Designers can develop dual-mode (digital/analog) radios for wearable and personal radio formats operating at up to 2 W and 5 W

By Jean-Jacques DeLisle,
contributing writer

global market for digital mobile radio is rapidly expanding. Increasingly,
designers and engineers are coming up with commercial applications for digital
radio technology; however, analog radio technology is still in use in many
applications. The need for a technology that can easily switch between analog
and digital radio signals for personal wearable radios has prompted the
creation of dual-mode solutions. Voice radio operations are transitioning from
analog to digital signals more and more each day. These new technologies enable
developers to more easily engineer technology that can be useful throughout
this transition by allowing users to easily switch between analog and digital

Microcircuits recently announced a line of products designed to address the
needs of portable radio applications operating at 2 W and 5 W, both short and
medium ranges. Highly integrated solutions such as the SCT9389 include dual-mode
utilization. The SCT9389 is made up of an SCT3268TD digital baseband processor
including an embedded host controller, an RF power amplifier, and an RF receiver
all packed into a relatively small single-form-factor design that measures only
48 × 35 mm.

new design is specifically engineered to meet European standards and utilizes
CML Microcircuits’ direct conversion technology, making switching from analog
to digital signals easy. The device features a fully embedded protocol stack
that includes the physical layer as well as the data link and control layers.
For those engineers who are less familiar with PMR requirements, having a
readily made solution for RF needs can dramatically speed up development time.

SCT9389 supports various formats including analog technologies such as clear
voice, CTCSS, and DCS as well as digital voice (dPMR/DMR — private and group
call), digital data (short message), and digital supplementary service
(dPMR/DMR). This means that the transition from analog to digital information
is fully supported. Another interesting feature of the SCT9389 is its ability
to detect and automatically switch between analog and digital modes as needed.
The technology has been developed for use in small digital radios and wearable
tech that operates at up to 2-W system power.

Microcircuits also released a range of reference designs that provide designers with a turnkey
solution for digital mobile radio design. The reference design includes Gerber
files, bill of materials, firmware, and software needed to develop a
dPMR/DMR/analog mobile radio. It’s available free of charge to qualifying
customers. A design example is the SCT9366D based on the SCT3258TD digital
baseband processor, suitable for devices operating at up to 5-W transmit power.

As the world transitions from analog to digital
radio, the need for technology that can integrate with both will continue to
grow. Solutions like this could be a big step in advancing into the digital age
by allowing designers to comply with rigorous standards and simultaneously be
able to interface with older technology.