Digital Signal Processing and in particular FIR filters permits a levelof performance only bettered by the most expensive mechanical filters.Mechanical filters can be made to perform better than an 'equivalent' softwareFIR filter except they are extremely inflexible. CODE30 offers aninfinite variety of bandwidths that is just not possible by any other means.
 

CODE30 does not use an 'off the shelf' DSP card quite simplybecause DSP Cards require one to 'download' the software into their onboardprocessor's memory. To adjust the centre frequency by 10 Hz or alter theBaud Speed, or even the Shift settings would require one to download anew set of software into the DSP card and start all over again. But inthe meantime you have lost the incoming signal whilst trying to set upthe card!
 

Commercially available DSP Cards do work very well, of that there isno doubt. This is not so much because of the hardware itself, but becauseof the special software which can set up good filters and demodulators,specially tailored to HF keying systems. CODE30 is a DSP packageexcept we have effectively separated the hardware and software. The hardwareremains as a simple A-D convertor card in a spare 8 bit PC Expansion Slotand the software is written to run under DOS rather than an onboard Motorolaprocessor chip! Because the DSP software is interwoven with the CODE3 analysisand decoding software, any software settings changed are performed seamlessly,without any loss of incoming data in a matter of milliseconds!