True peak programme meter.

These devices use peak programme meters instead of VU meters, which gives the reading a different meaning.

Programme level is often measured using a peak programme meter or a VU meter.

A peak programme meter (PPM) is an instrument used in professional audio for indicating the level of an audio signal.

In about 1936 and 1937, German broadcasters developed a peak programme meter which used a mirror galvanometer known as a 'lichtzeiger' (light pointer) for the display.

The term Peak Programme Meter usually refers to these IEC-specified types and similar designs.

Peak programme meter (A quasi-peak meter originally developed by the BBC)

The PPM or peak programme meter used to measure programme levels is actually a quasi-peak reading meter, again with precisely defined dynamics.

BBC Research & Development has made major contributions to broadcast technology, carrying out original research in many areas, and developing items like the peak programme meter (PPM) which became the basis for many world standards.

Traditional methods of measuring signal levels such as the Peak programme meter, and VU meter do not give the subjectively valid measure of loudness which many would argue is needed to optimise the listening experience when changing channels or swapping disks.