[Hackrf-dev] Can hackrf support 23.04M sampling rate?

[Jiao Xianjun]

Thank you Hande and Ossmann.

I change to another desktop computer, and get 39.8 MiB/second. Seems that I
have to use 19.2Msps to receive 20MHz LTE. (The actual BW of 20MHz LTE is
around 18MHz: 100RB*180kHz/RB).
According to LTE spec, 20MHz LTE actually is described by 30.72Msps
sampling rate. 19.2Msps can be interpolated to 30.72Msps by 19.2*8/5.

If 23.04Msps can be supported, a simpler interpolation scheme can be used:
23.04*4/3.

BR

Jiao Xianjun



On Mon, May 5, 2014 at 4:33 AM, Russell Hande <zefie at persona.cc> wrote:


> Also it depends on what is in use on that USB hub. Many laptops bundle

> internal components, such as a bluetooth module, or the webcam into an

> internal USB hub. Personally I've only had luck on USB3 ports since

> they have more bandwidth to share across multiple devices.

>

> On Sun, May 4, 2014 at 2:11 PM, Michael Ossmann <mike at ossmann.com> wrote:

> > I can get 21.5 Msps reliably on one USB port on my laptop.  That is the

> > fastest consistent speed I have seen.  The maximum speed seems to depend

> > on the USB host controller.

> >

> >

> > On Sun, May 04, 2014 at 09:16:42PM +0800, Jiao Xianjun wrote:

> >>

> >> I change to another usb port, the rate is increased to 38.3MiB/second.

> >> Seems that it is impossible for my computer (thinkpad T410) to support

> rate

> >> larger than 19.15Msps?

> >>

> >>

> >> On Sun, May 4, 2014 at 9:07 PM, Jiao Xianjun <putaoshu at gmail.com>

> wrote:

> >>

> >> > Hi,

> >> >

> >> > I try to run hackrf at 23.04Msps, and get:

> >> >

> >> >

> >> >

> ------------------------------------------------------------------------------------------------

> >> > hackrf_transfer -f 2000000000 -r tmp.bin -n 100000000 -s 23040000

> >> > call hackrf_sample_rate_set(23040000 Hz/23.040 MHz)

> >> > call hackrf_baseband_filter_bandwidth_set(20000000 Hz/20.000 MHz)

> >> > call hackrf_set_freq(2000000000 Hz/2000.000 MHz)

> >> > samples_to_xfer 100000000/100Mio

> >> > Stop with Ctrl-C

> >> > 34.1 MiB / 1.000 sec = 34.1 MiB/second

> >> > 34.3 MiB / 1.000 sec = 34.3 MiB/second

> >> > 34.1 MiB / 1.000 sec = 34.1 MiB/second

> >> > 34.3 MiB / 1.000 sec = 34.3 MiB/second

> >> > 34.3 MiB / 1.000 sec = 34.3 MiB/second

> >> > 28.8 MiB / 1.000 sec = 28.8 MiB/second

> >> >

> >> > User cancel, exiting...

> >> > Total time: 6.00102 s

> >> > hackrf_stop_rx() done

> >> > hackrf_close() done

> >> > hackrf_exit() done

> >> > fclose(fd) done

> >> > exit

> >> >

> >> >

> ------------------------------------------------------------------------------------------------

> >> >

> >> > Does that mean hackrf support 23.04Msps, but seems there is packet

> loss?

> >> > (according to reported MiB/second)

> >> >

> >> > BR

> >> >

> >> > Jiao Xianjun

> >> >

> >> >

> >

> >> _______________________________________________

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> >> HackRF-dev at greatscottgadgets.com

> >> http://nine.pairlist.net/mailman/listinfo/hackrf-dev

> >

> > _______________________________________________

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>

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