"check topology failed"

Can anyone please tell me that why I am getting the following message
when running tx_voice.py:

gr_fir_fff: using SSE
Warning: failed to enable realtime scheduling
audio_alsa_source[hw:0,0]: set_channels failed: Invalid argument
terminate called after throwing an instance of ‘std::runtime_error’
what(): check topology failed on audio_alsa_source(11) using
ninputs=0, noutputs=1
Aborted (core dumped)

Thankyou


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On 2/9/08, [email protected] [email protected] wrote:

Can anyone please tell me that why I am getting the following message when running tx_voice.py:

Please post your entire command line.

audio_alsa_source[hw:0,0]: set_channels failed: Invalid argument
terminate called after throwing an instance of ‘std::runtime_error’
what(): check topology failed on audio_alsa_source(11) using ninputs=0, noutputs=1

This is a problem with what the ALSA driver thinks its hardware source
is (the first error). The second error is an artifact of how the GNU
Radio ALSA source block is written.


Johnathan C.
Corgan Enterprises LLC
http://corganenterprises.com/

The command line is

./tx_voice.py -f 991e5 -T A -r 8000


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On 2/9/08, [email protected] [email protected] wrote:

The command line is

./tx_voice.py -f 991e5 -T A -r 8000

Then it appears you either don’t have an ALSA input configured, or it
does not support 8000 Hz sampling rate.


Johnathan C.
Corgan Enterprises LLC
http://corganenterprises.com/

Thank you for your help Johnathan. Looks like I figured out the issue
with Alsa and opened the channels using alsamixer. I was choosing the
wrong hardware and now I am using hw:00,04 which seems to work with
sampling rate 44.1K.

command line: sudo ./tx_voice.py -f 991e5 -v -I hw:00,04 -M 1

I now get this on the terminal:

gr_fir_fff: using SSE
bits per symbol = 1
Gaussian filter bt = 0.35
Using TX d’board A: Basic Tx
Tx amplitude 12000
modulation: gmsk_mod
bitrate: 50kb/s
samples/symbol: 5
interp: 512
Tx Frequency: 99.1M
gr_buffer::allocate_buffer: warning: tried to allocate
992 items of size 33. Due to alignment requirements
4096 were allocated. If this isn’t OK, consider padding
your structure to a power-of-two bytes.
On this platform, our allocation granularity is 4096 bytes.
aO…




What I am trying to do now is to transmit whatever I play on the
computer (songs) and receive it on a regular FM radio in the room. I see
a pulse at the 99.1M frequency using the usrp_fft.py how ever I cannot
hear anything on the radio. Could you please give me some guidance on
that.

Thanks a bunch!


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On Sun, 10 Feb 2008 15:32:03 -0500, [email protected] wrote:

bits per symbol = 1
Gaussian filter bt = 0.35
Using TX d’board A: Basic Tx
Tx amplitude 12000
modulation: gmsk_mod

Looks like you’re using a gmsk modulation

[…]

What I am trying to do now is to transmit whatever I play on the
computer (songs) and receive it on a regular FM radio in the room. I
see a pulse at the 99.1M frequency using the usrp_fft.py how ever I
cannot hear anything on the radio. Could you please give me some
guidance on that.

If you want to receive the audio on the FM radio, you probably should
transmit in wfm, not using an gmsk modulation (which is a digital
transmission). The blks2/wfm_tx block should do.


Best Regards,
ChoJin