Hi,
Yesterday, N9DG wrote, in part:
"I was then immediately thrown into a conundrum pondering that
the lowly 14Khz "audio" IF as being capable of "RF" speech
processing, .... I'm sooooo confoozed."
Well, audio frequency energy travels via air compression/
rarifications. IF frequency energy travels via electromagnetic
waves/currents which can be rf processed, digitally processed, etc.
Don't confuse audio and rf energies, hi.
There is no particular advantage to going to higher IFDSP frequencies,
unless you could go all the way to 100 kHz or higher. Unfortunately,
there are no available A/D:DSP components operating up there;
that is, no 24 bit, 100+kHz A/D nor 32 bit SHARC DSP chips
at 100+kHz, at least that I am aware about. Advise if such
chips are, in fact, on the market and for what price, hi.
Well, there is a chip set that operates even higher, but the
chips alone are priced in the $2000 area! A bit high even for
a high end amateur rig. BTW, the Icom 756ProII uses a 36kHz
IF A/D+DSP chip set; however, II's performance specs do
not reach that claimed for the Orion (103 dB IMD even down to
a 3 or 4 kHz signal pair spacing) with +25 dBm IP3 and +78 dBm
for IP2.
Note that the Ten Tec RX-340 rcvr has a spec of +30 dBm for IP3,
typical, and +25dBm minimum (but only +75 dBm IP2). The final
IF to DSP frequency in the 340 is at 16 2/3 kHz.
73, Jim KH7M
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