Mehr,
Im sure that the conversion could be done. Think about this:
if they can use voltages to convert to frequencies (Voltage controlled oscillators), then it makes sense that you can do the same with current.
its been a long time that i've dealt with op-amps, but I think that there might be...
Why not use another op-amp (Follower circuit)---the feedback path is simply a short circuit, so the output equals the input. Then power +Vcc with 5V, and if the positive portion of the output signal exceeds +Vcc, it will saturate at 5V(Or +Vcc). You can probably do this also with a BJT, and have...
Also, make sure that the input impedance to your amplifier is equal or greater than the output impedance of the function generator. You might need a impedance transformer circuit b4 the amp in case the source (FUN GEN) is getting loaded down. Good luck, and keep me posted.
Thomas
Whats the output impedance of your amplifier? Could it be that its much greater than the 8-ohm dummy load? Perhaps the load is loading down the output of the amplifier, attenuating the useful signal. The scope has a mega-ohmic input impedance, so it would not load down your amp. I suggest that...
Check the quality of the cable between fun gen and your amplifier. Also, is there any DC coming into the amplifier from the generator? Most noise problems come from the source, and amplification just makes it much worse. Also, whats the output impedance of the function generators that you are...