I need help to understand the limitations of a simple resistors network to sum my two signals as described in the previous links. Indeed, I succesfully implemented this to sum two 3-bits PWM running at 10kHz as a test and I am now wondering what can be the advantages of summing those signals by using an op amp or by using "complex" circuits like the one described in the second part of the first link.
I understand that with the passive resistor summing, I have to be sure my two PWM signals have the same impedance but it should be the case as they come from the same MCU. I also understand that this method will not give the best results in terms of distorsion but as long as I am not using this to carry audio signals or other sensible signals, it should be okay, right ?
Briefly, I'd like to know your opinion on using passive resistors suming to mix let's say two 8-bits PWM signals at around 10 kHz in order to emulate a 16-bits PWM signal and what can be the pros and cons of using another "sophisticated" method. The resulting signal after filtering has low frequency (<1 kHz) but requires good SNR.