Sony IR Remote Carrier Frequency

Say there was no internet, how would I know what the carrier frequency of a Sony infrared remote control was ?

Measure it !

Here is the quick and dirty test fixture:

An IR photodetector diode pulled out of a surplus scale circuit board.  Used the photovoltaic  "generation" capability of the photodiode and measured the voltage output with the scope.  Here is the zoomed out view:

And zooming into 2.5 us per division:

Counting divisions there are 10 in one cycle of the carrier, so 10 x 2.5 us is 25 us.

IR Carrier frequency is 1 / 25 us => 40 kHz

So we need a 40 kHz detector module for the Sony although a 38 kHz module like the one I had been using might work.  Next number: see if I have a 40 kHz module in the junk box or maybe pull it from some defunct Sony product ?  Or buy one (last resort).

Best Regards,
Chuck, WB9KZY
http://wb9kzy.com/ham.htm