An Ultra-Wideband Sensor Node Development with Dual-Frequency Band for Medical Signal Monitoring - Ultra Wideband Wireless Body Area Networks - page 109

Sampling and data
processing unit

UWB
ANT

IR-UWB
receiver
front end

FPGA ADC

NB ANT

PC

PC

433 MHz ISM
band
transmitter

Fig. 5.26 Basic block diagram of the coordinator node

UWB Rx.
ANT

BPF
(3.5-4.5 GHz)

LNA
+48 dB

LPF
(DC-100 MHz)

Analog Amp.
+10 dB

Mixer

To ADC

VCO (4 GHz)

Fig. 5.27 Block diagram of the IR-UWB front-end

an insertion loss of 0.5 dB. The link budgets of both receiver designs for a trans-
mission distance of 1 m and a PRF of 100 MHz are shown in Table 5.5 .
The time domain waveforms of the received signals after the mixer stage and
after the LPF stage of the receiver (Design 1) for a signal transmitted at a
100 MHz PRF with a transmitter—receiver separation distance of 0.7 m are
shown in Fig. 5.29 . After the analog amplifier, received UWB pulses are detected
using the ADC and the FPGA of the coordinator node. The receive spectrum for
each stage of the UWB receiver front-end is shown in Fig. 5.30 .

5.3.2 Narrow Band Transmitter

TX5000, which is a 433 MHz ISM transmitter module by RFM [ 17 ], is used as the
narrow band transmitter of the coordinator node. This off-the-shelf transmitter
module can transmit data using both OOK and ASK modulation schemes. Narrow