To day i have been a little distracted looking at a op amp as a head amp the CA3140 just to see ,looking into Steve's advice .
I came across this IR transmit extender circuit ,it says its a CA3040 on the schematic but says its a Ca3140 explaining the circuit.
I just used the first op amp part of the circuit .
http://english.cxem.net/infrared/ir8.phpI had my light sensor with a shielded cable at the start to this circuit but results were a lot of noise pick up ,it was much better with my photo diode soldered right to it .
I did do a sweep test see below ,i am not sure yet what to make of it as its a bit weaker to my other tests,but i also did a NBTV transmit test from my led transmitter to this little circuit then again displaying on the lap top,results were distance wise it was not as sensitive to my other circuit but that could be i am just using a clear Led as a photo diode but i could see it had a better or great range of shades of gray to images when at times i manged to get the distance and levels right .
i also tried different op amp in this circuit but was not as good ,that was the Ne 5534 next best but images not as good very dark .
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.