| Summary: | 碩士 === 國立台灣工業技術學院 === 電子工程技術研究所 === 85 === Abstract In this paper, we discuss RF
circuits including frequencysynthesizer and receiver of direct
sequence spread spectrum(DSSS), which are essential parts of a
DSSS system. We set frequency ISMband from 902 MHz to 928MHz.
The frequency band is divided into 10 channels; each channel has
a frequency band of 2.048MHz. We use Philips' dual frequency
synthesizer, UMA1015M, as a frequency synthesizer IC. The
synthesizer IC, voltage-controloscillator and loop filter form a
RF signal generator of frequency synthesizer. The frequency
synthesizer serves as a FM modulation.In addition it serves as a
local oscillator for the receiver. To satisfythe need for
digital communication, we also add Gaussian filter with bit-
period product 0.5. The switching time of this synthesizer is
220us. In receiver, we first arrange power level budget to
estimatereceiver sensitivity. Each sub-circuit of the receiver
is designed properly to meet the power level requirement. We
integrate thefrequency synthesizer and receiver as a system. We
measure thesensitivity, bit error rate and eye diagram of the
system, and findthat the system has a sensitivity -90dBm at bit
error rate 0.001.
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