This paper examines the aspects of peak-program metering. One should respect the fact that this level metering system has stood the test of time over the past six decades where specifications have been tightened and its performance defined under the IEC. Yet despite the almost universal acceptance of the PPM in areas such as broadcasting or sound recording, two questions remain to be answered: How can such an instrument operate in a digital recording environment? How to overcome the discrepancy of the PPM readings when it comes to loudness level indication? Results of extensive research suggest that the solution lies in dual mode bar-graph display operation. The main indication, fully compliant to IEC standards, is obtained by means of a light bar along with the familiar scale, whereas the true peak-level indication or loudness level indication is optionally obtained on the same display through the highlighted part of the same light bar but translated in the proposed manner. Practical solution involves true A/D conversion, microprocessor control brings additional features derived from the very nature of this approach and from day-to-day practice.
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