DVSI debuts new half-rate vocoder
Digital Voice Systems Inc. has introduced a new Half-Rate Vocoder, which represents an advancement in high-performance voice compression for mobile communications.
DVSI’s new Half-Rate Vocoder operates at 2’450 bps and includes integrated forward error correction to raise the total channel rate to 3,600 bps.
This represents an improvement in channel capacity over vocoders used in wireless communication systems.
In addition to more capacity, the new Half-Rate Vocoder provides higher voice quality and better robustness to bit errors as illustrated in the graphic above according to DVSI.
The Half-Rate Vocoder is designed for wireless communication systems, including mobile radio and wireless telephony.
For example, DVSI has proposed standardizing this new Half-Rate Vocoder for APCO Project 25 (P25) land mobile radio equipment to double the number of communication channels available for public safety.
DVSI has designed the 3600 bps Half-Rate Vocoder as an extension to the standard 7,200 bps Full-Rate IMBE Vocoder in use throughout P25.
The IMBE Vocoder also was developed by DVSI and was selected for use in P25 about 10 years ago.
Both the new Half-Rate and the older Full-Rate are based on DVSI’s Multi-Band Excitation (MBE) technology, which codes speech using a set of MBE model parameters for each frame of speech.
However, the new Half-Rate Vocoder incorporates DVSI’s latest technology to obtain excellent performance at half the data rate.
Furthermore, it adds new tone capabilities, soft-decision decoding, and bit stealing for operation at even lower rates (for example, see the 3,300 bps data in the above chart).
The result is that the new Half-Rate Vocoder can both improve system efficiency, by doubling the number of voice channels, and improve overall system performance.
DVSI plans an expanded range of products to support the Half-Rate Vocoder.
Optimized DSP software for the Texas Instruments TMS320C54x is available and versions for other DSP families are planned.
DVSI also is offering its NET-2000-P25 vocoder unit, which serves as Ethernet capable evaluation module that supports both the Half-Rate and Full-Rate Vocoders.
NEC unveils new power amplifier
California Eastern Laboratories has announced the availability of a new three-stage GaAs MMIC Power Amplifier from NEC.
The UPG2118K combines predriver, driver, and output stage in one miniature package and is useable in bands from 800 to 2500 MHz
It’s ideal for use in 915 and 2400 MHz ISM band applications, as well as other Short Range Wireless bands not covered by industry standard MMIC PA designs.
Its versatility also makes it a viable option for standard applications such as Cellular, GSM 900, DCS 1800, PCS 1900, and W-LAN.
The UPG2118K delivers high output power, high gain, and high efficiency.
It’s fabricated using E-mode FET technology, so it requires a single, positive, low voltage power supply.
Performance specs include:
Operation: 800 – 2500 MHz
Output Power: +32 dBm (1.5W) min.
Gain: 44 dB typ at 1.8 GHz
Power Added Efficiency: 42 percent min at 1.8 GHz
Power Requirement: 2.8 – 5.5 V single, positive supply
On-chip active bias helps the UPG2118K maintain a constant bias current over temperature and variations in Vth.
Off-chip matching also allows the designer to take full advantage of the device’s bandwidth flexibility, optimizing performance for a given frequency.
Housed in a miniature 4 mm square 20-pin leadless package, the UPG2118K is in stock and available now from CEL.
RF Micro Devices transceiver earns nod
RF Micro Devices Inc. announced its POLARIS TOTAL RADIO transceiver has achieved Full Type Approval (FTA) with Chi Mei, a leading Taiwanese handset Original Design Manufacturer (ODM).
The POLARIS transceiver is the world’s first fully integrated quad-band transceiver solution and the first solution with a fully integrated digital interface between the handset’s baseband and radio.
This marks the first time FTA has been achieved in a handset using RFMD’s POLARIS TOTAL RADIO transceiver, according to a company press release.
FTA is the official certificate of conformance to GSM/GPRS standards, and all GSM/GPRS handsets must pass FTA before being released to the market.
FTA is the most significant milestone in the certification of GSM/GPRS handsets as it represents the final approval before production shipments begin.
Chi Mei expects to produce GSM/GPRS handsets, modules and PC cards using the POLARIS TOTAL RADIO transceiver for Original Equipment Manufacturers.
Shipments of the transceiver are expected to begin in the December 2003 quarter with mass production volume to commence in the March 2004 quarter.
The POLARIS TOTAL RADIO transceiver is an integrated GSM/GPRS radio transceiver that performs all the functions of the radio section of GSM/GPRS handsets.
The transceiver implements both very low IF (VLIF) and direct conversion receive (DCR) architectures and provides selectable analog and digital I/Q baseband interfaces.
Additionally, POLARIS reduces total component count by integrating voltage control oscillators (VCOs) and loop filters.
The POLARIS transceiver achieves exceptional RF performance particularly in sensitivity and low power consumption by capitalizing on the best combination of semiconductor process technologies.
The POLARIS TOTAL RADIO transceiver is offered with RFMD’s PowerStar power amplifiers — the industry’s leading GSM/GPRS power amplifiers with integrated power control.