double-polarity pulse-amplitude modulation

double-polarity pulse-amplitude modulation

[¦dəb·əl pə′lar·əd·ē ′pəls ¦am·plə‚tüd ‚mäj·ə′lā·shən] (communications) Pulse-amplitude modulation employing pulses of positive and negative polarity, the average value being equal to zero. Also known as bidirectional pulse-amplitude modulation.