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From: | Marcus D. Leech |
Subject: | Re: [Discuss-gnuradio] can I set bandwidth for rfx1800 board |
Date: | Mon, 27 Dec 2010 22:07:13 -0500 |
User-agent: | Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.12) Gecko/20101103 Fedora/1.0-0.33.b2pre.fc14 Thunderbird/3.1.6 |
On 12/27/2010 09:55 PM, James Jordan wrote:
Hi all, I check gnuradio code found set_bw( ) is not implemented in db_flexrf_900_rx_mimo_b.Only cards that have a variable low-pass hardware filter on their baseband outputs can process set_bw(). I believe that only the DBS_RX and DBS_RX2 have this functionality--the MAX2118 (DBS_RX) and MAX2112 (DBS_RX2) both have programmable switched-capacitor filters integrated into the quadrature downconverter chip. The RFX series cards have a fixed hardware filter giving a roughly 20MHz low-pass characteristic on the mixer output. When this is sampled at either 64MHz (USRP1) or 100MHz (USRP2), and then digitally filtered with the CIC decimator, the out-of-band content should be very far down. -- Marcus Leech Principal Investigator Shirleys Bay Radio Astronomy Consortium http://www.sbrac.org |
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