>
> VK6APH: The FST3125 makes a fantastic mixer - with a 3IP of +44dBm from a
> handful of
> bits, it does not make 'a reasonably good mixer' but a 'damn fine mixer',
> bordering on what the military require in terms of performance.
I agree. I tried a mixer a few years back using these devices, after being
sent a RadCom article by G3PQA, and the performance was indeed impressive.
My experience of southern hemisphere operating, however, is that this kind
of 3IP performance is rarely required, simply because of the lower
population densities. If we are talking DSP, it isn't even necessary to use
a mixer, as the 3IP available from a straight A to D converter such as the
Analog Devices 6644 is adequate. Following such an A to D with a digital
downconverter (AD6620) and DSP card, makes a complete digital receiver.
> VK6APH: In terms of system performance, the best you can do is with a
> matched filter
> at the receiver - which is trivial to achieve with a DSP, but virtually
> impossible with conventional
> analogue filters. Please listen to a properly matched DSP filter -
ringing is
> not a problem and if you have subtracted the majority of the noise pulses
> in the pre-filtered bandwidth, then you are in for a very pleasant new
> experience.
>
Phil, how does this subtraction process work? How can the noise pulses be
subtracted without subtracting the wanted signal as well?
73, GReg, ZL3IX
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