Hi David, for the estimation I used a commercial tool called SysCalc, developed by Arden Technologies, Inc. The input data have been assumed: Frontend BPF: typ. 2 dB NF, 2 dB insertion loss, OIP3 50 dBm; NE6o2: 5 dB NF, 17 dB gain, -12 dBm OIP3; channel filter: 3 dB NF, 3 dB insertion loss, OIP3 100 dBm; ADC: 50 dB NF (!)
My only intention was to prevent disappointment, hi. 73, Helmut, DC6NY -----Ursprüngliche Nachricht----- Von: David Rowe [mailto:[email protected]] Gesendet: Mittwoch, 25. Februar 2015 23:08 An: [email protected] Betreff: Re: [Freetel-codec2] Simple SDR for VHF FreeDV Hi Helmut, Can you please tell me how you worked that out? My next step is to add gain to balance MDS and IP3 but not sure how you obtained those numbers! Yes the radio as it stands requires another design pass. At this stage it is a "proof of concept" to test the novel features: such as the use of a uC for most of the tuning, and extreme hardware simplicity. Thanks, David On 26/02/15 08:09, Helmut wrote: > Hello David, > > a rough simulation of that SDR design predicts a rather deaf radio: > Total noise figure = 38 dB, MDS=-95dBm @ 12,5kHz System BW, Input IP3 = -20 dBm. > I would suggest at least a 20 dB preamp with high IP3 performance in > front of the ADC. So you will achieve a MDS of -114 dBm. Sure no > splendid value, but will detect some VHF signals, hi. > > 73, Helmut, DC6NY > > -----Ursprüngliche Nachricht----- > Von: David Rowe [mailto:[email protected]] > Gesendet: Dienstag, 24. Februar 2015 22:16 > An: [email protected]; > [email protected] > Betreff: [Freetel-codec2] Simple SDR for VHF FreeDV > > Hello, > > To support VHF FreeDV developments I've been working on a really > simple and very open SDR architecture for VHF radio: > > http://www.rowetel.com/blog/?p=3884 > > Glen and Matt - would appreciate you suggestions on appropriate input > BPF filtering and a VHF mixer. Also pls let me know if you see any > show stoppers in this architecture. > > Cheers, > > David > > ---------------------------------------------------------------------- > ------ > -- > Dive into the World of Parallel Programming The Go Parallel Website, > sponsored by Intel and developed in partnership with Slashdot Media, > is your hub for all things parallel software development, from weekly > thought leadership blogs to news, videos, case studies, tutorials and > more. Take a look and join the conversation now. > http://goparallel.sourceforge.net/ > _______________________________________________ > Freetel-codec2 mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/freetel-codec2 > > > ---------------------------------------------------------------------- > -------- Dive into the World of Parallel Programming The Go Parallel > Website, sponsored by Intel and developed in partnership with Slashdot > Media, is your hub for all things parallel software development, from > weekly thought leadership blogs to news, videos, case studies, > tutorials and more. Take a look and join the conversation now. > http://goparallel.sourceforge.net/ > _______________________________________________ > Freetel-codec2 mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/freetel-codec2 > ---------------------------------------------------------------------------- -- Dive into the World of Parallel Programming The Go Parallel Website, sponsored by Intel and developed in partnership with Slashdot Media, is your hub for all things parallel software development, from weekly thought leadership blogs to news, videos, case studies, tutorials and more. Take a look and join the conversation now. http://goparallel.sourceforge.net/ _______________________________________________ Freetel-codec2 mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/freetel-codec2 ------------------------------------------------------------------------------ Dive into the World of Parallel Programming The Go Parallel Website, sponsored by Intel and developed in partnership with Slashdot Media, is your hub for all things parallel software development, from weekly thought leadership blogs to news, videos, case studies, tutorials and more. Take a look and join the conversation now. http://goparallel.sourceforge.net/ _______________________________________________ Freetel-codec2 mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/freetel-codec2
