Re: Shifting frequency spectrum

[Snehasish Kar]

I tuned the usrp to 947.4MHz with sample rate of 25msps. And then using the 
example in the link I tried shifting the frequency to the centre, so that I can 
apply a low pass filter and perform resampling on it.

BR
Snehasish

Sent from my iPad

> On 11-Nov-2019, at 10:02 PM, Müller, Marcus (CEL) <address@hidden> wrote:
> 
> Hi Snehashish,
> 
> it's not really clear what you did exactly. How did you do the
> shifting? Did you already take the mixing (probably by 947.4 MHz) done
> by your SDR freontend into account?
> (Also, frequencies and bandwidths have units!) 
> 
> Best regards,
> Marcus
> 
>> On Mon, 2019-11-11 at 14:55 +0000, Snehasish Kar wrote:
>> Hello 
>> 
>> I tried capturing GSM 900 band at a sample rate of 25e6 centered at 947.4e6 
>> and stored in a file. Then on the captured data I tried shifting 935.2e6 to 
>> the center and perform a low pass filter samples out followed by a 
>> re-sampler to get 200e3 samples out. But I think the spectrum shifting is 
>> not wroking as it should be I am following the following link for spectrum 
>> shifting https://dsp.stackexchange.com/a/1993. I am using twinrx with 10gig 
>> sfp, UHD_3.13.1.0-0-unknown, ubuntu 16.04 and liquid dsp for signal 
>> processing.
>> fft - How to shift the frequency spectrum? - Signal Processing Stack Exchange
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>> Please let me know, where I might be going wrong.
>> 
>> BR
>> Snehasish
>>