tag:blogger.com,1999:blog-7590176649168185428.post1141855698899811162..comments2024-03-29T07:34:28.586-04:00Comments on SolderSmoke Daily News: Digital PotBill Mearahttp://www.blogger.com/profile/07662500663603350847noreply@blogger.comBlogger1125tag:blogger.com,1999:blog-7590176649168185428.post-83390495805898037372018-06-23T08:39:05.918-04:002018-06-23T08:39:05.918-04:00Digital pot is very useful in many cases, but is p...Digital pot is very useful in many cases, but is plenty of problems too to have in mind. <br />The pots I used were Microchip 256 taps. Well, it looks a high resolution, or my be not?. From 256 to 128 are 6 dB and from 128 to 64 6 dB else, and so on. As higer attenuation worst resolution from 8 to 4 6 dB in four steps. Log ancient pots solved the problem but digital ones not or I did not find them.<br />For AGC purpose we have many problems too. Attack time is function of uProcessor speed and programing port speed and length of sample. So, pot AGC is not very nice against classical RF detector AGC but it is still a solution better than manual control. <br />AGC window decission has to be higer than 3dB up to 6dB, so not very good but aceptable.<br />Combining two potentiometers we get a better resolution, final theoretical attenuation 96dB against 48dB only one pot. It is a bit SW complex but not too much.<br />Noise, serial port either I2C or SPI may generate a lot of clics if pot is istalled before a large gain amplifier. Let say 50dB like LM386.Electrónica, comunicaciones y otros menestereshttps://www.blogger.com/profile/06988791369454832311noreply@blogger.com