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From: | John Ackermann N8UR |
Subject: | Re: [Discuss-gnuradio] Multiplexing modulators |
Date: | Tue, 21 Jun 2011 15:54:10 -0400 |
User-agent: | Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.17) Gecko/20110516 Thunderbird/3.1.10 |
Thanks, all, for the replies.For my simple test case, I'm trying just two modulators with a frequency translating FIR following each, one set to 0 Hz and the other to +25kHz.
I set the NBFM modulator quadrature outputs to 128ksps, then add them together and feed to the USRP at 256ksps. (At this point, I'm not worrying about gain setting; I know I need to address that but wanted to get the basic flow correct first.)
When I run the program I get this error: UHD Warning: The hardware does not support the requested TX sample rate: Target sample rate: 0.256000 MSps Actual sample rate: 0.255102 MSpsSince I'm summing two 128ksps streams, I thought I'd get a 256ksps stream at the output of the adder. Where are these 898 samples per second disappearing? And how do I correct that? (The single channel version of the program, with the NBFM quadrature rate set directly to 256ksps, worked fine.)
Thanks, John ---- Marcus D. Leech said the following on 06/21/2011 12:33 PM:
On 21/06/2011 12:05 PM, Alexandru Csete wroteSorry, I meant multiply with a complex sine or cosine wave of frequency f, where f is the offset. Marcus suggested using filters, which will also work but it's a bit overkill for a simple translation, isn't it? AlexYes, it's overkill, but I thought it might be the simplest "form" to get working first. _______________________________________________ Discuss-gnuradio mailing list address@hidden https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
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