Synth manufacturer founded in 1975 by Wolfgang Palm and operating out of Hamburg, Germany. (The name is an acronym for "Palm Products GmbH", and has nothing to do with Pittsburgh Plate Glass.) Although the company got its start making modular synthesizer equipment, it is best known for its wave scanning designs, particularly the Wave 2 series.
The company was a pioneer in digital synthesis and merging computer interfaces with synths. PPG introduced its first digital synths, the 340/380 series, in 1979. It was used extensively by Thomas Dolby and a few others, but the system was considered difficult to use since much of the processing had to be done "offline", prior to performance time. In order to improve performance capabilities and reduce cost, PPG added analog VCFs and VCAs and simplified the user interfaces, and this became the very successful Wave 2. The design was subsequently improved with the Wave 2.2 and 2.3 (there doesn't seem to have been a 2.1). The computer interfaces which had been deleted to reduce the cost were made available separately as the Waveterm; this system allowed Wave 2.x owners to build their own wavetables from samples or drawn waveforms, and do more sophisticated processing.
In 1985, PPG embarked on a very ambitious project called the Realizer. This was to have been a multi-algorithm synth capable of running several different software applications supporting different methods of synthesis, including virtual analog emulations of synths such as the Minimoog. The Realizer had a large video display surrounded by controls whose panel graphics were to have been coordinated with the video presentation. The project was too big and too ahead of its time; it ate up PPG's cash flow, and the company ran out of money and went under in 1987.