ADPLP01 ,GSM Baseband Processing ChipsetcharacteristicsThe BBC receives data at 270 kb/s. The on-chip lookup-tableand timing information.RO ..
ADR01AR ,Ultracompact Precision10 V/5 V/2.5 V/3.0 V Voltage ReferencesSpecifications subject to change without notice. No license is granted by implication www.analog.c ..
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ADR01AUJ-R2 ,Ultracompact Precision10 V/5 V/2.5 V/3.0 V Voltage Referencesapplications. Part Number Output Voltage ADR01 10.0 V With an external buffer and a simple resisto ..
ADR01BKSZ-REEL7 , Ultracompact, Precision 10.0 V/5.0 V/2.5 V/3.0 V Voltage References
ADR01BR ,Ultracompact Precision10 V/5 V/2.5 V/3.0 V Voltage ReferencesCharacteristics, Table 2....... 4 Added ADR03...... Universal Changes to Ordering Guide .... 19 Add ..
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ADPLP01
GSM Baseband Processing Chipset
REV.0
GSM
Baseband Processing Chipset
SYSTEM ARCHITECTURE
GENERAL DESCRIPTIONThe Analog Devices GSM baseband processing chipset provides
a competitive solution for GSM based mobile radio systems. It
is designed to be fully integrated, easy to use, and compatible
with a wide range of product solutions. GSM phones using this
chipset and its accompanying Layer 1, 2, 3 software have passed
the European GSM full type approval process.
The chipset consists of three highly integrated, sub-micron, low
power CMOS components that form the core baseband signal
processing of the GSM handset. The system architecture is
designed to be easily integrated into current designs and form
the basis of next generation of designs.
The chipset uses an operating voltage of 2.7V to 3.6V, which
coupled with the extensive power management features,
significantly reduces the drain on battery power and extends the
handset’s talktime and standby time.
CHIPSET COMPONENTS
Algorithm Signal Processor (ASP)The ASP is an application specific variant of the ADSP-2171
standard DSP from Analog Devices. It has been optimized to
meet the cost, size and power consumption requirements of
GSM mobile applications. All necessary memory to run the
GSM specific programs is provided on-chip and with its
FEATURES
Passed European GSM Phase I Type Approval
Complete Baseband Processing Chipset Performs:
Speech Coding/Decoding, According to GSM 06.XX
DTMF and Call Progress Tone Generation
Equalization with 16-State Viterbi, Soft Decision
Channel Coding/Decoding According to GSM 05.03
All ADC and DAC Interface Functions
Includes all Radio, Auxiliary and Voice Interfaces
Support for GSM Data Services
Embedded 16-Bit Microcontroller
Layer 1 Software Provided with Chipset
Full Phase 2 Protocol Stack Software Available
Integrated SIM- and Keyboard Interface
Ultralow Power Design
2.7 V Operating Voltage
Intelligent Power Management Features
Up to 70 Hours Standby Time Achievable
JTAG-Boundary Scan
Full Reference Design Available
Three TQFP Devices, Occupying Less than 12 cm2
APPLICATIONS
GSM/DCS1800 Mobile Radios and PCMCIA Cardspreprogrammed ROM, no user programming is required. The
ASP implements full rate speech transcoding according to GSM
specifications, including Discontinuous Transmission (DTX)
and Comfort Noise Insertion (CNI). A high performance soft-
decision Viterbi equalizer is also implemented in software,
embedded in the ROM.
Physical Layer Processor (PLP)The PLP combines application specific hardware and an
embedded 16-bit microcontroller (Hitachi H8/300H) to
perform channel coding and decoding and execute the protocol
stack and user software. The embedded processor executes the
Layer 1, 2, 3 and user MMI software. The PLP can control all
powerdown functions of the other chips and memory support
components to achieve maximum power savings.
Baseband Converter (BBC)The BBC performs the voiceband and baseband analog-to-
digital and digital-to-analog conversions, interfacing the digital
sections of the chipset to the microphone, loudspeaker and radio
section. In addition, the BBC contains all the auxiliary convert-
ers for burst-ramping, AFC, AGC, battery and temperature
monitoring. The chipset interfaces directly with a variety of
industry standard radio architectures and supplies all the
synthesizer and timing control signals.
AD20msp410
SoftwareThe required Layer 1 software is supplied with the chipset. In
addition, an object code license for Layers 2 and 3 of the
protocol stack is available. This exact package of Layers 1,2,3 of
software, coupled with the AD20msp410 chipset, is today in
phones that have passed European GSM Final Type Approval.
Architecture OverviewA standard GSM Handset can be divided into five functional
areas:Analog and Digital Baseband Processing Subsystem(Voice to Radio)Layer 1 Software (Physical Layer)Protocol Stack Software (Layers 2 and 3)Radio SubsystemUser Interface Software (MMI)
Analog Devices and The Technology Partnership (TTP)
provide a cost effective and proven method of attaining the
baseband processing subsystem and protocol stack software.
This data sheet includes functional descriptions of the baseband
processing subsystem and the Layer 1 software. The Technol-
ogy Partnership can provide licenses to software and reference
designs in all the other areas of a GSM hand-portable terminal.
For detailed information about the individual chipset compo-
nents, please refer to the ADSP-2178 (ASP), AD7015 (BBC)
and ADPLP01 (PLP) data sheets for electrical characteristics
and timing information.
FUNCTIONAL DESCRIPTIONFigure 1 is a functional block diagram of the GSM baseband
processing chipset. The chipset can be viewed as a functional
block that contains a number of discrete functional units. The
electrical and functional interfaces to the rest of the system are
briefly described at the end of this section and described in
detail in the individual data sheets for each component.
Figure 1.Functional Description
UPLINKThe uplink baseband processing functions include the following
operations:
Analog-to-Digital Voice Conversion (BBC)A conventional microphone, connected directly to the BBC,
The analog voice signal is sampled at 8 kHz, producing 13-bit
linear values corresponding to the magnitude of the input. The
resulting data is passed to the ASP through a dedicated serial
port.
Speech Encoding (ASP)The ASP receives the voice data stream from the BBC and
encodes the data from 104 kb/s to 13 kb/s. The algorithm used
is Regular Pulse Excitation, with Long Term Prediction (RPE-
LTP) as specified in the 06-series of GSM recommendations.
The algorithm is tested and proven to be bit-exact against the
GSM test vectors including all VAD/DTX functions. After
encoding the data is transferred to the PLP through a parallel
port in discrete blocks of 260 bits at 20 ms intervals.
Channel Coding (PLP)The information received from the ASP contains data values
and filter coefficients that have different levels of priority. These
are subsequently protected to different levels within the channel
coding. The encode protection process incorporates block
coding and convolutional encoding. In addition to the normal
speech traffic channels, the channel coding function also
supports data transmission at full rate and half rate. After the
interleave process, if necessary, the data is encrypted using the
required A5/1 or A5/2 encryption algorithm. Data is then
formatted into bursts, with the required timing and training
sequences and sent to the BBC through a dedicated serial port.
GMSK Modulation and D/A Conversion (BBC)The BBC receives data at 270 kb/s. The on-chip lookup-table
ROM modulates and spectrally shapes the data being sent. A
pair of 10-bit matched differential DACs convert the modulated
data from the digital domain to the analog domain and pass I
and Q data to the transmit section of the radio subsystem.
DOWNLINKThe downlink baseband processing functions include the
following operations:
Analog-to-Digital Conversion (BBC)The receiver I and Q signals are sampled by a pair of ADCs at
270 kHz. The resulting digital words are transferred to the ASP
through a dedicated receive path serial link and DMA control.
Equalization (ASP)The equalizer recovers and demodulates the received signal and
establishes local timing and frequency references for the mobile
unit. The equalization algorithm is a version of the Maximum
Likelihood Sequence Estimation (MLSE) using the Viterbi
algorithm. Two confidence bits per symbol provide additional
information about the accuracy of each decision to the channel
codec’s convolutional decoder. The equalizer outputs a
sequence of bits including the confidence bits. This data is
transferred to the PLP through a dedicated parallel port on the
ASP. At this point, the training sequence and trailing bits,
contained within the burst, are discarded.
Channel Decoding (PLP)The A5/1 or A5/2 decryption algorithm is used, as required, to
recover the data that is ready for the deinterleave process. The
deinterleave process is an exact inversion of the interleave
process used by the transmit section. Data can pass directly to
decision confidence bits supplied by the equalizer. Once these
decoding functions are complete, digitized voice data is trans-
ferred to the ASP through a parallel port. Error control mecha-
nisms are used to ensure adequate bad frame indication.
Speech Decoding (ASP)Encoded speech data is transferred at 20 ms intervals from the
PLP to the ASP in blocks of 260 bits plus the Bad Frame
Indicator (BFI). The speech decoder supports a Comfort Noise
Insertion (CNI) function that inserts a predefined silence
descriptor into the decoding process. The ASP also implements
control of talker side-tone and short term echo cancellation.
The resulting data, at 104 kb/s, is transferred to the BBC
through a dedicated serial path.
Voice Digital-to-Analog ConversionThe Voice DAC function of the BBC uses a sigma-delta con-
verter to convert and noise shape the signal. The 13-bit linear
values are converted to the analog domain and filtered to avoid
any images. The resulting differential signals can be controlled
in volume and drive directly a small earpiece as well as a
separate auxiliary output.
AUXILIARY SYSTEM FUNCTIONSThe ASP, the PLP and the BBC perform a number of auxiliary
functions which are essential to build a complete mobile radio.
A general radio section constitutes the three functions of
transmitter, receiver and synthesizer. Figure 2 shows how the
baseband chipset interfaces to a typical radio architecture. The
transmitter is fed with baseband analog I and Q signals from the
BBC and upconverted to 900 MHz for GSM applications and
1800 MHz for PCN applications.
A dedicated power amplifier increases the RF-signal to the
required level. The receiver amplifies the antenna signal, down-
converts it to an intermediate frequency (IF) and amplifies it
there again. After second conversion to baseband, the I and Q
components of the signal are fed into the BBC.
The BBC, ASP and PLP provide three auxiliary functions for
interfacing to the radio subsystem. These auxiliary functions
include AGC, AFC and Power Ramping.
Power Ramp Envelope (BBC)To meet the spectral and time-domain specifications of the
transmitted output signal, the burst has to follow a specified
power envelope. The envelope for the power profile originates in
the PLP as a set of coefficients, down-loaded and stored in the
BBC. This envelope profile is sent to one of the auxiliary DACs
on the BBC with each burst. The analog output is fed into the
RF power amplifier, controlling the power profile and absolute
level of the transmitted data.
Automatic Gain Control (AGC)The mobile radio has to cope with a wide range of input signal
levels. The major part of the overall gain is provided in the IF
amplifier. The incoming signal level is analyzed in the ASP and
the PLP and a digital gain control signal is sent to the BBC. A
10-bit auxiliary DAC generates the appropriate analog control
signal for the IF amplifier. Additionally gain control can be
implemented by using two output flags of the ASP.
AD20msp410
Automatic Frequency Control (AFC)The mobile radio has to track precisely the master clock
provided by the base station. Drift of the crystal oscillator over
time and temperature has to be compensated as well as fre-
quency shifts due to the Doppler effect in the case of a moving
mobile radio. The received signal is analyzed in the ASP and the
PLP and a digital control signal is generated. This signal is sent
to the two DACs in the BBC. The 10-bit DAC operates as
coarse and the 8-bit DAC as fine adjust. The weighting of the
DACs is such, that both DACs yield a combined resolution of
13 bits. The combined analog output signal is used to control
the voltage controlled, temperature compensated crystal
oscillator (VCTCXO).
Synthesizer ControlThe PLP and the respective parts of the Layer 1 software
control the overall timing and frequency generation of the radio
subsystem. This includes control signals for up to two synthesiz-
ers, powerdown control signals and power amplifier monitor
signals. Detailed information can be found in the ADPLP01
data sheet.
Generation of Auxiliary Audio SignalsUnder control of Layer 1 the ASP can generate a variety of fixed
and user-programmable tones. This includes all standard
DTMF and Call Progress tones as well as user defined tones.
The tone structure can consist of up to four frequency compo-
nents with individual durations.
The ASP also generates Talker Sidetone as specified in the
GSM recommendations. In comparison to traditional hardware
implementations, this software implementation provides manu-
facturing flexibility over a wide range of speaker/microphone
sensitivities.
Figure 3.Audio-/Auxiliary Section of AD7015
Figure 3 shows the audio section and the auxiliary ADC of the
BBC. Input signals can come from either a directly connected
microphone or from a remote microphone in a car kit. Input
gain can be set to 0 dB or +26 dB. The output signal can be
directly connected to a small earpiece and, for further amplifica-
tion, to an external car-kit. Two output-PGAs can be pro-
grammed for –15 dB or +6 dB.
DATA SERVICESData Services is considered to be an essential feature for GSM
terminals and the AD20msp410 chipset is designed to provide
flexible and low cost implementation of Data Services supported
via the GSM air interface.
Figure 4.Implementation of Data Services
The selected system architecture shown in Figure 4 provides for
minimum terminal Bill of Materials, the lowest possible number
of interconnection points and the lowest power consumption
when running speech traffic only. However, the chipset provides
full channel coding and decoding for all Data Services. Parity
and convolutional encoding and interleaving for TCH/F9.6,
TCH/F4.8 and TCH/F2.4 are implemented in the PLP.
The interface to the chipset is a user-configurable, 3-wire serial
interface supplying V110 data packets as defined in GSM 05.03,
combined with protocol information and control to the Applica-
tion Layer. External to the terminal is the Data Terminal
Adapter (DTA) which runs the Data Services Software. Included
in the DTA are the rate adaptation functions and the Data
Services application. The Command Interpreter resident on the
mobile supports a serial interface protocol with the DTA via
both traffic data and control information are communicated.
The Technology Partnership can provide all requisite Data
Services Software.
SOFTWARE IMPLEMENTATIONSA full implementation of the GSM Layer 1 functionality is
supplied as an object code module, for execution on the
controller, embedded in the PLP. Functions performed by this
software include:Initial scan of GSM band and selection of strongest thirty
channels as required by 03.22 and 05.08Mobile oscillator adjustment, timing synchronization and
BCCH decoding from serving cell (camping-on)Base station frequency and timing measurements and BSIC
extraction from neighbor cells under control of Layer 3Frequency hopping according to 05.02Full implementation of discontinuous reception (DRX) and
transmission (DTX)
Analog Voice Interface to BBCThe analog voice interface to the BBC is specified in the
AD7015 data sheet. Several design examples are given for
single-ended or differential inputs or outputs. A voltage
reference for biasing the microphone signal is provided on the
BBC. The analog output of the BBC is capable of driving an
earpiece directly with and impedance of 150 Ω. For optional
use of a separate external microphone and power amplifier, a set
of auxiliary inputs/outputs is provided.
Radio Interface to BBC and PLPThe analog interface between the BBC and the radio subsystem
consists of differential inputs and outputs for the I and Q parts
of the signal and three analog control signals for AFC, AGC and
transmit ramp envelope. Details of these signals are specified in
the AD7015 data sheet. The digital interface between the PLP
and the radio subsystem consists of a serial port for communi-
cating with the synthesizers and several control signals as
specified in detail in the ADPLP01 data sheet.
Digital SIM Card Interface to PLPThe PLP is designed to interface directly to the SIM. However
interface logic may be necessary to connect the 3V chipset to aV SIM.
Digital Interface to KeypadKeypad interface logic for up to 40 keys is provided on the PLP.
This interface provides keyboard scan for 8 Rows and 4
columns. Additionally an extra pin on the PLP is provided for
the power switch.
Digital Bus Interface to Memory and DisplayExternal RAM and ROM as well as the display controller
interfaces directly to the 21-bit address bus and 16-bit data bus
of the PLP.
Interface to FLASH MemoryThe large FLASH memory can contain all programs for the
embedded Control Processor of the PLP. This includes the
complete GSM protocol software as well as the User Interface
Software. A size of 4 Mbit to 8 Mbit is suggested to accommo-
date all Protocol software plus a typical size of User Interface
Software. Enhanced features, requiring larger memories are
supported easily by the large address space of the embedded
Control Processor. To facilitate production programming and
field upgrades of the FLASH memories, the PLP provides
embedded code to download the software into the FLASH
memory via its standard serial port.
Interface to SRAMBeside the FLASH memory, the Control Processor additionally
supports static RAM to store user defined variables, typically
those used by the Protocol Stack or Application Layer. Standard
SRAMs interface directly to the address and data bus of the
PLP.
Interface to Display ControllerThis interface is achieved through the address and data buses
and associated read and write strobes, as well as a specific
enable signal. An integrated wait state generator helps interface
to a wide range of display controllers. Two pins with PWM
outputs control the intensity of separate backlights for displayFull engineering and test mode supportSupport for all phase 1 and phase 2 handover modesSIM Interface driverMessage interfacing to Layer 3 (Radio Resources Manager)
and Layer 2 (data link layer, both signaling and data)External functions for AGC, AFC and synthesizer setting are
called by Layer 1. These allow the user to configure the
system for a wide range of radio architectures including the
TTP GSM reference radio.The higher layers of the protocol stack also reside on this
embedded processor. A GSM Phase 2 compliant, Layer 2/3
protocol stack is available from The Technology Partnership.
POWER DISSIPATION CONSIDERATIONSIn mobile applications, minimizing the power consumption of
all devices is critical to achieving longer standby and talk times.
In a GSM handset the baseband subsystem dominates the
current consumption of the phone in standby. The design of the
ASP, PLP and BBC includes extensive features to reduce current
consumption and give standby times of up to 70 hours.
All three devices were specifically designed to operate from
2.7V to 3.6V, so facilitating three or four cell NiCad/NiMH or
single-cell Li Ion batteries.
The PLP incorporates intelligent power management, permit-
ting automatic control of power consumption in the PLP and
the peripheral circuitry. Data processing modules are switched
on only when they process data, otherwise they are powered
down.
Additional control signals are provided that enable the Layer 1
software to control the external subsystems, such as the ASP,
BBC, radio and memory components, so that their power is
intelligently switched by the PLP.
Within the ASP the different powerdown modes range from a
simple “wait for interrupt” state to a complete hardware
powerdown, with only leakage currents dissipating power.
In the BBC, the powerdown functions are split separately
between receive, transmit and auxiliary circuits. This provides
optimal analog power performance when operating in different
modes.
INTERFACESFigure 5 shows the chipset’s eight interfaces, which have to be
considered in the design of the complete mobile radio. Some of
these interfaces have to meet GSM specifications, others will be
design specific.Analog Voice Interface to BBCRadio Interface to BBC and PLPDigital SIM Card Interface to PLPDigital Interface to the KeypadDigital Bus Interface from PLP to Memory and DisplayDigital Interface from the PLP to the EEPROMDigital Audio Interface (DAI)
AD20msp410
Digital Audio Interface (DAI)As required by the GSM specifications, a digital audio interface
is provided to allow certain tests of the audio section during type
approval. This interface is provided by the serial bus between
the ASP and the PLP and two additional control signals from
the PLP. A fully functional “DAI Box” needed for the FTA
process may be obtained from Analog Devices upon request.
Digital Interface to the PLP for Data ServicesA conventional H8 serial port combined with a proprietary
protocol is used to interface to an external Data Terminal
Adapter.
Digital Interface from the PLP to the EEPROMThe PLP provides separate pins to interface directly to an
external EEPROM via a serial port. This EEPROM is typically
used for storage of calibration or user variable parameters like
handset identifier (IMEI), language, keypad lock and radio
calibration parameters. A typical size of the EEPROM is 2K × 8
bits, but this depends on the individual design of the handset.
GSM Baseband Processing Key Parts ListTable 1 lists the major hardware components necessary to
complete the GSM baseband processing subsystem. An example
Bill Of Material is available from Analog Devices. A full
reference design is available through Analog Devices/The
Technology Partnership.
Table I.List of Key ComponentsNOTESThese components comprise the AD20msp410 chipset.A size of 4Mbits is recommended to allow storage of all GSM Layer
(1, 2, 3) programs as well as a typical user interface (MMI). Larger
memory can be used to support enhanced user interfaces.Can be omitted if parameters are stored in FLASH memory.
Figure 5.System Interfaces
