| 摘要 |
PURPOSE:To simplify the checking of each function block, by connecting the output terminal of an A/D converting part to the input terminal of a D/A converting part or connecting the output terminal of a PCM encoder to the input terminal of a PCM decoder. CONSTITUTION:A connecting device J2 is short-circuited, and a connecting device J4 is turned off to check whether the input signal of a terminal A is produced at the output terminals F and G. The normal state is decided for A/D converting parts 1-5 and D/A converting parts 9-13 when an output is obtained. Then the devices J2 and J4 are restored after the checking is over through the device J2, and the device J1 is short-circuited with the device J3 turned off, respectively. Thus the output of the input signal is checked. A VTR part 7 is decided defective when an output signal is obtained; while a PCM encoder 6 or a PCM decoder 8 is decided defective when no output is obtained. |
