Re: [Discuss-gnuradio] 2 RX and 1 TX channel

[kaleem ahmad]

Hallo everyone,

I dont get any reply so far, may be I can rephrase my question. 

Actually I was expecting that any code which is working fine for a single
antenna, will only need little changes (Mentioned above in 1st post on this
thread) to convert it to multiple antenna. I mean I was expectring that I
would only need to direct streams of two different antennas to folwgraphs of
my already working code. BUT its not working in this way.

I have read all related posts on this forum and examples related to
multi_usrp in gnuradio_examples but I am unable to understand where I am
doing wrong, I could not find an answer even from "USRP_Documentation", so
please let me know after having a look on code (For code please go above to
first post on this page) where I am doing wrong.

Do I need to take care of decimation rate when I have two RX channels, I am
using 160 for both (I think only restriction for decim rate is that it
should be equal for both. Is there any thing else?). OR are there some
parameters which need to be handeled differently for 2 RX channels?

My understanding about deinterleaver is that, it will get the input from
USRP as a single stream as follows:
self.connect(self.u,self.deinter)
and will automatically and correctly divide it into two separate streams,
and we dont need to do anything else, as follows:
self.connect ((self.deinter,0), self.rx_filter, self.fmdemod, self.corr,
self.vec_sink)
self.connect ((self.deinter,1), self.fft_input)

Is this understanding about deinterleaver correct or do I need to do some
special processing to get these separate streams.


Thanks 

Kaleem AHmad


kaleem ahmad wrote:
> 
> In addition to my above mentioned question, please also comment on what
> should be the value of mux (I am setting 0x3210) and what should be the
> value of fpga_filename,
> 
> Please again note that I want to use 2 RFX2400 cards with one USRP1, and 2
> rx streams will be there each through RX2 antenna of 2 RFX2400 cards and
> there will be one tx stream through any one of these cards.
> 
> Best Regards
> 
> Kaleem Ahmad
> 
> 
> 
> kaleem ahmad wrote:
>> 
>> Hello every one,
>> 
>> I am using USRP1 + RFX2400.
>> 
>> I want to use 2 RFX2400 cards. Overall I will have 2 RX streams and 1 TX
>> stream from this system. Following are main parts of my RX_Path (complete
>> code for RX-Path is also attached, if you want please have a look on
>> that, TX-path is not here). I am unable to receive anything from any of
>> the channels although the same RX-path was working when I was using a
>> sinle antenna. Only following lines were mainly changed. Please have a
>> look and let me know if my configuration for 2 RX (on separate RFX cards,
>> but one USRP1 main board) and one TX channel.
>> 
>> 
>> u = usrp.source_c(0, decim_rate=self.usrp_decim, nchan=2
>> self.subdev = (self.u.db[0][0] , self.u.db[1][0])
>> self.u.set_mux(gru.hexint(0x3210))  
>> 
>> #Set the gain to the midway point
>> self.subdev[0].set_gain(60)
>> self.subdev[1].set_gain(60)
>> 
>> #Set the recieve frequency
>> self.r0 = usrp.tune(self.u, 0, self.subdev[0], 2.41e9)
>> self.r1 = usrp.tune(self.u, 1, self.subdev[1], 2.41e9)
>> 
>> self.subdev[0].select_rx_antenna( 'RX2')        
>> self.subdev[1].select_rx_antenna( 'RX2')
>> 
>> self.deinter = gr.deinterleave(gr.sizeof_gr_complex)        
>> 
>> #enable Auto Transmit/Receive switching
>> self.set_auto_tr(True)
>> 
>> self.connect(self.u,self.deinter)
>> self.connect ((self.deinter,0), self.rx_filter, self.fmdemod, self.corr,
>> self.vec_sink) # One RX antenna for regular data reception
>> self.connect ((self.deinter,1), self.fft_input) #Other RX antenna for fft
>> window, this fft will be further processed
>> 
>>       
>>  http://www.nabble.com/file/p24305532/receive_path.py receive_path.py 
>> 
>> Best Regards
>> 
> 
> 

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