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:address@hidden
Sent: 15 March 2016 15:44
To: Yan Huang
Cc: Martin Braun; address@hidden
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))
2016-03-15 12:14 GMT+01:00 Yan Huang <address@hidden>:
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=address@hidden [mailto:discuss-gnuradio-bounces+eexyh22=address@hidden]
On Behalf Of Martin Braun
Sent: 15 March 2016 00:43
To: address@hidden
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=address@hidden
> [discuss-gnuradio-bounces+eexyh22=address@hidden] on behalf
> of Martin Braun [address@hidden]
> Sent: 14 March 2016 17:18
> To: address@hidden
> 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
>>
>>
>>
>>
>>
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