| 摘要 |
PURPOSE:To display the frequency characteristics, by recording a plurality of the reference signals different from frequencies, and comparing the reproduced level with the predetermined reference level. CONSTITUTION:The reference signal, e.g. 500kHz from a reference signal oscillation section 2 is recorded on a magnetic tape 6 with a recording head 5 under AC bias from a bias oscillation section 4 through a recording equalizer 3. The recorded signal is reproduced at a reproducing head 7 and fed to a comparison section 12 via an equalizer 8, sample holding and rectifying circuit 9, AD converter 10. The input and the reference level are compared at the comparison section 12 and the reproduced level is displayed to a display section 11. Similar operation is made to the reference signal in other frequencies, and display elements 111-11n corresponding to each reproduced level are illuminated to display the frequency characteristic graphically. |
