'
请问老大，如何进补才能将746补成pro的，或者说pro的多了些什么东西！
'
最重要的区别就是加入了中频dsp。中频dsp可不是个选件，746pro在if电路上作了改进。
由于它的if dsp功能非常强大，可以用数字滤波功能直接取代晶体滤波器，
所以在电路上去掉了可选的晶体滤波器。
个人以为746再补上ssb和cw的窄带晶体滤波器，与746pro相比，性能是可以接受的。
但如果你不做dx，就无进补之需了。
here are some features that the ic-746-pro has over
the ic-746:
+ 32bit dsp with 24bit adc
+ selectable digital filters (50+)
+ sharp or soft filtering (via dsp)
+ digital tpbt
+ manual digital notch filter (in addition to anf)
+ twinned digital apf (great for rtty?)
+ dsp based rtty decoder
+ adjustable digital noise blanker
+ digital tx/rx equalization (instead of analog)
+ digital speech compressor (instead of analog)
+ digital voice recorder
you'll notice how prominently the dsp plays in this rig.
one thing the original 746 has over the 746-pro is an
additional if stage, thus its tpbt is actually going
through two offset if filters. the 746-pro achieves its
tpbt via the dsp. its argued that the dsp filtering more
than makes up for the lack of the extra filter and is
more programmable/flexible. it's counter argued that dsp
filtering is not as effective as traditional if filtering
(the 746-pro instruction manual even eludes to this) and
that insufficient filtering early on overtaxes the dsp.
both are excellent rigs and only time will tell just
how effective dsp really is. perhaps someday icom will
make a rig with both.
