Biomedical Engineering Reference
In-Depth Information
2.4 GHz ISM
UNII/ISM
802.11a
HiperLAN
802.11 b/g
Bluetooth
GPS DCS/PCS
WIMAX
-41.2 dBm/MHz
1.6
1.9
2.4
3.1
3.5
4.8
5
6
Frequency (GHz)
Fig. 2
Major interferers for the 3-5 GHz impulse radio ultra-wideband (IR-UWB) system
interferers to the 3-5 GHz IR-UWB system are illustrated in Fig.
2
. The 2.4 GHz
industrial science medical (ISM) band is currently adopted by 801.11 b/g WLAN and
Bluetooth. The 5 GHz Unlicensed National Information Infrastructure (UNII)/ISM
band is divided into two, 5.2-5.8 GHz sub-bands. Besides, in-band interferer such
as WiMAX service occupies the 3.4-3.9 GHz bands. Effective suppression of both
in-band/out-of-band interference signals is critical for the deployment of IR-UWB
communication system for practical applications.
In this chapter, an interference robust single-chip IR-UWB transceiver SoC in-
cluding RF transceiver and digital baseband for WBAN applications is presented.
In-band/out-of-band interference suppression functions are incorporated using notch
filter in low noise ampliflier (LNA) matching network and an ED with frequency
conversion characteristics. A low-power pulse synchronization algorithm is imple-
mented in the digital baseband. The proposed IR-UWB system on chip (SoC) has
been successfully applied in a continuous vital signal monitoring system and the
performance is verified with measurement results.
System Architecture
The block diagram of the proposed IR-UWB transceiver SoC is shown in Fig.
3
[
9
].
A fully differential transceiver radio frequency (RF) front-end architecture is
adopted in this design to provide good suppression of common mode noise in power
supply and noise through substrate coupling. It also provides direct connection
to the external differential antenna, without using bulky and lossy balun circuit.
Time-division multiplexing is adopted to activate the TX and RX alternately through
the control of on-chip T/R switch.
On the TX side, a fast startup LC voltage-controlled oscillator (VCO) controlled by
TX data, generates the UWB pulse and then is amplified by a driving amplifier (DA).
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