Re: [USRP-users] Using Two DDC Chain in N210

2018-07-30 Thread Marcus D. Leech via USRP-users

On 07/30/2018 12:30 PM, Amirhosein naseri via USRP-users wrote:

Hi everybody

I want to use Two DDC chain in usrp N210 to get streams for example 
around freq0 and freq1 with sample rate 400e3 for each channel.
first i use uhd.tune_request_t function as argument fot 
set_center_freq function as below :


usrp1.set_center_freq ( uhd.tune_request_t (freq1,0) , 0)
usrp1.set_center_freq ( uhd.tune_request_t (freq1,freq2-freq1) , 0)

I got two stream, first correspond to freq1 is true but for second 
stream correspond two freq2 it's not.
second stream has frequency shift equal to sum of CORDIC frequency of 
freq1 and freq2 ...


I test different configuration for arguments of uhd.tune_request_t but 
i can't solve the problem 


anyone has any advice in true usage of uhd.tune_request_t for using 
two DDC chain of N210 ?


Tnx.

You'll have to use the policy arguments to prevent retuning of the RF 
hardware in the second tune.When I have done this in the past, I've
  set the RF hardware to exactly half-way between the two target 
frequencies, and used the DDCs to bring in the frequencies I wanted.


https://files.ettus.com/manual/structuhd_1_1tune__request__t.html


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[USRP-users] Using Two DDC Chain in N210

2018-07-30 Thread Amirhosein naseri via USRP-users
Hi everybody 

I want to use Two DDC chain in usrp N210 to get streams for example around 
freq0 and freq1 with sample rate 400e3 for each channel.first i use 
uhd.tune_request_t function as argument fot set_center_freq function as below : 

usrp1.set_center_freq ( uhd.tune_request_t (freq1,0) , 0)usrp1.set_center_freq 
( uhd.tune_request_t (freq1,freq2-freq1) , 0)
I got two stream, first correspond to freq1 is true but for second stream 
correspond two freq2 it's not.second stream has frequency shift equal to sum of 
CORDIC frequency of freq1 and freq2 ...
I test different configuration for arguments of uhd.tune_request_t but i can't 
solve the problem 
anyone has any advice in true usage of uhd.tune_request_t for using two DDC 
chain of N210 ?
Tnx.
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