The TRACOR Model 895 Linear Phase/Time Comparator (figures 1-1 and 1-2) is designed to measure the relative phase or time difference between two signals. Because of its resolution and wide range, this instrument can be used for a variety of time and frequency measurements. In its two modes of operation, the Model 895A provides a front panel meter readout of the time difference between the two input signals on full-scale ranges of 0.1, 1.0 or 10 microseconds, or the phase difference between the two input signals on full-scale ranges of 1.0, 10 or 100 cycles. By virtue of its extreme resolution (1 nansecond in the microsecond mode at 0.1 microsecond full scale), the TRACOR Model 895A facilitates rapid, accurate adjustment of high quality frequency standards. When twenty-four hour averaging is employed, resolution of the Model 895A is adequate to allow comparison of atomic frequency standard signals with a resolution of approximately one part in 10¹⁴. Front or back panel Record Outputs may be used for evaluating precision oscillator performance, or as a continuous check of time difference between a clock system and a standard time source. A front panel MONITOR connector provides phase or time difference outputs suitable for display on an oscilloscope. This allows magnification of the Model 895A output and makes possible very rapid adjustments of oscillators.