On 05/07/2019 04:22 PM, Ben Hilburn
wrote:
I don't personally have experience with it, but the
Kerberos SDR might be worth checking out? It's effectively
four coherent rtl-sdrs in a box.
Cheers,
Ben
I would describe the implementation as "coherent-ish". Since the
RTL-SDR has no inherent timestamping or synchronizing ability, one
has
to stand on ones head a bit to get close synchronization with
small phase offset. Simply driving them with a common reference
clock is not
enough--you have to turn off features in the synthesizer, and you
need a multi-party cross-correlation to resolve the phase and timing
ambiguities. Not for the faint of heart, but doable.
Hi Wu,
Thanks for the info. I do not have
experience in FPGA programming. I am planning to use
bladerf as it seems to be easier to synchronize two SDRs
via the driver.
Hi
YENDstudio,
if
you have ability to modify the fpga code you can
use 2 b210 or 2 LIMESDR to achieve that. the
synchronized receive need same phase clock that is
easy to get from a clock buffer from a clock
source. and need the same timestamp of the sample
at the same time. that need to modify the fpga to
reset timestamp and output an start signal from
the GPIO then another sdr receive this signal
reset the timestamp. I think HACKRF use the same
way to do synchronize. but HACKRF use usb 2.0 i
don't know if it support LTE bandwitdh.
provide
SDR, LNA, PA
发件
人: Discuss-gnuradio
<discuss-gnuradio-bounces+john.wu.888=address@hidden>
代表 YENDstudio <address@hidden>
发送时间: 2019年4月26日 11:54
收件人: Kyeong Su Shin
抄送: address@hidden
主题: Re: [Discuss-gnuradio] Two channel
receiver
Hello Kyeong,
Thanks for the
info; I will check more. It
seems that some hardware modifications are
required.
Regards
Hello
YENDstudio,
I
know that USRP 1 can take two RF
daughterboards, but the effective
sampling rate of the device in this
configuration is a bit limited
(probably too slow for LTE
applications).
You
can probably use two SDR boards with
synchronization capabilities (or
synchronization hacks) and a suitable
clock generator. I know that my HackRF
boards can do this ( https://github.com/mossmann/hackrf/wiki/Multiple-device-hardware-level-synchronization
), but I never tried this by myself
(and the sample alignments can be off
by ~50 samples, according to the wiki,
so you have to correct that for the
perfect alignment). I also know that
there are a few cheap SDRs with
synchronization capabilities,like
AirSpy, but I never used them.
You
can make your own RF frontend and add
that to one of the antenna ports of a
LimeSDR-like SDR by using a mixer and
a clock generator (available on RF
components stores, or on
eBay/AliExpress, if you are willing to
deal with dodgey sources). You may
have to add an additional LNA
(LNA4ALL? ) and/or a filter before the
mixer to improve the noise figure (but
you need to make sure that you are not
overloading your SDR by doing so). All
of these parts are available as
SMA-type plug-in modules, and are in
reasonable price, if you are okay with
cheapo eBay/AliExpress parts.
Regards,
Kyeong
Su Shin
보낸 사람: YENDstudio
<address@hidden>
보낸 날짜: 2019년 4월 26일 금요일 오전
1:43
받는 사람: Kyeong Su Shin
참조:
address@hidden
제목: Re: [Discuss-gnuradio]
Two channel receiver
I just wanted to receive
time-synchronized channels.
Hello
YENDstudio,
Do
you actually need a
two-channel receiver?
Maybe you can get away by
using two separate SDRs
(possibly synchronized
with PPS and 10MHz clock)
and a splitter (or two
antennas).
An
another alternative would
be adding a custom mixer (and
a filter, if needed)
between the SDR and the
antenna.
Regards,
Kyeong
Su Shin
Hi,
Does
anyone know any
affordable (not
thousands) SDR which
can receive two
frequencies
separately. I want to
receive LTE UL and DL
channels which can be
more than 100 MHz
appart. The LO offset
in USRP B210 and
Limesdr is not enough
to cover the two
frequencies with a
shared frequency
synthesizer.
Regards
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