I decided to write a simple spreadsheet to calculate the effect of resistor match on the common mode rejection ratio of simple 4 resistor differential amps.
THAT1240, 1243 and 1246 Block Diagram
CMRR Calculator Screen Capture
CMRR Calculator Spreadsheet: https://www.ka-electronics.com/Calculat ... r-beta.xls (xls 15K)
Simply enter the value of R1, R2 and the tolerance. I used the formula found here: http://www.eetimes.com/design/industria ... -Rejection
There's also a THAT1510/1512 gain resistor calculator here: https://www.proaudiodesignforum.com/for ... 1160#p1160
CMRR Calculator Beta
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