Thanks for your response and please, forgive the delay in responding.
I recorded the different sampling rates and the warnings that sometimes
appeared for some sampling rates.
For example, when I set samp_rate=960kHz, it gave this message:
** UHD Warning:
The requested decimation is odd; the user should expect CIC rolloff.
Select an even decimation to ensure that a halfband filter is enabled.
decimation = dsp_rate/samp_rate -> 65 = (58.880000 MHz)/(0.910000 MHz)
But, on the other hand, when I set samp_rate= 650 kHz -- that is to say,
then the noise level doe NOT take a 20 dB jump -- it gave me the same
message:
** UHD Warning:
The requested decimation is odd; the user should expect CIC rolloff.
Select an even decimation to ensure that a halfband filter is enabled.
decimation = dsp_rate/samp_rate -> 65 = (41.600000 MHz)/(0.640000 MHz)
In both cases I warned about CIC roll-off, but one of them has the 20dB
jump and the other does not.
As per your instructions, I checked a "bad" one surrounded by two "good"
ones:
Trial 1:
samp_rate=110kHz Average_noise=-83dBFS asking_clock_rate=56.32MHz &
samp_rate=120kHz Average_noise=-67dBFS asking_clock_rate=61.44MHz&
samp_rate=130kHz Average_noise=-82dBFS asking_clock_rate=33.22MHz
no warnings about sampling rate in any of the three
Trial 2:
samp_rate=220kHz Average_noise=-82dBFS asking_clock_rate=56.32MHz &
samp_rate=240kHz Average_noise=-64dBFS asking_clock_rate=61.44MHz &
samp_rate=250kHz Average_noise=-81dBFS asking_clock_rate=32MHz
Only one message showed up for samp_rate=250kHz (which does not suffer 20dB
jump):
** UHD Error:
recv packet demuxer unexpected sid 0x20020a0
D
Any ideas?
Thanks again for your time.
Regards
On Mon, Oct 15, 2018 at 11:18 AM Marcus D. Leech via USRP-users <
[email protected]> wrote:
> On 10/15/2018 10:41 AM, Mercado, Alejandra via USRP-users wrote:
>
> Sure thing:
>
> - UHD version UHD_003.010.003
> - GnuRadio version 3.7.9rc1
> - Running on Ubuntu 16.04
>
> Thanks for your help
>
>
> You should look for messages from UHD about failing to set the requested
> sample rate.
>
> It would also be instructive to look at an FFT at the "troublesome" sample
> rates and compare against the closest "good" sample rate.
>
> Given your configuration--0dB gain, and a shorted antenna input, you'll be
> looking entirely at internal noise, which can have a spur population
> that will vary with sample rate.
>
>
>
> On Mon, Oct 15, 2018 at 10:08 AM Michael Dickens <
> [email protected]> wrote:
>
>> OK thanks, Ale; maybe you did say; now we really do know ;)
>>
>> Related: What version of UHD are you using?
>>
>> The UHD version does make a difference, as some issues with the B2XY
>> series have been fixed recently that were introduced after the 3.9 LTS
>> release. - MLD
>>
>> On Mon, Oct 15, 2018, at 8:43 AM, Mercado, Alejandra wrote:
>>
>> Dear USRP and GnuRadio folks,
>>
>> My apologies... I thought I had specified that I am using B210.
>>
>> Regards
>>
>>
>> On Fri, Oct 12, 2018 at 9:52 PM Michael Dickens <
>> [email protected]> wrote:
>>
>>
>> Hi Ale - Reducing this query to just the USRP list since I'm guessing if
>> there is any issue its with that side of things. I'll reiterate Marcus'
>> query, and augment it. The performance depends on which USRP and which
>> version of UHD you're using. You didn't mention those. Scripts are
>> important (thanks!), but more info is required. Cheers! - MLD
>>
>>
>>
>
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