Hi Nimish The katADC is a bit different from the iADC in that it has some RF components before the ADC.
The input to the ADC can be terminated to 50Ohms via an RF switch. The en0 and en1 control this (pulling this low terminates the input). There is a fixed 20dB amplifier before each ADC input. There is a programmable attenuator in front of each ADC input. The attenuation is programmable from 0 dB to 31.5 dB in 0.5 dB steps. atten0 and atten1 control this for each ADC (5 integer bits and 1 fractional bit). The katADC is tuned to toggle 3 or 4 bits with an input of -27dBm and 0 dB total gain. Because of the 20dB amplifier, care should be taken. The way things are set up in the yellow block (take a look under the mask if interested) is that, directly after ADC configuration, whatever configuration is specified on these ports is loaded. This allows a setting to be static, or configurable via a software register. Any change on these ports causes the new configuration to be loaded automatically. The yellow block does not simulate the action of the RF switch, amplifier or attenuator. Regards Andrew On Thu, 2012-03-08 at 11:24 -0500, Nimish Sane wrote: > Hi all, > > > Is there any documentation/memo on how to use the KatADC yellow block. > In particular, I need to know how to use the variable attenuation > feature (inputs atten*, en*). The documentation here — > https://casper.berkeley.edu/wiki/KatADC — mentions about a 20dB Gain > Block (50.0MHz - 850.0MHz), and 0dB to 31.5dB Variable Attenuator > (controllable in 0.5dB steps). It would be nice to know if someone has > already figured out how to do it. > > > I believe there is no KatADC tutorial. Does anyone have a model file > that he/she can share? > > > Also, what should be the power level of the analog signal into the > KatADC? > > > Thanks, > > > Nimish
