A new automatic level control for monophonic and stereophonic broadcasting

The need for conserving technical manpower in broadcasting operations has spurred interest in automatic level controlling systems to achieve optimum modulation. A set of operating standards can be established so that any system of level control, manual or automatic, can be appraised. These standards temper technical and aesthetic considerations. An examination of the prior art in the field discloses the shortcomings of systems using the conventional approach and the large degree of compromise that must be accepted by their use. A completely new system, the Audimax, employing simple switching logic has been devised which satisfies the requirements of the operating standards with negligible compromise. This system is described in detail. In order to satisfy the level control problems for stereophonic broadcasting, an adapter is provided for use with two Audimax units which makes the system responsive to the sum of the left and right signals. In this way, the stereophonic perspective is maintained and maximum modulation ensured. Operational experience with the Audimax is described briefly.