Re: Help to remove DC offset

no, but I proposed a different way in my first reply.

On 15.02.24 12:41, Arhum Ahmad wrote:
> Yes, in that case, could we reduce the strength of DC so that it won't interfere while
> detecting the signal's frequency (on the run)?
>
> On Thu, Feb 15, 2024 at 4:40 PM Marcus Müller <marcus.mueller@ettus.com
> <mailto:marcus.mueller@ettus.com>> wrote:
>
> __
>
> Hey,
>
> can we keep this on the mailing list, please?
>
> But logically, if you have signal of interest where your DC is, then a high-pass
> filter is not an option.
>
> Best,
> Marcus
>
> On 15.02.24 10:55, Arhum Ahmad wrote:
>> Hey Marcus,
>> I am using it to find the signal frequency present in the given band. However, in
>> some cases, I found DC is more dominant, and I am unable to detect the presence of
>> the signal and its frequency.
>> If I use the high pass filter to remove the DC offset, how should I calculate the
>> cut-off? Considering the fact that there might be a signal at the center.
>>
>> On Sun, Feb 11, 2024 at 10:52 PM Marcus Müller <marcus.mueller@ettus.com
>> <mailto:marcus.mueller@ettus.com>> wrote:
>>
>> Hi Arhum,
>>
>> some limited amount of DC offset is sadly to be expected from any direct
>> conversion architecture (that's a result of LO leakage as well as systematic DC
>> offset).
>>
>> Since DC is the lowest of all possible frequencies, a high-pass filter can be
>> used to eliminate it. The design of that filter depends on what you want to do
>> with the signal afterwards – for example, for some communication system signals,
>> the DC offset literally doesn't matter.
>>
>> Another option is, if your signal is sufficiently more narrowband than the
>> Nyquist bandwidth dictated by your receiver's sampling rate, to "offset-tune";
>> i.e., to put your signal of interest to the positive (or negative) side of your
>> LO frequency, and then digitally shift the signal of interest to actual baseband
>> and filter.
>>
>> The USRPs bring that functionality out of the box, integrated into the device's
>> digital part, so you can just deal with the signal decimated to the bandwidth
>> you need in your computer. I'm not sure, but I don't think the HackRF allows for
>> that. You'd have to offset-tune within your full sampling rate, and in GNU Radio
>> use something like the "freq. X-lating FIR filter" to get the part of the
>> spectrum you want.
>>
>> Best regards,
>> Marcus
>>
>> On 10.02.24 12:02, Arhum Ahmad wrote:
>>> Hey all,
>>>
>>> I'm currently working on frequency sensing using the HackRF SDR. However, when
>>> I calculate the FFT, I encounter a DC offset that's higher than the actual
>>> signal strength itself. This offset is interfering with my ability to detect
>>> the intended output accurately. Could you please assist me in understanding how
>>> to remove this DC offset?
>>>
>>> --
>>> *Thanks and Regards**
>>> *
>>> *Arhum Ahmad*
>>> Ph.D. Scholar, Electrical Engineering Department, IIT Ropar
>>>
>>> +91- <tel:+91-7015802356>7974897279 | arhum.19eez0005@iitrpr.ac.in
>>> <mailto:2016eez0009@iitrpr.ac.in>
>>>
>>> Lab No. 323, Communication Research Lab, J.C.Bose Building
>>>
>>>
>>> *
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>>
>>
>>
>> --
>> *Thanks and Regards**
>> *
>> *Arhum Ahmad*
>> Ph.D. Scholar, Electrical Engineering Department, IIT Ropar
>>
>> +91- <tel:+91-7015802356>7974897279 | arhum.19eez0005@iitrpr.ac.in
>> <mailto:2016eez0009@iitrpr.ac.in>
>>
>> Lab No. 323, Communication Research Lab, J.C.Bose Building
>>
>>
>> *
>> /CONFIDENTIALITY NOTICE: The contents of this email message and any attachments are
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>
>
>
> --
> *Thanks and Regards**
> *
> *Arhum Ahmad*
> Ph.D. Scholar, Electrical Engineering Department, IIT Ropar
>
> +91- <tel:+91-7015802356>7974897279 | arhum.19eez0005@iitrpr.ac.in
> <mailto:2016eez0009@iitrpr.ac.in>
>
> Lab No. 323, Communication Research Lab, J.C.Bose Building
>
>
> *
> /CONFIDENTIALITY NOTICE: The contents of this email message and any attachments are
> intended solely for the addressee(s) and may contain confidential and/or privileged
> information and may be legally protected from disclosure. If you are not the intended
> recipient of this message or their agent, or if this message has been addressed to you in
> error, please immediately alert the sender by reply email and then delete this message and
> any attachments. If you are not the intended recipient, you are hereby notified that any
> use, dissemination, copying, or storage of this message or its attachments is strictly
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