[USRP-users] 答复: frequency shift of B210

Marcus Müller marcus.mueller at ettus.com
Mon Jul 24 10:28:57 EDT 2017


Dear John,

at this point my recommendation is: Describe your measurement setup in
more detail, and verify it's useful for measuring the clock quality of
the B210, and not the  of your CC11xx system. In fact, from what you've
described, I can't really say I understand how this measures the clock
offset of the B210 – instead, it only measures how well the CC11xx works
together with your software; I'm having a bit of a hard time seeing how
you can derive statements on the frequency shift from that.

Best regards,

Marcus

On 07/24/2017 11:35 AM, john liu via USRP-users wrote:
> HI,all,
> Do you have any suggestions about this?
> thank you.
> best regards
> John
>
> On Mon, Jul 24, 2017 at 9:15 AM, 戚科峰(研三 福州) <qikefeng at ruijie.com.cn
> <mailto:qikefeng at ruijie.com.cn>> wrote:
>
>     Hi,Marcus,
>
>      
>
>     we use The B210 as a basestation and cc1120 as the tranceiver of UE.
>
>     The B210 uses the Frequency offset estimation algorithm to
>     estimate the frequency offset of cc1120 and records it.
>
>     there are several UE in the system,UE will receive the B210'signal
>     periodically and will send a signal to B210 in another period.
>
>     when the phenomenon of the 3.2k frequency shift occured,all UE
>     could not receive the signal of B210.when time for UE to send a
>     signal,
>
>     B210 would estimate the new frequency shift and found that the
>     Frequency offset of every UE shifts 3.2k。So we think the shifting
>     occured in B210 instead of UE。
>
>      
>
>     best regards
>
>      
>
>      
>
>     *发件人:*john liu [mailto:johncorad1988 at gmail.com
>     <mailto:johncorad1988 at gmail.com>]
>     *发送时间:*2017年7月21日16:42
>     *收件人:*Marcus D. Leech
>     *抄送:*USRP-users at lists.ettus.com
>     <mailto:USRP-users at lists.ettus.com>; 戚科峰(研三 福州)
>     *主题:*Re: frequency shift of B210
>
>      
>
>     Hi,Marcus,
>
>     We calculated this.
>
>     The B210 not only generate a GFSK signal,but also received the
>     signal from CC1120.The CC1120 and B210 both work in full duplex mode.
>
>     Hi qi,
>
>     Can you describe your test method?I am not clear for that.
>
>      
>
>     best regards
>
>     John
>
>      
>
>      
>
>     On Fri, Jul 21, 2017 at 10:47 AM, Marcus D. Leech
>     <mleech at ripnet.com <mailto:mleech at ripnet.com>> wrote:
>
>     On 07/20/2017 10:08 PM, john liu wrote:
>
>         i am sorry.
>
>         We generate a GFSK signal with B210 and  received the signal
>         with multiple cc1120.When frequency shift occurred,the cc1120
>         can not received the signal.
>
>         Also, another b210 has been running for several days without
>         such a jump phenomenon.
>
>     So, sorry to be a bother, but, where did the 3.2kHz frequency
>     shift measurement come from?   The CC1120 is just a GFSK
>     demodulating digital receiver.
>
>
>
>      
>
>     On Fri, Jul 21, 2017 at 9:37 AM, Marcus D. Leech
>     <mleech at ripnet.com <mailto:mleech at ripnet.com>> wrote:
>
>     No i mean what were you measuring?
>
>      
>
>     Were you using an external signal generator and what were its specs?
>
>      
>
>
>     Sent from my iPhone
>
>
>     On Jul 20, 2017, at 9:09 PM, john liu <johncorad1988 at gmail.com
>     <mailto:johncorad1988 at gmail.com>> wrote:
>
>         HI Marcus,
>
>         internal with  TCXO.
>
>          
>
>         On Thu, Jul 20, 2017 at 11:31 PM, Marcus D. Leech
>         <mleech at ripnet.com <mailto:mleech at ripnet.com>> wrote:
>
>         On 07/20/2017 02:22 AM, john liu wrote:
>
>                  
>
>             What was your tuned frequency in this case?
>
>              
>
>             Hi,Marcus,
>
>              
>
>             It is 433.05Mhz
>
>         That's about 7PPM.
>
>         What was your signal source?
>
>
>
>          
>
>         On Thu, Jul 20, 2017 at 11:46 AM, john liu
>         <johncorad1988 at gmail.com <mailto:johncorad1988 at gmail.com>> wrote:
>
>         Hi all,
>
>         We used B210 with TCXO,and run about 2 hours , a 3.2K
>         frequency shift occurred when the temperature did not change
>         significantly.Is it a normal?
>
>         How can we improve this situation?
>
>          
>
>         thank you.
>
>         best regards
>
>         John
>
>          
>
>          
>
>          
>
>      
>
>      
>
>      
>
>
>
>
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