Solid State Supplies has announced a low-cost baseband processor that combines analogue and digital PMR processing in a single chip. The CMX8341 is designed for license-free digital PMR (dPMR) radios and implements a half-duplex dPMR air interface together with physical, data link and control layers, an embedded low bit-rate vocoder that requires no licence or royalties, and a soft-decision 4FSK modem. Its high level of functional integration, small size and low power consumption enable the design of compact, economical radios with extended battery life.
The CMX8341, combined with a suitable host and a limiter/discriminator-based RF transceiver, creates a radio confirming to ETSI standard TS 102 490. The processor manages voice and data systems autonomously, including the vocoder. This minimises microcontroller interactions and power consumption.
Uploading a CML data file during device initialisation configures the on-chip sub-system. The file, called Function Image, defines the device’s function and feature set.
It can be loaded automatically from an external serial memory or host microcontroller over the built-in C-BUS serial interface. The CMX8341 is software upgradable in the field with later releases of the appropriate Function Image.
Other features include two auxiliary on-chip ADCs with four selectable inputs and four auxiliary DAC interfaces.