CML’s current IC product
portfolio features two digital PMR/LMR specific circuits
aimed at the digital radio markets: a digital radio processor
and a range of vocoder ICs
The CMX7141 Digital PMR/LMR Processor
A low-power digital radio processor IC built upon CML’s FirmASIC® technology
this product, offers a wide range of flexible features, including: analogue
and digital Rx and Tx signal interfaces and a modem function to address the
specification of the required radio ‘data’ system. In addition, the chip
offers a series of auxiliary on-chip ADCs, DACs and synthesised clock output
circuits for peripheral monitoring, control and timing as well as direct
vocoder connectivity, management and control.
Configuration of this FirmASIC® based product to any digital radio specification
is by the loading of a Function ImageTM file into the IC upon power-up. Function
ImageTM files are available from the Technical Portal area of this website.
The major amount of control and digital PMR data handling, including the air
interface protocols, is carried out on-chip, reducing the computational load
on the host thus allowing the use of a lower-power, lower cost host controller.
For use in digital, analogue and mixed-mode equipments, the CMX7141 has the
ability to reconfigure to a full feature (voice signalling and data) analogue
radio, quickly in the field, by the loading of a different Function ImageTM.
The CMX6x8 Family
of RALCWI Vocoder ICs
A family of flexible, high performance RALCWI vocoders (CMX608, CMX618 and
CMX638) for use in many wireless and wireline voice applications where voice
‘data’ is required. With selectable bit rate modes and an FEC function, these
ICs offer near toll-quality voice (Mean Opinion Score (MOS) is 3.5 - 3.6) at
extremely low bit rates.
Robust Advanced Low Complexity Waveform Interpolation (RALCWI) technology uses
proprietary signal decomposition and parameter-encoding methods, which ensure
optimum recovered speech-quality at high compression and low bit rates.
These products, with their low-power requirements, offer versatile encode and
decode facilities with the ability to operate to externally-generated ‘soft-decision’
FEC inputs.
Added to this is a range of auxiliary functions: Voice Activity Detection,
Comfort Noise Generation and DTMF and single-tone detect and regeneration.
Provision is made, on-chip, for operation in digital radio repeaters by using
the extracted Rx FEC at the repeater to correct any errors in the voice-data
before retransmitting (repeating) with a new FEC.
The CMX618 and CMX638s’ integral audio codec removes the need for an external
voice codec whilst providing variable gain earphone and loudspeaker interfaces,
ADC and DAC voice-data and data-voice converters with high-order 4kHz channel
input and output digital filters. All vocoder ICs are equipped enable a wide
range of other external codecs to be used.
These vocoder ICs are free from any licence
and royalty costs and comfortably meet the requirements of many high-performance
audio applications.
