Analog Cellular Tutorial


AMPS/(E)TACS AND CDPD
Although the AMPS/(E)TACS analog cellular market is now in a stage of maturity, price erosion has led to rapid growth and a transformation from a business only to a mass consumer market. This growth continues not only in the US and UK (where the stand ards originated) but also in mainland Europe, Asia and Latin America. Interest in wireless data communications is also fuelling growth of the related Cellular Digital Packet Data (CDPD) standard.

For manufacturers facing shorter product life cycles, rapidly decreasing market prices and faster times-to-market, our system solutions present a unique opportunity. We offer a wide variety of solutions - from 3 V ICs to complete turnkey modules and softw are - to address different customer needs. A worldwide network of application support centres is equipped to provide valuable assistance at all stages of the development process, from initial design through qualification and final production.

Current AMPS/(E)TACS and CDPD chipset
Our current chipset (see Fig.8) uses 3 V technology to improve power consumption and standby and talk time in today's handheld phones. Evaluation kits are available for AMPS (OM4753), and will shortly be available for (E)TACS (OM4751) and AMPS/CDPD (OM150 01) standards. The AMPS/(E)TACS kits include a fully functional target system: handset, LCD, keypad, three evaluation boards (baseband board, RF transceiver board, software emulation board) and object code.

The AMPS/CDPD kit contains a multilayer test board, which integrates RF and baseband functions, and demonstration software.

RF Transceiver
The RF transceiver is composed of three low voltage, high performance ICs. The SA601 RF front end incorporates a low noise amplifier (LNA) and downconvert mixer to translate the incoming RF signal to the first IF. The SA606 FM IF further downconverts and demodulates the 1st IF signal to provide the audio/data and RSSI signals. The UMA1015 dual frequency synthesizer locks the receive and transmit VCOs. These three ICs typically draw a total of 20 mA or less from a 2.7 to 5.5 V supply.

Our BGY series of power modules provide a complete, integrated solution for all power classes of AMPS/(E)TACS and CDPD products.

Baseband Section
The AMPS/(E)TACS baseband solution handles all audio and data processing, control and memory functions.

The SA5752, SA5753 audio processors and TDA7050 audio amplifier provide companding, VOX, filtering, amplification and control functions needed to meet AMPS and (E)TACS system requirements. The UMA1000LT data processor incorporates all of the necessary dat a transceiving, processing and SAT functions. The P83CL580 8-bit microcontroller, PCF8582T EEPROM and PSD312L EPROM provide the control and memory for the entire handset.

Module solutions for AMPS/(E)TACS and CDPD
In addition to individual ICs, we also offer complete RF and baseband modules. Samples of a hybrid baseband module for low-voltage phones are now available (OM5300). It combines a microcontroller (8-bit P83CL580), data processor (UMA1000L), audio processo rs (SA5752/53), audio amplifier (TDA7050), EEPROM, discretes and external program memory. This module implements full AMPS/(E)TACS baseband functionality (see Fig.9). (E)TACS RF, AMPS RF and CDPD modules are in development.

Software
A demonstration software package is available (OM4752), based on the PL/M51 language. Together with the hardware evaluation kits, customers can use this software to evaluate AMPS/(E)TACS protocol and operation. The software controls the transmit, receive and man-machine interface (MMI) portions of the system.

Soon to be available is our protocol software running under a real-time operating system. With its real-time kernel, the software is event-driven, enabling the system controller to power down quickly when idle. As this protocol software is being developed with our module-set for official approval (CTIA/FCC/BABT), you'll be able to purchase a qualified software package.

The software, supplied as object code, will have standardized MMI and hardware-platform interfaces. This enables easy customization of the MMI and hardware using the C language.