key>
> > <value>32000</value>
> > </param>
> > <param>
> > <key>vlen</key>
> > <value>1</value>
> > </param>
> > <param>
> > <key>_coordinate</key>
> > <value>(645, 315)</value>
> > </param>
> > <param>
> > <key>_rotation</key>
> > <value>0</value>
> > </param>
> > </block>
> > <block>
> > <key>blks2_rational_resampler_xxx</key>
> > <param>
> > <key>id</key>
> > <value>blks2_rational_resampler_xxx_1_0_0</value>
> > </param>
> > <param>
> > <key>_enabled</key>
> > <value>True</value>
> > </param>
> > <param>
> > <key>type</key>
> > <value>ccc</value>
> > </param>
> > <param>
> > <key>decim</key>
> > <value>25</value>
> > </param>
> > <param>
> > <key>interp</key>
> > <value>32</value>
> > </param>
> > <param>
> > <key>taps</key>
> > <value>[]</value>
> > </param>
> > <param>
> > <key>fractional_bw</key>
> > <value>0</value>
> > </param>
> > <param>
> > <key>_coordinate</key>
> > <value>(371, 467)</value>
> > </param>
> > <param>
> > <key>_rotation</key>
> > <value>0</value>
> > </param>
> > </block>
> > <block>
> > <key>low_pass_filter</key>
> > <param>
> > <key>id</key>
> > <value>low_pass_filter_0</value>
> > </param>
> > <param>
> > <key>_enabled</key>
> > <value>True</value>
> > </param>
> > <param>
> > <key>type</key>
> > <value>fir_filter_ccf</value>
> > </param>
> > <param>
> > <key>decim</key>
> > <value>2</value>
> > </param>
> > <param>
> > <key>interp</key>
> > <value>1</value>
> > </param>
> > <param>
> > <key>gain</key>
> > <value>10</value>
> > </param>
> > <param>
> > <key>samp_rate</key>
> > <value>256000</value>
> > </param>
> > <param>
> > <key>cutoff_freq</key>
> > <value>tune_filter</value>
> > </param>
> > <param>
> > <key>width</key>
> > <value>5000</value>
> > </param>
> > <param>
> > <key>window</key>
> > <value>WIN_HAMMING</value>
> > </param>
> > <param>
> > <key>beta</key>
> > <value>6.76</value>
> > </param>
> > <param>
> > <key>_coordinate</key>
> > <value>(583, 443)</value>
> > </param>
> > <param>
> > <key>_rotation</key>
> > <value>0</value>
> > </param>
> > </block>
> > <block>
> > <key>blks2_fm_demod_cf</key>
> > <param>
> > <key>id</key>
> > <value>blks2_fm_demod_cf_0</value>
> > </param>
> > <param>
> > <key>_enabled</key>
> > <value>True</value>
> > </param>
> > <param>
> > <key>chan_rate</key>
> > <value>128000</value>
> > </param>
> > <param>
> > <key>audio_decim</key>
> > <value>4</value>
> > </param>
> > <param>
> > <key>deviation</key>
> > <value>75000</value>
> > </param>
> > <param>
> > <key>audio_pass</key>
> > <value>1000</value>
> > </param>
> > <param>
> > <key>audio_stop</key>
> > <value>16000</value>
> > </param>
> > <param>
> > <key>gain</key>
> > <value>20.0</value>
> > </param>
> > <param>
> > <key>tau</key>
> > <value>75e-6</value>
> > </param>
> > <param>
> > <key>_coordinate</key>
> > <value>(784, 443)</value>
> > </param>
> > <param>
> > <key>_rotation</key>
> > <value>0</value>
> > </param>
> > </block>
> > <block>
> > <key>low_pass_filter</key>
> > <param>
> > <key>id</key>
> > <value>low_pass_filter_0_0</value>
> > </param>
> > <param>
> > <key>_enabled</key>
> > <value>True</value>
> > </param>
> > <param>
> > <key>type</key>
> > <value>interp_fir_filter_fff</value>
> > </param>
> > <param>
> > <key>decim</key>
> > <value>1</value>
> > </param>
> > <param>
> > <key>interp</key>
> > <value>1</value>
> > </param>
> > <param>
> > <key>gain</key>
> > <value>1</value>
> > </param>
> > <param>
> > <key>samp_rate</key>
> > <value>160000</value>
> > </param>
> > <param>
> > <key>cutoff_freq</key>
> > <value>1.5e3</value>
> > </param>
> > <param>
> > <key>width</key>
> > <value>2e3</value>
> > </param>
> > <param>
> > <key>window</key>
> > <value>WIN_HAMMING</value>
> > </param>
> > <param>
> > <key>beta</key>
> > <value>6.76</value>
> > </param>
> > <param>
> > <key>_coordinate</key>
> > <value>(458, 44)</value>
> > </param>
> > <param>
> > <key>_rotation</key>
> > <value>0</value>
> > </param>
> > </block>
> > <block>
> > <key>options</key>
> > <param>
> > <key>id</key>
> > <value>top_block</value>
> > </param>
> > <param>
> > <key>_enabled</key>
> > <value>True</value>
> > </param>
> > <param>
> > <key>title</key>
> > <value></value>
> > </param>
> > <param>
> > <key>author</key>
> > <value></value>
> > </param>
> > <param>
> > <key>description</key>
> > <value></value>
> > </param>
> > <param>
> > <key>window_size</key>
> > <value>1280, 1024</value>
> > </param>
> > <param>
> > <key>generate_options</key>
> > <value>wx_gui</value>
> > </param>
> > <param>
> > <key>category</key>
> > <value>Custom</value>
> > </param>
> > <param>
> > <key>run</key>
> > <value>True</value>
> > </param>
> > <param>
> > <key>realtime_scheduling</key>
> > <value></value>
> > </param>
> > <param>
> > <key>_coordinate</key>
> > <value>(2, 384)</value>
> > </param>
> > <param>
> > <key>_rotation</key>
> > <value>0</value>
> > </param>
> > </block>
> > <connection>
> > <source_block_id>low_pass_filter_0_0</source_block_id>
> > <sink_block_id>blks2_rational_resampler_xxx_1</sink_block_id>
> > <source_key>0</source_key>
> > <sink_key>0</sink_key>
> > </connection>
> > <connection>
> >
> > <source_block_id>blks2_rational_resampler_xxx_0_0</source_block_id>
> > <sink_block_id>low_pass_filter_0_0</sink_block_id>
> > <source_key>0</source_key>
> > <sink_key>0</sink_key>
> > </connection>
> > <connection>
> > <source_block_id>blks2_rational_resampler_xxx_1</source_block_id>
> > <sink_block_id>gr_frequency_modulator_fc_0</sink_block_id>
> > <source_key>0</source_key>
> > <sink_key>0</sink_key>
> > </connection>
> > <connection>
> > <source_block_id>gr_frequency_modulator_fc_0</source_block_id>
> > <sink_block_id>gr_multiply_const_vxx_1</sink_block_id>
> > <source_key>0</source_key>
> > <sink_key>0</sink_key>
> > </connection>
> > <connection>
> > <source_block_id>gr_multiply_const_vxx_1</source_block_id>
> > <sink_block_id>usrp2_sink_xxxx_0</sink_block_id>
> > <source_key>0</source_key>
> > <sink_key>0</sink_key>
> > </connection>
> > <connection>
> > <source_block_id>gr_wavfile_source_0</source_block_id>
> > <sink_block_id>blks2_rational_resampler_xxx_0_0</sink_block_id>
> > <source_key>0</source_key>
> > <sink_key>0</sink_key>
> > </connection>
> > <connection>
> > <source_block_id>usrp2_source_xxxx_0</source_block_id>
> > <sink_block_id>blks2_rational_resampler_xxx_1_0_0</sink_block_id>
> > <source_key>0</source_key>
> > <sink_key>0</sink_key>
> > </connection>
> > <connection>
> > <source_block_id>usrp2_source_xxxx_0</source_block_id>
> > <sink_block_id>wxgui_fftsink2_0_0</sink_block_id>
> > <source_key>0</source_key>
> > <sink_key>0</sink_key>
> > </connection>
> > <connection>
> > <source_block_id>blks2_fm_demod_cf_0</source_block_id>
> > <sink_block_id>audio_sink_0</sink_block_id>
> > <source_key>0</source_key>
> > <sink_key>0</sink_key>
> > </connection>
> > <connection>
> >
> > <source_block_id>blks2_rational_resampler_xxx_1_0_0</source_block_id>
> > <sink_block_id>low_pass_filter_0</sink_block_id>
> > <source_key>0</source_key>
> > <sink_key>0</sink_key>
> > </connection>
> > <connection>
> > <source_block_id>low_pass_filter_0</source_block_id>
> > <sink_block_id>blks2_fm_demod_cf_0</sink_block_id>
> > <source_key>0</source_key>
> > <sink_key>0</sink_key>
> > </connection>
> > </flow_graph>
> >
> > On 21 September 2010 18:59, Rafael Diniz <address@hidden> wrote:
> > Hi Jorge,
> > Can you copy the .grc file you created?
> >
> >
> > > Hello community!
> > >
> > > I initiated myself in GNU radio two weeks ago and I am
> > learning as fast as
> > > I
> > > can. To begin with, I decided to play with GRC and my URSP2.
> > > I successfully built a FM modulator that works fine.
> > > I successfully built a FM demodulator that works fine.
> > > But there are still several things I do not understand.
> > >
> > > While building the FM modulator:
> > > 1)Wave file source
> > > 2)Rational resampler
> > > 3)LPF
> > > 4)Rational resampler
> > > 5)Frequency Mod
> > > 6)Multiply const
> > > 7)USRP2 sink
> > >
> > > Why is block 6 necessary? I tried with lots of values over 2
> > and all of
> > > them
> > > are ok. I realized that the smaller the number, the higher
> > the noise in my
> > > receiver (my mobile phone). Is it related to the amplitude
> > of the
> > > modulated
> > > signal?
> > >
> > > Another thing very strange is that if I create a GRC file
> > with both,
> > > transmitter and receiver with exactly the same blocks and
> > the same
> > > parameters I cannot hear any demodulated signal. I can see
> > information
> > > with
> > > a FFT block connected to the receiver chain, and I am able
> > to demodulate
> > > the
> > > signal with my mobile phone when the example is running but
> > in my computer
> > > I
> > > do not hear anything else besides noise mixed with some sort
> > of
> > > non-understandable signal. Thus, I guess I have to change
> > something in the
> > > receiver chain although it works alone in my FM demodulator.
> > I changed
> > > every
> > > single parameter but I cannot get any improvement.
> > >
> > > Any suggestions?
> > >
> > > Many thanks in advance,
> > > Jorge.
> >
> >
> >
> >
> > _______________________________________________
> > Discuss-gnuradio mailing list
> > address@hidden
> > http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
>
>

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[Discuss-gnuradio] USRP2 FM TX and FM RX working together, Jorge Miguel, 2010/09/21
- Re: [Discuss-gnuradio] USRP2 FM TX and FM RX working together, Rafael Diniz, 2010/09/21
  - Re: [Discuss-gnuradio] USRP2 FM TX and FM RX working together, Jorge Miguel, 2010/09/22
  - Re: [Discuss-gnuradio] USRP2 FM TX and FM RX working together, Jorge Miguel, 2010/09/22
    - Re: [Discuss-gnuradio] USRP2 FM TX and FM RX working together, Nick Foster, 2010/09/22
    - Re: [Discuss-gnuradio] USRP2 FM TX and FM RX working together, Jorge Miguel <=
    - Re: [Discuss-gnuradio] USRP2 FM TX and FM RX working together, Josh Blum, 2010/09/23
  - Re: [Discuss-gnuradio] USRP2 FM TX and FM RX working together, Jorge Miguel, 2010/09/22
    - [Discuss-gnuradio] Re: USRP2 FM TX and FM RX working together, Patrick Strasser, 2010/09/24

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