Welcome in the fascinating world of PSoCs!
It does not sound too difficult, there are plenty of counters and timers availlable within a PSoC5 all equipped with a capture function. The ARM cortex m3 is fast enough to handle interrupts with 1kHz frequency.
Counting the pulse-width of a 1 kHz signal can be done mostly in hardware.
To start with I would suggest you to get hands on an evaluation kit as this secure.cypress.com/. It gives you debug-capabilities as setting breakpoints and inspecting variables. Additionally you need the Creator software that you may download (Free, just registration) from the Cypress website here secure.cypress.com/psoccreator/.
Lastly there is a whole bunch of videos showing how to get acquainted to "Thinking PSoC".
I have seen HW and SW only solutions on the web to do the decode.
Basic info here http://www.irigb.com/IRIGB_standard.html
Timing does not look too critical. Peak detection in PSOC simple as well as
period counting. Maybe even a LUT to control most of the activity. On e
complication is possibilitry there is a need for an AGC loop, but there are
many methods to handle that.