Audio/Signaling Processor Aids Radio Designs

The CMX882 half-duplex audio and signaling processor IC is designed for FRS, PMR446, GMRS, and MURS radios and includes support for GPS. The device operates from a single 2.7V supply and performs voice-band and sub-audio filtering, pre/de-emphasis, compression and expansion, audio routing, and global level setting with single- or two-point modulation in the transmit path. Other features include enhanced CTCSS and DCS encoding and decoding, GPS location data transport via a 1200/ 2400 b/s FFSK/MSK packet data modem with interleaving, FEC, CRC, and data scrambling functions, and more than 99 squelch codes. The signaling format employs both a sub-audio holding tone and in-band (XTC) signaling concurrently. Signaling can be used as on over-air control for features such as voice compression and contact range check. The CMX882 is available in a 28-pin SSOP and TSSOP. For price, contact CML MICROCIRCUITS, Langford Essex, England. +44 1621 875500.