Please see my comments in-line below
-Tim -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Mark Whatley Sent: Monday, June 29, 2009 8:55 AM To: [email protected] Subject: [Flexradio] Sound card questions Hello all, I've been doing a lot of reading before deciding on buying a FlexRadio. I'm still a bit confused about the sound card requirements. The computer that I would like to use currently has a SB Live 24 bit external sound device. But it is not in the supported list of sound cards. But I see this Q and A in the FAQs on the web site: Q3: Does the FLEX-3000 need a sound card to operate? A: The need for an external sound card to provide the A/D and D/A conversions of the I/Q signals was a requirement only for first generation software defined radios, such as the SDR-1000 other SDRs that utilize the SDR-1000 architecture. All second generation and beyond SDRs from FlexRadio Systems, such as the FLEX-3000 do not require a sound card of any kind to operate. The A/D and D/A converters are integrated into the radio hardware. So, why do I need a different (and expensive) sound card? Also, in the KC article about the supported sound cards I see a note that some contain a microphone preamp and some don't. It looks like the microphone connects directly to the radio - so is the lack of a preamp important? [Tim] You don't. Look at the "Applicable Hardware" designator in the KC article at the top. The article you reference is applicable ONLY to the SDR-1000 I have loaded the demo and then the 1.18.1 release. I had a few problems in getting it to run on the intended system (Dell 3GHz single core XP Pro). Finally found the right combo of sample rate/buffer size/audio device(48000,1024,MME). But almost any deviation from 48000 sample rate and 1024 buffer size will crash the program. These parameters seem to relate to the sound card and add to my confusion about the sound card requirements. I understand that in the demo I don't have a radio and possibly the sound interface is more critical. [Tim] For the demo, you do need a sound card because something has to do the D/A conversion and the sound card performs that function for a system that does NOT have radio hardware attached. If I understand all this correctly I can hook the FxK box to my computer, install the software, plug a mic into the FxK, plug a set of headphones in, and connect a PS and antenna and get on the air. Without a sound card at all. [Tim] This is 100% correct I'm guessing that most people would want to listen to the receive audio on speakers. [Tim] Most people use high fidelity computer speakers connected directly to the FLEX-x000 So if I want to listen to the audio via my computer speakers then I'll need a sound interface of some kind (or a separate set of powered speakers)- but do I really need one of the supported cards? [Tim] If you want to use computer speakers connected to your computer as opposed to connecting them directly to the FLEX-3000, then yes, you need to connect the audio output of the FLEX-x000 to the PC's sound card, but as stated before, a computer sound card is not required for the FLEX-x000 SDRs. My SB seems to do a good job with everything else I listen to. If I want to feed receive audio to my PC speakers and operate RTTY using MMTY do I need two sound cards? [Tim] No, you do not need any sound cards. You can transfer audio directly from PowerSDR to the digi mode program using VAC. I've read through the VAC articles so I follow the basic ideas. But the VAC articles show how to route one audio stream between the radio and the sound card used for the digital mode. What about the receive audio stream? [Tim] VAC is bidirectional routing both RX and TX audio and it doesn't route audio to the sound card, per se, it routes it directly to the sound card based digi mode program without having to perform an A/D conversion so all of the audio is kept in the digital domain for the cleanest digi mode signal possible (BTW, the FLEX is the only radio than can do this). In all the research I've been doing on this I have probably missed something that would have answered my questions. I've learned a lot however. I'm hoping to replace my old FT-1000 with a FlexRadio. Thanks to all on the reflector - your posts have been helpful. 73, Mark K5XH _______________________________________________ FlexRadio Systems Mailing List [email protected] http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/ _______________________________________________ FlexRadio Systems Mailing List [email protected] http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/
