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參數(shù)資料
| 型號(hào)： | AD6421AST |
| 廠(chǎng)商： | ANALOG DEVICES INC |
| 元件分類(lèi)： | 通信及網(wǎng)絡(luò) |
| 英文描述： | GSM/DCS1800/PCS1900 Baseband Processing Chipset |
| 中文描述： | SPECIALTY TELECOM CIRCUIT, PQFP64 |
| 封裝： | LOW PROFILE, PLASTIC, TQFP-64 |
| 文件頁(yè)數(shù)： | 3/8頁(yè) |
| 文件大?。?/td> | 66K |
| 代理商： | AD6421AST |
AD20msp415
–3–
REV. 0
AUX ILIARY SY ST E M FUNCT IONS
T he GSMP and the VBC perform a number of auxiliary func-
tions that are essential to build a complete mobile radio.
A general radio section constitutes the three functions of trans-
mitter, receiver and synthesizer. Figure 2 shows how the baseband
chipset interfaces to a typical radio architecture. T he transmitter
is fed with baseband analog I and Q signals from the VBC 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. T he 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 VBC.
T he three auxiliary functions, AGC, AFC and Power Ramping
are included to interface to the radio section.
Power Ramp E nvelope
T o meet the spectral and time-domain specifications of the
transmitted output signal, the burst has to follow a specified
power envelope. T he envelope for the power profile originates in
the GSMP as a set of coefficients, down-loaded and stored in
the VBC. T his envelope profile is fed to the RAMP DAC on the
VBC with each burst. T he analog output is fed into the RF
power amplifier, controlling the power profile and absolute level
of the transmitted data. T he power control loop of the power
amplifier can also feedback an error control signal that indicates
whether the output functions are out of specification and the
radio can be switched off accordingly.
Automatic Gain Control (AGC)
T he mobile radio has to cope with a wide range of input signal
levels. T he major part of the overall gain is provided in the IF
amplifier. T he incoming signal level is analyzed in the GSMP
and a digital gain control signal is sent to the VBC. T he AGC
DAC generates the appropriate analog control signal for the IF
amplifier.
Automatic Frequency Control (AFC)
T he mobile radio tracks the master clock provided by the base
station to compensate for temperature/frequency drifts in the
crystal oscillator. Drift of the crystal oscillator over time and
temperature has to be compensated as well as frequency shifts
due to the Doppler effect in the case of a moving mobile radio.
T he received signal is analyzed in the GSMP and a digital con-
trol signal is generated. T his signal is sent to the AFC DAC in
the VBC to control the voltage controlled, temperature compen-
sated crystal oscillator (VCT CX O).
Synthesizer Control
T he GSMP and the respective parts of the Layer 1 software
control the overall timing and frequency generation of the radio
subsystem. T his includes control signals for two synthesizers,
power-down control signals and power amplifier monitor sig-
nals. Detailed information can be found in the AD6422 data
sheet.
SYNTHESIZERS
RADIO
SUBSYSTEM
CONTROL
AGC
AFC
CLOCK
PAERROR
AGC DAC
I
Q
Q
GSMP
BASEBAND/AUXILIARY SECTION OF VBC
DIDIGITAL FIR FILTER
GSMSK
MODULATOR
BURST
STORE
PA
IF
Tx DAC
Tx DAC
RAMP DAC
AFC DAC
SUB DAC
DIGITAL FIR FILTER
SERIAL
BASEBAND
PORT
SERIAL
AUXILIARY
PORT
RAMP RAM
RAMP CONTROL
Rx ADC
Rx ADC
13MHz
VCTCXO
Figure 2. Control of Radio Subsystem
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PDF描述 |
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| AD215 | Circular Connector; MIL SPEC:MIL-DTL-38999 Series I; Body Material:Metal; Series:LJT; No. of Contacts:39; Connector Shell Size:21; Connecting Termination:Crimp; Circular Shell Style:Wall Mount Receptacle; Body Style:Straight RoHS Compliant: No |
| AD215AY | Circular Connector; No. of Contacts:41; Series:LJTPQ00R; Body Material:Aluminum; Connecting Termination:Crimp; Connector Shell Size:21; Circular Contact Gender:Pin; Circular Shell Style:Wall Mount Receptacle |
| AD215BY | Circular Connector; No. of Contacts:41; Series:LJTPQ00R; Body Material:Aluminum; Connecting Termination:Crimp; Connector Shell Size:21; Circular Contact Gender:Socket; Circular Shell Style:Wall Mount Receptacle |
| AD22001 | Circular Connector; MIL SPEC:MIL-DTL-38999 Series I; Body Material:Metal; Series:LJT; No. of Contacts:4; Connector Shell Size:21; Connecting Termination:Crimp; Circular Shell Style:Wall Mount Receptacle; Body Style:Straight RoHS Compliant: No |
| AD22001N | Circular Connector; No. of Contacts:14; Series:LJTPQ00R; Body Material:Aluminum; Connecting Termination:Crimp; Connector Shell Size:23; Circular Contact Gender:Pin; Circular Shell Style:Wall Mount Receptacle |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| AD6422AST | 制造商:AD 制造商全稱(chēng):Analog Devices 功能描述:GSM/DCS1800/PCS1900 Baseband Processing Chipset |
| AD6423 | 制造商:AD 制造商全稱(chēng):Analog Devices 功能描述:GSM/DCS1800/PCS1900 Baseband Processing Chipset |
| AD6426 | 制造商:AD 制造商全稱(chēng):Analog Devices 功能描述:Enhanced GSM Processor |
| AD6426XB | 制造商:AD 制造商全稱(chēng):Analog Devices 功能描述:Enhanced GSM Processor |
| AD6426XST | 制造商:AD 制造商全稱(chēng):Analog Devices 功能描述:Enhanced GSM Processor |
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