Hello Martin,
If you create a block which input is message and output is float. And
message is arrive discrete just like packet in network, I want the block
output port will output 0 when no message arrive at input port. Can I do
that?
Why I ask this question is that I a while ago I trying to create a
communication system which I defined and there has two kinds of channel one
is control channel and the other one is message channel like the GSM system
I think so, and I'm using FDD. And control channel is using gmsk modulation
and message channel is using fm modulation because I just want to transmit
audio, I using enough BW to avoid aliasing. After gmsk mod and fm mod, I
add them together but result failed, because add block in gnuradio will
wait when two input data and add one-by-one so if if port one data is much
more then port two, and the add will hold port one data and wait port two
data then add one-by-one.
I have recreate the same situation and past in the mail, it is python file
and can test it to check the problem
Here is my setting : I have two source one is audio source and the other is
packet, and I add it together and output to audio sink. Important audio
source will generate data when program start. The first 5 second no packet
is send. After 5 second packet source will send 1000 packets, meantime,
speaker have sound, and if you have say something in first 5 seconds, you
will hear what you say in the first 5 second now.
---------------------------------------------------------
#!/usr/bin/env python
##################################################
# Gnuradio Python Flow Graph
# Title: Top Block
# Generated: Thu Aug 7 20:16:29 2014
##################################################
from gnuradio import eng_notation
from gnuradio import gr
from gnuradio.eng_option import eng_option
from gnuradio.filter import firdes
from optparse import OptionParser
from gnuradio import digital
from gnuradio import audio
from gnuradio import blocks
from time import sleep
class top_block(gr.top_block):
def __init__(self):
gr.top_block.__init__(self, "Top Block1")
##################################################
# Variables
##################################################
self.samp_rate = samp_rate = 32000
##################################################
# Blocks
##################################################
self.digital_gmsk_mod_0 = digital.gmsk_mod( samples_per_symbol=2,
bt=0.35, verbose=False, log=False, )
self.digital_mod_pkts_0 = digital.mod_pkts(self.digital_gmsk_mod_0,
access_code=None, msgq_limit=4, pad_for_usrp=False)
self.audio_source_0 = audio.source(samp_rate, "", True)
self.audio_sink_0 = audio.sink(samp_rate, "", True)
self.blocks_add_xx_0 = blocks.add_vcc(1)
self.blocks_float_to_complex_0 = blocks.float_to_complex(1)
self.blocks_complex_to_real_0 = blocks.complex_to_real(1)
self.blocks_multiply_const_vxx_0 = blocks.multiply_const_vcc((0.01,
))
##################################################
# Connections
##################################################
self.connect((self.blocks_add_xx_0, 0),
(self.blocks_complex_to_real_0, 0))
self.connect((self.blocks_complex_to_real_0, 0),
(self.audio_sink_0, 0))
self.connect((self.audio_source_0, 0),
(self.blocks_float_to_complex_0, 0))
self.connect((self.audio_source_0, 0),
(self.blocks_float_to_complex_0, 1))
self.connect((self.blocks_float_to_complex_0, 0),
(self.blocks_add_xx_0, 0))
self.connect((self.digital_mod_pkts_0, 0),
(self.blocks_multiply_const_vxx_0, 0), (self.blocks_add_xx_0, 1))
def send_pkt(self, payload='', eof=False):
self.digital_mod_pkts_0.send_pkt(payload, eof)
if __name__ == '__main__':
parser = OptionParser(option_class=eng_option, usage="%prog: [options]")
(options, args) = parser.parse_args()
tb = top_block()
tb.start()
sleep(5)
for i in range(0, 1000):
tb.send_pkt('a')
raw_input('Press Enter to quit: ')
tb.stop()
tb.wait()
------------------------------------------
Jeff Guo
2014-08-07 19:07 GMT+08:00 Martin Braun <[email protected]>:
> On 08/07/2014 12:54 PM, 奕佑 wrote:
> > Hello,
> >
> > Is there any way to combine continuous block (like audio source) and
> > discrete block (like message source) ? Question 1
>
> Combine how? You can do that in your own blocks, sure. Maybe stream tags
> are what you want?
>
> > I using add block to add them together, but it failed. It work well when
> > the discrete block output data like continuous block but discrete block
> > means there is not output data continuous, it output data when something
> > trigger.
> >
> > Can I write a block which input is message and output is like float, and
> > output will always generate like 32k samples but input doesn't have 32k
> > samples suppose this block is sync. Is there any solution ? Question 2
>
> You can write a block who's input is message and output is float. I
> didn't really understand the rest of the question.
>
> M
>
>
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> Discuss-gnuradio mailing list
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> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
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