Dc Characteristics; Regulators; Control Signals; Functional Description - Nokia NSE-6 SERIES Service Manual

PAMS
Technical Documentation

DC Characteristics

Regulators

Transceiver has got a multi function power management IC, which con-
tains among other functions, also 7 pcs of 2.8 V regulators. All regulators
can be controlled individually with 2.8 V logic directly or through control
register. In GSM direct controls are used to get fast switching, because
regulators are used to enable RF–functions.
Use of the regulators can be seen in the power distribution diagram.
CCONT also provides 1.5 V reference voltage for SUMMA and CRFU1a
( and for DACs and ADCs in COBBA too ).

Control Signals

All control signals are coming from MAD and they are 2.8 V logic signals.

Functional Description

RF architecture has a conventional dual conversion receiver and in trans-
mitter there is a upconversion mixer for the final TX–frequency.
The architecture contains three ICs. Most of the functions are horizontally
and vertically integrated. UHF functions except power amplifier and VCO
are integrated into CRFU_1a, which is a BiCMOS–circuit suitable for
LNA– and mixer–function. Most of the functions are in SUMMA, which
also is a BiCMOS–circuit. SUMMA is a IF–circuit including IQ–modulator
and PLLs for VHF– and UHF–
synthesizers.
Power amplifier is a MOSFET (hybrid) module. It contains three amplifier
stages including input, interstage matchings and output matching net-
work. Also TX gain control circuitis integrated into the module.

Frequency synthesizers

Both VCOs are locked with PLLs into stable frequency source ( see figure
3 ), which is a VCTCXO–module ( voltage controlled temperature com-
pensated crystal oscillator ). VCTCXO is running at 13 MHz. Temperature
effect is controlled with AFC ( automatic frequency control ) voltage,
VCTCXO is locked into frequency of the base station. AFC is generated
by baseband with a 11 bit conventional DAC in COBBA.
UHF PLL is located into SUMMA. There is 64/65 (P/P+1) prescaler, N–
and A–divider, reference divider, phase detector and charge pump for the
external loop filter. UHF local signal is generated by a VCO–module (
VCO = voltage controlled oscillator ) and sample of frequency of VCO is
fed to prescaler. Prescaler is a dual modulus divider. Output of the pres-
caler is fed to N– and A–divider, which produce the input to phase detec-
Original 08/98
NSE–6
System Module
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