[R-390] DSP IF

[Bob Camp]

Hi

Try 4. Keeps tripping the spam filter.

If you go out and buy one of the black box radios you still have the 
problem of what to do about the AGC feed back into the R390. If you are 
after good AM you want to be able to cut back the gain on the front end 
and IF's to keep everything linear.

You can get 16 and 18 bit A/D converters these days that will run up to 
the one or two mega sample range. To do things right at 455KC it would 
be nice to be above a 2 MHz clock rate. In order to get up to around 24 
bits on the converter you are going to have to get down to a 200 KHz 
clock. That would put your final IF at maybe 40 or 50 KHz.

	Take Care!

		Bob Camp
		KB8TQ