Hi Glen, > Yes.. you can improve the demod to cope with multipath, but for a flat > fading channel like 2m or 70cm, it does not matter how good your demod > is if you have no signal when you stop at the traffic lights..... that > is why the system needs some sort of diversity. It doesnt matter what > type, space, frequency, site just some type. If one was to use DSSS/CDMA to achieve frequency diversity (say on 70cm where there is a bit more bandwidth), how much RF bandwidth would be required to greatly reduce multipath fading effects to the receiver? (and with a linear RX you could also do clever things like use a "rake" demodulator).
Also, instead of using BPSK modulation for DSSS/CDMA, if one was to use MSK modulation instead (+/- 90 degree phase shift instead of +/- 180 degree), would there be a reason why a non-linear transmit chain could not be used? (as far as the TX is concerned it's just high speed MSK). 73 ZL2WRW Ross Whenmouth ------------------------------------------------------------------------------ Download BIRT iHub F-Type - The Free Enterprise-Grade BIRT Server from Actuate! Instantly Supercharge Your Business Reports and Dashboards with Interactivity, Sharing, Native Excel Exports, App Integration & more Get technology previously reserved for billion-dollar corporations, FREE http://pubads.g.doubleclick.net/gampad/clk?id=190641631&iu=/4140/ostg.clktrk _______________________________________________ Freetel-codec2 mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/freetel-codec2
