FDM DEMULTIPLEXER for Audio signal

[Md. Sarwar Jahan Sabuj]

I have designed a FDM Demultiplexer using IC 1496. I take the multiplied output from pin 12. Then use low pass filter using 100nF capacitor,1kohm resistor,10nF capacitor and ua 741 to pass frequency upto 15Khz for message signal. But i get the output with huge noise. The total circuit is implemented on breadboard. So what can i do in this case?

 

[jiripolivka]

Please start with 12 V power line blocking capacitors. 100 nF is very low, connect 100 uF in parallel. Check the input signal by an oscilloscope, noise may come from the source.

 

[crutschow]

What is the FDM frequency?

 

[Md. Sarwar Jahan Sabuj]

What is the FDM frequency?

This is the mixture of 3 modulated signal with 3 different carrier frequency(100,200,300Khz). These all come in a single channel. Mentionable, lab purpose only.