Converting Heidenhain Scale to sq wave

I have a Heidenhain LS 603 glass scale that has a sinewave output.
The manual states that the pickups are silicon solar cells in push-
pull arrangement, 16 microamp peak to peak (pp). The reference
pulse is 8 microamp (pp).

Question: Has anyone converted this signal to 5 volt TTL levels?
If so please share the circuit diagram with me. If not (after I
reinvent the wheel) I will follow up with a future post and let you
all know what I found out.

Thanks
Brian