CML Microcircuits CMX7131 and CMX7141 ICs function image

CML Microcircuits has released a function image for the CMX7131 and CMX7141 ICs supporting the development of NXDN-compatible digital voice radio equipment.

Called NXDN, its common air interface is a joint development between Kenwood and Icom. The equipment supports commercial private land mobile radio to serve light commercial, more demanding business and industry, and public safety applications, even on 6.25 kHz channels.

The technology satisfies the US Federal Communications Commission Part 90 ‘narrowbanding’ requirements and, as of December 2009, 70,000 RF channel licences were approved for NXDN operation.

The CMX7131 and CMX7141 are digital PMR processors built on CML’s FirmASIC technology. The technology enables on-chip subsystems to be configured by a function image, a data file that is uploaded during device initialisation that defines the device’s function and feature set.

This provides the flexibility for the CMX7131 and CMX7141 to support dPMR, DCR and NXDN radios as well as analog two-way radios.

The function image provides a number of features very important to NXDN design, including: a high performance 4FSK data pump supporting soft-decision coding mode (which improves the reliability of the data link) and integrated RRC filters; a high-performance, autonomous AFSD that greatly simplifies host microcontroller development and risk, differentiating between frame sync cases, that can also reduce an NXDN receiver’s average Rx power consumption; a voice codec (ADC and DAC) for microphone/speaker paths to complement an external AMBE-3000 vocoder device and integrated auxiliary functions that reduce total BOM cost and size.