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From: steveu on 21 Mar 2010 22:10 >dvsarwate <dvsarwate(a)gmail.com> wrote: > >>But Eric's point about comm specsmanship brings to mind >>an apocryphal story about how IBM won a contract for a >>military comm. system. Both the IBM design and the >>had the same data rate and same BER but the IBM design >>used a rate 1/2 code while the competing design used a >>rate 2/3 code. (The OP who is no doubt thoroughly bewildered >>by the hijacking of this thread should work out what the >>implications are for transmitter power and bandwidth in the >>two designs). Anyway, IBM won because they told the >>generals "In our system, we use one parity bit to protect >>each data bit, whereas in the Brand X system each parity >>bit has to protect *two* data bits and so their system >>provides only half as much data protection as ours does." > >Brilliant. > >I'd bet someone a beer this was a system where the delivered >datarate was an open figure, but the modulation order (and >therefore, code rate) was classified. These kinds of thing are usually said by a salesman. An engineer couldn't say them with a straight face. The salesman often genuinely believe what they are saying to be realistic. :-) Steve |