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NHM–7
System Module & UI
PAMS Technical Documentation
Page 24
Issue 1 10/2001
Nokia Corporation
FM Radio
FM radio circuitry is implemented using highly integrated radio IC,
TEA5757. Only few external components like filters, discriminator and ca-
pacitors are needed.
TEA5757 is an integrated AM/FM stereo radio circuit including digital tun-
ing and control functions. NHM–7 radio is implemented as superhetero-
dyne FM mono receiver. FM stage of the TEA5757 incorporates a tuned
RF stage, a double balanced mixer, one pin oscillator and is designed for
distributed IF ceramic filters. IF frequency is 10.7 MHz.
Channel tuning and other controls are controlled by the MCU. Reference
clock, 75kHz, is generated by the UPP CTSI block.
FM radio circuitry is controlled through serial bus interface by the MCU
SW. TEA5757 informs MCU when channel is tuned by setting
FMTuneX
signal to logic ’0’.
Digital Interface
UPP
TEA5757
FMClk
FMCtrlDa
FMCtrlClk
FMWrEn
FMTuneX
VIO
VIO
WR–EN
BUS–CLK
DATA
XTAL
MO/ST
GenIO(3)
GenIO(27)
GenIO(12)
GenIO(8)
GenIO(11)
NOTE:
FMCtrlClk needs to be set to logic ’1’ when data is not written or
read. This is required for correct operation of the
FMTuneX signal.
FM radio audio & antenna connections
Bottom
Connector
UEM
TEA5757
AFLO
FM_RFI
MIC3
HF
HFCM
XEARP
XEARN
18pF
18pF
72nH
4.7k
Ω
3.9nF
100nF
100k
Ω
1000
Ω
@100MHz
1n
1n
Summary of Contents for NHM-7 series
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