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From: | Ron Economos |
Subject: | Re: [Discuss-gnuradio] DVB-S2 Physical Layer Framer: Why outputs a zero after each sample? |
Date: | Sun, 19 Jun 2016 18:28:02 -0700 |
User-agent: | Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.8.0 |
The intended application for the DVB-S2 transmitter in GNU Radio was
mostly for digital television over amateur radio. The example flow
graph transmits a 6 MHz wide signal (5 Msyms/s and 20% excess
bandwidth), which is about as wide as folks want to use on ham
bands. Most amateurs are using less bandwidth and a few are using
narrow bandwidths (in the UK, there's a temporary digital allocation
at 146 to 147 MHz, and the typical symbol rate is 333 ksyms/s). So the 2X oversampling didn't seem like too much of a burden. Pretty much all transmit capable SDR's can handle 10 Msps. If you're interested in really wide bandwidth transmission, then the 2X oversampling does get in the way a little. On my workstation with a B210 and Via USB3.0 controller, I can run 20 Msyms (40 Msps) reliably for a 24 MHz wide signal. Above that rate, it falls apart with underruns. With an optimum USB3.0 controller capable of 60 Msps, it should be possible to do a commercial satellite transponder 36 MHz wide signal with a B2X0. Ron On 06/16/2016 12:36 PM, Francisco
Albani wrote:
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