Hi Timothée, Thank you so much, I’ve got the frequency sweeper with your advice.
It’s not the problem about GNU Radio, I added “work” function in my code but actually it’s a message block which do not need a IO stream ports. Many thanks, Yan From: Timothée COCAULT [mailto:timothee.coca...@gmail.com] Sent: 15 March 2016 20:12 To: Yan Huang Cc: Martin Braun; discuss-gnuradio@gnu.org Subject: Re: [Discuss-gnuradio] Change frequency in USRP source automatically I know I had some problems with older versions of GNU Radio with Python block and message ports breaking my flowgraph. I don't know for sure if it's the same problem though. Try to install the latest GNU Radio in a new prefix, or you could re-code this blocks in C++ in an OOT module. Cheers, Timothée. 2016-03-15 18:58 GMT+01:00 Yan Huang <eexy...@nottingham.ac.uk<mailto:eexy...@nottingham.ac.uk>>: Hi Timothée, Thank you very much, I have built a python block as you suggested and then put it between the strobe and the USRP source, but it come up error like: File "/home/mint/Documents/test_sensor/scan/scan.py", line 154, in <module>tb = scan() File "/home/mint/Documents/test_sensor/scan/scan.py", line 123, in __init__ self.msg_connect((self.blocks_message_strobe_0, 'strobe'), (self.freq_sweeper_frequency_sweeper_0, 'in')) File "/usr/local/lib/python2.7/dist-packages/gnuradio/gr/hier_block2.py", line 60, in wrapped func(self, src.to_basic_block(), srcport, dst.to_basic_block(), dstport) File "/usr/local/lib/python2.7/dist-packages/gnuradio/gr/hier_block2.py", line 132, in msg_connect self.primitive_msg_connect(*args) File "/usr/local/lib/python2.7/dist-packages/gnuradio/gr/runtime_swig.py", line 4472, in primitive_msg_connect return _runtime_swig.top_block_sptr_primitive_msg_connect(self, *args) RuntimeError: invalid msg port in connect() or disconnect() File " The GNU Radio version is GNU Radio Companion v3.7.6.1-65-g500517ac, do you know where is the problem? Many thanks, Yan From: Timothée COCAULT [mailto:timothee.coca...@gmail.com<mailto:timothee.coca...@gmail.com>] Sent: 15 March 2016 16:24 To: Yan Huang Cc: Martin Braun; discuss-gnuradio@gnu.org<mailto:discuss-gnuradio@gnu.org> Subject: Re: [Discuss-gnuradio] Change frequency in USRP source automatically The easiest way would be to create a simple Python block between the strobe and the USRP source : ### class frequency_sweeper(gr.sync_block): def __init__(self, initial_freq=2.37e9, step=2e6): # only default arguments here gr.sync_block.__init__( self, name='Frequency sweeper', in_sig=[], out_sig=[] ) self.message_port_register_in(pmt.intern('clock')) self.set_msg_handler(pmt.intern('clock'), self.handler) self.message_port_register_out(pmt.intern('sync')) self.freq = initial_freq self.step = step def handler(self, pdu): self.message_port_pub(pmt.intern('sync'), pmt.cons(pmt.intern("freq"), pmt.to_pmt(self.freq))) self.freq += self.step ### Cheers, Timothée. 2016-03-15 16:52 GMT+01:00 Yan Huang <eexy...@nottingham.ac.uk<mailto:eexy...@nottingham.ac.uk>>: Hi Timothée, Thank you for your advice. But if I want to change the center frequency from 2.37GHz-2.43GHz with each time stepping 2MHz, how can I realize it by” Message Strobe”? Many thanks, Yan From: Timothée COCAULT [mailto:timothee.coca...@gmail.com<mailto:timothee.coca...@gmail.com>] Sent: 15 March 2016 15:44 To: Yan Huang Cc: Martin Braun; discuss-gnuradio@gnu.org<mailto:discuss-gnuradio@gnu.org> Subject: Re: [Discuss-gnuradio] Change frequency in USRP source automatically Hi Yan, You should only pass only one value in the second member. Try : pmt.cons(pmt.intern("freq"), pmt.to_pmt(2.4e9)) Cheers, Timothée. 2016-03-15 12:14 GMT+01:00 Yan Huang <eexy...@nottingham.ac.uk<mailto:eexy...@nottingham.ac.uk>>: Hi Martin, Thank you, it works well. But I want to change the frequency automatically, so I change the frequency to array like: pmt.cons(pmt.string_to_symbol("freq"),pmt.to_pmt(numpy.array([2.4e9,2.45e9],dtype=numpy.float32))) and I also import numpy in GNU Radio, but it comes up with error : thread[thread-per-block[10]: <block gr uhd usrp source (1)>]: pmt_to_double: wrong_type : #[2.4e+09 2.44999987e+09] Thanks, Yan -----Original Message----- From: discuss-gnuradio-bounces+eexyh22=nottingham.ac...@gnu.org<mailto:nottingham.ac...@gnu.org> [mailto:discuss-gnuradio-bounces+eexyh22<mailto:discuss-gnuradio-bounces%2Beexyh22>=nottingham.ac...@gnu.org<mailto:nottingham.ac...@gnu.org>] On Behalf Of Martin Braun Sent: 15 March 2016 00:43 To: discuss-gnuradio@gnu.org<mailto:discuss-gnuradio@gnu.org> Subject: Re: [Discuss-gnuradio] Change frequency in USRP source automatically Yan, simply convert "freq" and your frequency to a PMT before passing into cons(). Cheers, Martin On 03/14/2016 03:44 PM, Yan Huang wrote: > Hi Martin, > > Thank you for your kind reply. But I'm still comfused that I already have to > input in pmt::cons("freq",2.4e9), cause in the manual it said: > > pmt::cons(KEY, VALUE): This format is useful for commands that take a single > value. Think of KEY and VALUE as the argument name and value, respectively. > For the case of the QT GUI Frequency Sink, KEY would be "freq" and VALUE > would be the new center frequency in Hz. > > Could you please give me an exmaple about it? > > Thank you a lot, > > Yan > ________________________________________ > From: > discuss-gnuradio-bounces+eexyh22=nottingham.ac...@gnu.org<mailto:nottingham.ac...@gnu.org> > [discuss-gnuradio-bounces+eexyh22=nottingham.ac...@gnu.org<mailto:nottingham.ac...@gnu.org>] > on behalf > of Martin Braun [martin.br...@ettus.com<mailto:martin.br...@ettus.com>] > Sent: 14 March 2016 17:18 > To: discuss-gnuradio@gnu.org<mailto:discuss-gnuradio@gnu.org> > Subject: Re: [Discuss-gnuradio] Change frequency in USRP source > automatically > > Yan, > > check the PMT manuals. cons() takes 2 PMTs as input. > > > Cheers, > Martin > > On 03/14/2016 09:09 AM, Yan Huang wrote: >> Hi all, >> >> >> >> I want to change the frequency in "USRP source" automatically, for >> example 2.37GHz-2.43GHz with each time stepping 2MHz. >> >> >> >> 1. As you know, the USRP source has an input message port, so I want >> to connect it to a "Message strobe" to control the frequency change. >> But after I see [1][2], I write PMT type commands in "Message PMT" >> in "Message Strobe" as: >> >> pmt::cons("freq",2.4e9) >> >> it comes up error "invalid syntax(<string>,line 1)", so I don't know >> how to further stepping the frequency. >> >> 2. If I use the "Message Strobe" to define frequency, what can I put >> in the "frequency" in "USRP source" block? Put it as 0? >> >> >> >> [1] https://gnuradio.org/doc/doxygen/page_uhd.html#uhd_command_syntax >> >> [2] >> https://gnuradio.org/doc/doxygen/page_msg_passing.html#msg_passing_co >> mmands >> >> >> >> Many thanks , >> >> >> >> Yan >> >> >> >> >> >> This message and any attachment are intended solely for the addressee >> and may contain confidential information. If you have received this >> message in error, please send it back to me, and immediately delete it. >> >> Please do not use, copy or disclose the information contained in this >> message or in any attachment. Any views or opinions expressed by the >> author of this email do not necessarily reflect the views of the >> University of Nottingham. >> >> This message has been checked for viruses but the contents of an >> attachment may still contain software viruses which could damage your >> computer system, you are advised to perform your own checks. Email >> communications with the University of Nottingham may be monitored as >> permitted by UK legislation. >> >> >> >> _______________________________________________ >> Discuss-gnuradio mailing list >> Discuss-gnuradio@gnu.org<mailto:Discuss-gnuradio@gnu.org> >> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >> > > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org<mailto:Discuss-gnuradio@gnu.org> > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > > > > This message and any attachment are intended solely for the addressee > and may contain confidential information. If you have received this > message in error, please send it back to me, and immediately delete it. > > Please do not use, copy or disclose the information contained in this > message or in any attachment. 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