Re: [Discuss-gnuradio] Why does I channel have non-zero data for Q direct sampling mode

[Patrick Sathyanathan]

Ok, I read the original thread that discussed the direct sampling mod on the 
google group here: 
https://groups.google.com/forum/#!topic/ultra-cheap-sdr/cG988R1D8uE . That has 
a good explanation of how the mod works.


It seems you do get I/Q samples and not just Q samples as the name "Q branch 
direct sampling" seemed to imply.

[http://www.google.com/images/icons/product/groups-128.png]

What is RTL-SDR direct sampling 
mode?
groups.google.com
Posted 7/15/12 10:52 AM, 25 messages


--Patrick




From: Discuss-gnuradio  on 
behalf of Patrick Sathyanathan 
Sent: Thursday, June 1, 2017 11:22 PM
To: discuss-gnuradio@gnu.org
Subject: [Discuss-gnuradio] Why does I channel have non-zero data for Q direct 
sampling mode


Hi All,


Not sure which forum to direct this question. I am using a Soft66Q device which 
is an rtl-sdr with Q branch direct sampling mod.



I observed the I and Q channels in direct sampling mode using the osmocom_fft 
program in scope mode run as follows:


osmocom_fft --args="rtl,direct_samp=2" -s 2.4M -f 1.2M -S


I expected the I channel to be 0 or a copy of the Q channel. But I see that 
they are different. Why is this so ? Does the gr-osmosdr driver convert the Q 
channel signal to complex I/Q ? And if so how ?


Thanks for any information,


--Patrick


From: Patrick Sathyanathan 
Sent: Thursday, June 1, 2017 6:41 PM
To: kazunori miura
Subject: Re: Fw: ORDER: RTL-SDR Soft66Q 3kHz to 1.7GHz RTL2832U with RF anp 4 
band filter R820T2, VLF


Thanks, Kazunori. The device works very well.


--Patrick


From: kazunori miura 
Sent: Thursday, June 1, 2017 5:40 PM
To: Patrick Sathyanathan
Subject: Re: Fw: ORDER: RTL-SDR Soft66Q 3kHz to 1.7GHz RTL2832U with RF anp 4 
band filter R820T2, VLF

yes, ant input has capacitor.HF and VHF each.

On 2017/06/02 9:36, Patrick Sathyanathan wrote:
> Hi,
>
>
> I want to connect a signal source with a dc bias to the input of
> soft66q. Does the input has dc blocking capacitor ? Or should I provide
> one externally.
>
>
> Thanks,
>
>
> --Patrick
>
>
>
> 
> *From:* eBay 
> *Sent:* Saturday, September 24, 2016 2:19 AM
> *To:* wp...@hotmail.com
> *Subject:* ORDER: RTL-SDR Soft66Q 3kHz to 1.7GHz RTL2832U with RF anp 4
> band filter R820T2, VLF
>
> Confirmed. ETA: Mon. Oct. 24 - Wed. Nov. 9. eBay will update the
> estimate when it ships to 15861 Northup Way.
>
> eBay
> 
>
>
>
>   Hi Patrick - Order confirmed. eBay will update you when your order
>   ships to 15861 Northup Way
>
> PAID : $52.00 with PayPal
>
> View order details
> 
>
>
> RTL-SDR Soft66Q 3kHz to 1.7GHz RTL2832U with RF anp 4 band filter
> R820T2, VLF...
> 
>
>
>
> RTL-SDR Soft66Q 3kHz to 1.7GHz RTL2832U with RF anp 4 band filter
> R820T2, VLF
> 
> 
>
>
> Estimated delivery: Mon. Oct. 24 - Wed. Nov. 9
>
> Item Id: 201660671703
> Transaction Id 1428115037010
> Quantity: 1
>
>
>   To complement your purchase
>
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> PLL LCD 

[Discuss-gnuradio] Bus ports problem -- issue from 2016?

[John Ackermann N8UR]

I've started experimenting with the bus port capability, using 3.7.11.1.

The QT GUI Frequency Sink creates a bus with one more port than the 
number required (possibly a hidden message port).  This was reported as 
a bug last year, and still seems to be a problem.  Is a fix for this on 
the horizon?  Or is there a workaround -- e.g., is it possible to 
separate a bus back to individual ports?


Thanks,
John


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[Discuss-gnuradio] IEEE 802.11 Transceiver Module - Timing offset at receiver side

[Qurat-Ul-Ann Akbar]

Hello,

How is the timing offset being handled in the 802.11 module. I see that the
sync_long block does frequency offset correction and the frame_equalizer
block does the phase correction but I dont understand where is the timing
offset being handled. Can anyone tell me which algorithm is being used to
do that?
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