在ISO 14443 Type A 系統中，讀取器利用磁場感應的方式提供被動式標籤能量及接收標籤訊號。但讀取器天線與標籤天線間的互感(Mutual inductance)，會影響其間的通道狀況，導致標籤回應訊號失真。因此如何正確地解調失真的訊號，對於讀取器設計是重要課題。

在本論文中，我們使用軟體定義無線電平台，實現可解讀ISO 14443 Type A標籤訊號之讀取器。該讀取器可控制發射端之功率、載波頻率及讀取器各段指令間的時間差等參數，以驗證各參數對標籤的影響，並可成功讀取標籤辨識碼。

本研究使用軟體模擬與硬體實現方式，驗證以下列三種不同方法，對失真的標籤訊號進行解調的效能分析。一，直接以理想訊號為基底的匹配濾波器解調；二，以失真的標籤回傳訊號為基底的匹配濾波器解調；三，先將失真的標籤回傳訊號經由最小均方（LMS）演算法等化器補償，再以理想訊號為基底的匹配濾波器解調。模擬與實驗結果顯示，在相同訊雜比條件下方法三解調之位元錯誤率優於其他兩種方式。

In an ISO 14443 Type A system,　a reader provides power to a passive tag and receives response signal from the tag via magnetic coupling between the reader antenna and tag antenna. Yet the mutual inductance between the two antennas could affect the communication channel, and result in tag response signal distortion. Hence how to demodulate and decode the distorted signal correctly is an important issue in reader design.

In this thesis, we use a software defined radio (SDR) platform to implement a reader that can read an ISO 14443 Type A tag. The transmitter of the reader can control power, carrier frequency, and time interval between reader commands, and can successfully retrieve the tag ID of the tag.

This work uses both software simulation and hardware implementation to verify the following three kind’s demodulation and decoding methods performance for distorted tag signals. First, the tag signals are demodulated with a match filter set whose bases are ideal signal waveforms. Second, the tag signals are demodulated with a match filter set whose bases are distorted signal waveforms. Third, the tag signals are passing through a LMS equalizer first, and then demodulated with a match filter set whose base are ideal signal waveforms.
Simulation and experimental results show that the third method outperforms the others in terms of bit error rate in the same signal to noise ratio.

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