| ## PPM (Program Meter)
In the example on the left: A 2-channel Stereo PPM with analog DIN scale In the example on the right: A 5.1 Surround PPM with TruePeak scale and switched on Loudness bargraphs (licence SW20002 required) Move the mouse accross the display elements to get the corresponding descriptions.
The PPM or Program Meter provides vertical or horizontal bargraph displays for the individual channels of the active signal source. Depending on the activated licences, the signal level, the loudness or a combination of both are displayed for each channel. Using the Program Meter, please ensure that the levels and loudness values of the individual channels correspond to the requirements defined for the audio program measured. The signal levels for each channel, displayed in yellow, can be presented as Quasi-Peakmeter (PPM), using one of the common scales such as DIN, British or Nordic, or with the newly developed True Peak scale conforming to the most recent standards. True Peak measurements have been introduced to make sure that high-level audio signals cannot produce unwanted artifacts even when processing them in a codec for data reduction, in a sample rate converter or a D/A converter. For codec processing, the EBU R128 recommends a maximum level of -3 dBTP. For all other applications, it recommends a maximum level of -1 dBTP. The loudness bargraphs, displayed in cyan in the factory presets, show the momentary loudness values for each channel using an integration time of 400 ms.