EMRFD Message Archive 226

Message Date From Subject
226 2006-12-01 19:11:38 Hari G MC3356 question
  I need some help with MC3356 configuration as used in W7ZOI spectrum analyzer. 
Iam using the same configuration with change in the power supply for the 3140 as 8V and the resistors R320 and R319 as 4k7.
The problem iam facing is with R317, if its 470Ohms the sensitivity is very less when i touch input of the 3356 the o/p voltage is not increasing. 
If R317 is 10K the o/p voltage is always at half level , when i have it as 6k8 its at the minimum and when i touch the input it comes to half the level and when i give an input from the DDS to that its going to max.
I would like to know if this behaviour has got something to do with R317 included in the Opamp gain calculation or its something to do with 3356 internals.      
Best Regards
De Hari