In an optical signal readout apparatus including a source of laser light, {TAIL ~ a rotary disc record}, {HEAD ~ a photo detector}, and an optical scanner for focusing light from the source onto the record and directing light reflected back from the record onto the photo detector, the improvements characterized by: 
In an optical signal readout apparatus including a source of laser light , { TAIL ~ a rotary disc record } , { HEAD ~ a photo detector } , and an optical scanner for focusing light from the source onto the record and directing light reflected back from the record onto the photo detector , the improvements characterized by :
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH