| 摘要 |
PURPOSE:To simplify the structure of a device, and also to make it inexpensive, by superposing a low band signal on a part of a recording video signal, recording it by a magnetic head, reproducing this low band signal by a fixed readout head provided separately, and detecting recording failures. CONSTITUTION:A video signal inputted to a terminal 1 is FM-modulated 3 through a preemphasis circuit 2, is added 5a, 5b to a low band signal from an oscillating circuit 9 which is switched on 10a, 10b for a prescribed period, and is recorded in rotary magnetic heads 8a, 8b. Subsequently, the low band signal is reproduced by a fixed readout head 15 provided on a path of a magnetic tape which is not shown in the figure. When the video signal is not recorded due to failure, an output signal of a detecting circuit 25 omits the low band signal and becomes a low level signal ''0''. Accordingly, a high level signal 1 from an OR circuit 28 corresponding to this period is outputted from an AND circuit 27, and light is emitted 30 by a retrigger monostable multivibrator 29, by which recording failure is known. |
