Detect IR Khz with a phototransistor

Hi, I'd like to build a "learning" infrared remote that is able to detect also the frequency of the original remote that I use as source to copy. Is it possible to do this with an IR phototransistor?

I need to do this because some remotes I tested are not working at 38Khz that is (more or less) the standard frequency.

I think with highly optimized code it might be possible to capture a digital signal of 38kHz. But you need an example, it will be very hard to make yourself.
You better try a few different IR receiver modules for 36, 38, and 40kHz.

Or do you only want to know the frequency ? That is easy, as long as it is a good digital signal. So you have to amplify the signal with a transistor or opamp, perhaps you need some kind of automatic gain. Use this frequency library : FreqMeasure Library, for Measuring Frequencies in the 0.1 to 1000 Hz range, or RPM Tachometer Applications