Heidenhain Encoder - strange waveform help request

I hooked up my spindle encoder which is a 420 series Heidenhain to my oscilloscope and even though the encoder is listed as a square wave TTL encoder , I saw a sine wave? Upon rotating the encoder shaft the scope showed what looked like a TTL square wave going on inside of a sine wave. I really dont know what to think of it but would like to know if thats normal. If its normal, is there anything special i need to do with my HAL file to deal with the strange waveform or do I just treat it like its a regular square wave signal. Im using a MESA 7I76 and 5125 for the interface.

Thanks

Try here.
www.heidenhain.us › wp-content › uploads › 349529-2H_Rotary_Encoders_en.pdf

Well oscilloscopes tend to work better when you remember to hook up the probe grounds.....hahahaha...problem solved

Good. All I could find was 5Volt supply TTL square wave in a 420 encoder.

i have a liniair scale LS904 ml 370 from heidenhain on me mile machine  
i'm not sure  if the scale is broken or  the input  of the controle unit fails  
how can i find out if the scale work wel  ?
what is de basic set up ?
just power  5vdc  on  pin 3and  4 ?
when i use a scope between ground and  an output  what signal do i have to find  or do i need a pull up or down  resistor  ?
i found  in an old document  somthing like  15microampere on the output  
do someone know how to test the scale  
 

These encoders typically need an interpolator interface card
(EXE series)