We are building a FSK demodulator with the mark & space frequencies being 18KHz & 20KHz respectively. We require an envelope detector for the process, and we have chosen ADL5511 for that. But, according to the guidelines provided in its datasheet, high valued capacitors are required to be connected at the FLT1, FLT2 & FLT3 pins, the values are going up to 0.68uF. Please suggest me whether the device can be used with connecting such capacitors to detect envelope of 18KHz & 20KHz frequency signals.
We are using separate envelope detectors for mark & space frequencies. So, differentiation between the two FSK frequencies is the matter of concern. The concern is, whether the device can be successfully operated with high valued capacitors connected at the FLT1, FLT2 & FLT3 pins, required for detecting envelops corresponding to low carrier frequency input. The maximum carrier frequency expected at input is 20KHz.
Thanks so much!