| 摘要 |
PURPOSE:To correct easily so as to make recording of video signals performed at specified frequency by visualizing video signals based on a test chart having component of frequency corresponding to reference frequency signals and each based on each reference frequency signal on an oscilloscope. CONSTITUTION:Oscillators 6-8 send out reference frequency signals S1-S3 which are signals of frequency 6MHz, 7.5MHz and proper frequency between 6MHz and 7.5MHz. Out of these frequencies,6.0MHz is standardized as frequency representing sink tip, and 7.5 MHz is standardized as frequency indicating white peak. A switching circuit 9 selects terminals 9a-9d successively by timing signals Ty of a timing circuit 10. Signals selected by the switching circuit 9 are supplied to an FM demodulator 12 through a limiter 11, and after demodulated by the FM demodulator 12, supplied to an oscilloscope 15 through a de-emphasis circuit 13 and an amplifier 14. |
