On 28/09/2011 11:19 AM, Matt Ettus wrote:
On Wed, Sep 28, 2011 at 5:18 AM,
Konstantinos <address@hidden>
wrote:
Hi again,
I recently found out that the Bandwidths of the XCVR 2450
Daugtherboard are as
follows for the RX and TX side respectively:
Bandwidths (Hz):
RX: 15M, 19M, 28M, 36M; (each +-0, 5, or 10%)
TX: 24M, 36M, 48M
Can someone elaborate on these values please and how to decide
upon which one to
use? As I can understand, this is dependent on the specific
application,
however, I am puzzled as to why they are different since these
values correspond
to the bandwidth allowed in the bandpass filter prior to
transmission/reception.
These filters are programmable low-pass filters which
operate at baseband. In general, you just need to set them
wide enough for the signals you wish to deal with.
Matt
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My impression is that, except in special circumstances, the analog
filters are set "appropriately", if the hardware has settable
filters.
The analog bandwidth should generally be set to be somewhere less
than Fs/2, for whatever Fs is in use on the motherboard--
64Msps on the USRP1/E100 and 100Msps on the USRP2/N2XXX family.
Since the FPGA normally does digital filtering, as long
as the analog bandwidth is set to less than Fs/2, you shouldn't
need to adjust the filters, and I think UHD does this automatically.
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