Dear Lufuno,

I think you need to specify your signals and their required processing in more details.

If i understood you you want to generate 16 different tones and you want to inject them in form of a combined current in a specimen with an impedance. As for the tone generations you can synthesize these tones using a digital frequency synthesizer.

After generating the 16 tone simultaneously  you can convert them into current sources and sum them by using a summing operational amplifier. The impedenace is put in the feedback path of the summing amplifier. The output voltage on the operational amplifier will be equal to the sum of the 16 currents multiplied by the impedance of the specimen which is the at the same time the feed back impedance.

wish you success

I would like asnswer the question to the point.Take 16 2input AND gates.Connect one inputs all the gates together and connect to a binary(1/0)switch.connect 16 current inputs to 16 gates.Now the binary switch acts as enable/disable swith.I think your purpose is served of applying 16 signals simultaneously(enable/disable).

Dear Abdelhalim Zekry ,

I need to generate 16 signals with difference frequencies all between the frequency range 5KHz and 20KHz. The offset in frequency from one signal to the other is 1KHz.

Dear Lufuno,

There are many methods to generate 16 tone with frequency ranging between 5 and 20 kHz. You can use frequency synthesizers. There are two type of frequency synthesizers; the digital frequency synthesizer and the phase locked loop frequency synthesizer. In the second solutions you can use 16 ton generators having the same reference frequency of a crystal oscillator of 1 HZ  The other solution is to sue the digital synthesizer with the suitable clock frequency and the suitable dividers and a sine wave generating ROM.

Thee is a third solution which is accomplished by using inverse Fourier transform of the signal which is constructed in frequency domain.

wish you success