| 摘要 |
A digital signal source and an analog signal source, such as might be oontained in a video tape cassette, can be discriminated from each other in a video tape recorder by providing only a minimum of electrical contacts. A first contact is connected to voltage source and a fourth contact is connected to ground, while second and third contacts are connected through resistors to the voltage source. The second and third contacts are respectively connected through fixed contacts of two change-over switches to a serial data line and to a serial clock line of a data processing circuit, and those contacts are also respectively connected through the other fixed contacts of the change-over switches to comparing input terminals of a group of comparators. A voltage-dividing circuit formed of resistors is connected to the voltage source and the voltages developed at respective voltage-dividing points are supplied to reference input terminal. of the comparators and output signals from the comparators are supplied to data input terminals of a data processing circuit in the video tape recorder. <IMAGE> |
