A Frequency-Shift-Keying Transceiver for Bio-Medical Signals
Date Issued
2006
Date
2006
Author(s)
Chou, Hung-Ta
DOI
zh-TW
Abstract
Wireless technique has greatly improved in recent years. Applications in many different field arise quickly. Biomedical-signal wireless sensor system is one of the hottest research targets. The objective of this thesis is to design a wireless interface suitable for biomedical signals. The requirements of such a interface are low power consumption、medium transmission speed and high precision. Frequency-shift-keying fits in with these requirements and is adopted.
A fractional-N type phase-locked loop is used as the modulator. It has the advantages of convenience to change the frequency and high precision. Fractional-N architecture allows the lock speed、loop bandwidth and frequency resolution to be optimized at the same time. A delta-sigma modulator is also used to reduce noise.
The receiver adopts direct conversion topology. Low noise amplifier enhances the weak received signal and a Gilbert mixer down-converts it to baseband by mixing it with the local oscillator signal. A limiting amplifier limits the down-converted signal to rail-to-rail level assembling the waveform of a square wave witch can be view as digital pulses. A counter-based digital demodulator extracts the data.
Subjects
頻移鍵入
收發機
生醫訊號
Frequency-Shift-Keying
Transceiver
Bio-Medical
Type
thesis
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