Apparatus for measuring the characteristics of a wideband electromechanical recording system having a transformer

A monitoring apparatus for measuring a mechanical characteristic of a wideband electromechanical cutterhead in a system for recording signals within a given range of frequencies in a disc master;

• the frequency spectrum of said signals having a region of relatively high energy level, said system including a source for supplying said signals;
• said cutterhead being responsive to said signals for recording representations of said signals in said disc master when relative motion is established therebetween;
• said apparatus comprising:
• equalizer means, connected to said source, for selectively modifying the energy level of said signals;
• said equalizer means being constructed such that the shape of the frequency response characteristic of said equalizer means complements the shape of the frequency response characteristic of said cutterhead so that the combined response of said equalizer means and said cutterhead is relatively uniform over said given range of frequencies;
• means, connected to said equalizer means, for providing signals of a first polarity to a first signal path and for providing signals of a polarity opposite to said first polarity to a second signal path;
• said first signal path including said cutterhead and a sensing capacitor connected in a series arrangement;
• said second signal path including a balancing capacitor and said sensing capacitor connected in a series arrangement;
• said balancing capacitor having a capacitance value such that the potential difference across said sensing capacitor is a substantial representation of the mechanical characteristic of said cutterhead.

A monitoring apparatus for measuring mechanical characteristic of a wideband electromechanical cutterhead in a system for recording signals within a given range of frequencies in a disc master;

• the frequency spectrum of said signals having a region of relatively high energy level, said system including a source for supplying said signals;
• said cutterhead being responsive to said signals for recording representations of said signals in said disc master when relative motion is established therebetween;
• said apparatus comprising:
• means, connected into a feedback loop, for selectively modifying the energy level of said signals, for providing signals of a first polarity to a first signal path and for providing signals of a polarity opposite to said first polarity to a second signal path;
• said feedback loop being constructed such that the mechanical response of said cutterhead is relatively uniform over said given frequency range;
• said first signal path including said cutterhead and a sensing capacitor connected in a series arrangement;
• said second signal path including a balancing capacitor and said sensing capacitor connected in a series arrangement;
• said balancing capacitor having a capacitance value such that the potential difference across said sensing capacitor is a substantial representation of the mechanical characteristic of said cutterhead.