PURPOSE: To accurately detect the data existing area of a PCM signal by detecting even and odd number of fields at reproduction, in a PCM device using a VTR for a recording and reproducing system.

CONSTITUTION: An internal horizontal synchronizing signal from a terminal T3 is applied to binary counters 21AW21C and D-FFs 40 and 41 as a clock signal respectively. A program search signal of a field and a clock pulse are respectively applied to terminals T4 and T7. A start pulse at a vertical blanking period is picked up from the output of an NOR gate 26 and an end pulse is picked up from the output of an NAND gate 29. Thus, a pulse indicating even and odd number of fileds is picked up from the output of a D-FF38. As a result, a pulse indicating the data existing area is outputted from the output of a D-FF39. Thus, the existing area of data can accurately be detected without malfunction.