Re: BW(Sample Rate) Issue

[Glen Langston]

Hello Cinaed,

I’ve not experienced this problem with Gnuradio you describe, but
in another context, spacecraft communication, we had a simple test setup
that transmitted a fixed pattern of alternating ones and zeros.

However the way error coding was done the lock was always poor.   

For testing purposes you might have much better luck by sending a “sudo-random”
noise sequence that you define and write into the transmit code.    Then
test that this code arrives correctly on the receive side.   

We found the lock was very reliable, for the noise-like sequence.

Hope this helps, but just a guess

Glen


> On Nov 30, 2022, at 3:54 PM, Cinaed Simson <cinaed.simson@gmail.com> wrote:
> 
> Hi Rohith - Ihe minim sampling rate  for the Pluto is in the ball park of 500 
> KHz. 
> 
> See
> 
>   
> https://ez.analog.com/adieducation/university-program/f/q-a/557730/pluto-sdr-sampling-rate
> 
> -- Cinaed
> 
> 
> On 11/30/22 05:54, Rohith Rajan wrote:
>> I am asking a doubt regarding receiver using an  Adalm Pluto SDR
>> In the receiver section we are using Polyphase Clock Sync, Linear Equalizer 
>> and Costas Loop.
>> My doubt is that is the configuration parameters of these blocks are 
>> dependent on the BW of the signal(Sample Rate)
>> 
>> Keeping the parameters as Normal  (In Polyphase Clock Sync block- No of 
>> filters(nfilts) as 32, Loop Bw .0628, RRC filter as
>> 
>> firdes.root_raised_cosine(nfilts, nfilts, 1.0/float(sps), 0.35, 
>> 11*sps*nfilts), sps as 4
>> 
>> ; In Linear Equalizer No of Taps as 15 ;In CostasLoop Loop BW as .0628) when 
>> I set the BW(sample Rate around)1MHz I can receive the datas.
>> 
>> But when I set the BW(Sample Rate) as 125KHz I cannot receive the datas.
>> 
>> Anyone plese tell me what modification I have to make ?
>> 
>