.. 标题：射频信噪比 (SNR) 计算器
.. slug：射频信号噪声比
.. 日期: 2025-12-26 15:00:00 世界标准时间
..标签：网络、计算器、工具
..类别：计算器
..链接：
.. 描述：根据信号和噪声功率计算信噪比 (SNR)（以 dB 为单位）。评估无线链路质量、诊断干扰并预测调制的可实现性。
..类型：文本
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</style>
<div class="calc-container">
<div class="calc-header">
<h2>射频信噪比计算器</h2>
<p>计算信噪比 (SNR) 以确定无线信号质量并预测设备连接问题。</p>
<div class="form-group">
<div class="form-row">
<div class="input-wrapper">
<label class="input-label" for="signal">信号强度（dBm）：</label>
<input class="calc-input" id="signal" placeholder="e.g., -20" type="text" value="-20"/>
</div>
<div class="input-wrapper">
<label class="input-label" for="noise">噪音水平（dBm）：</label>
<input class="calc-input" id="noise" placeholder="e.g., -40" type="text" value="-40"/>
</div>
</div>
<button class="calc-button" onclick="snr()" type="submit">计算信噪比</button>
</div>
<div class="help-text">
<strong>笔记：</strong>SNR 的计算方式为“信号 - 噪声”。值越高表示信号质量越好。为了实现可靠的无线连接，建议最小 SNR 为 15-20 dB。</div>
</div>
<div class="result-section" id="resultSection">
<div class="section-header">
<h3><span class="icon">📊</span>结果</h3>
</div>
<div class="section-content">
<div id="snrResult"></div>
</div>
</div>
<div class="info-section">
<h4>了解信噪比 (SNR)</h4>
<p>信噪比是无线通信中的一个关键指标，用于测量所需信号相对于背景噪声的强度。
            它是通过从信号强度（均以 dBm 为单位）中减去噪声水平来计算的。</p>
<p>
<strong>SNR 质量指南：</strong>
</p>
<table class="snr-table">
<thead>
<tr>
<th>信噪比范围</th>
<th>质量</th>
<th>预期表现</th>
</tr>
</thead>
<tbody>
<tr>
<td>40+分贝</td>
<td>出色的</td>
<td>最大吞吐量，无丢包</td>
</tr>
<tr>
<td>25-40分贝</td>
<td>非常好</td>
<td>高吞吐量，最少的问题</td>
</tr>
<tr>
<td>15-25分贝</td>
<td>好的</td>
<td>连接可靠，吞吐量适中</td>
</tr>
<tr>
<td>10-15分贝</td>
<td>公平的</td>
<td>基本连接，可能丢包</td>
</tr>
<tr>
<td>5-10分贝</td>
<td>贫穷的</td>
<td>连接不稳定，经常掉线</td>
</tr>
<tr>
<td>&lt; 5 分贝</td>
<td>很差</td>
<td>无法使用，连接失败</td>
</tr>
</tbody>
</table>
</div>
</div>
<script>
    function snr() {
        // Set variables from input
        var signal = Number(document.getElementById("signal").value);
        var noise = Number(document.getElementById("noise").value);

        var snr = signal - noise;
        var resultSection = document.getElementById("resultSection");
        var resultDiv = document.getElementById("snrResult");

        // Show result section
        resultSection.classList.add("show");

        // Determine result category and display appropriate message
        if (snr < 0) {
            resultDiv.innerHTML = `
                <div class="result-alert error">
                    <div class="result-icon">🚫</div>
                    <div class="result-content">
                        <div class="result-title">Signal Overpowered by Noise</div>
                        <div class="result-details">
                            The noise level is stronger than the signal. Wireless devices will not function in this area.
                            Consider reducing interference sources or improving signal strength.
                        </div>
                    </div>
                </div>
                <div class="data-row">
                    <div class="data-label">Calculated SNR:</div>
                    <div class="data-value highlight">${snr} dB</div>
                </div>
                <div class="data-row">
                    <div class="data-label">Signal Strength:</div>
                    <div class="data-value">${signal} dBm</div>
                </div>
                <div class="data-row">
                    <div class="data-label">Noise Level:</div>
                    <div class="data-value">${noise} dBm</div>
                </div>
                <div class="data-row">
                    <div class="data-label">Status:</div>
                    <div class="data-value">Unusable - Noise exceeds signal</div>
                </div>
            `;
        } else if (snr >= 0 && snr <= 15) {
            resultDiv.innerHTML = `
                <div class="result-alert warning">
                    <div class="result-icon">⚠️</div>
                    <div class="result-content">
                        <div class="result-title">Poor Signal Quality</div>
                        <div class="result-details">
                            SNR is ${snr} dB. Devices may experience association issues, intermittent connectivity,
                            reduced throughput, and increased packet loss due to poor signal quality.
                        </div>
                    </div>
                </div>
                <div class="data-row">
                    <div class="data-label">Calculated SNR:</div>
                    <div class="data-value highlight">${snr} dB</div>
                </div>
                <div class="data-row">
                    <div class="data-label">Signal Strength:</div>
                    <div class="data-value">${signal} dBm</div>
                </div>
                <div class="data-row">
                    <div class="data-label">Noise Level:</div>
                    <div class="data-value">${noise} dBm</div>
                </div>
                <div class="data-row">
                    <div class="data-label">Status:</div>
                    <div class="data-value">Poor - Improvement recommended</div>
                </div>
                <div class="data-row">
                    <div class="data-label">Recommendation:</div>
                    <div class="data-value">Increase signal strength or reduce noise interference for better performance</div>
                </div>
            `;
        } else {
            resultDiv.innerHTML = `
                <div class="result-alert success">
                    <div class="result-icon">✓</div>
                    <div class="result-content">
                        <div class="result-title">Good Signal Quality</div>
                        <div class="result-details">
                            SNR is ${snr} dB. Devices should associate and operate without issues.
                            This signal quality supports reliable wireless connectivity and good throughput.
                        </div>
                    </div>
                </div>
                <div class="data-row">
                    <div class="data-label">Calculated SNR:</div>
                    <div class="data-value highlight">${snr} dB</div>
                </div>
                <div class="data-row">
                    <div class="data-label">Signal Strength:</div>
                    <div class="data-value">${signal} dBm</div>
                </div>
                <div class="data-row">
                    <div class="data-label">Noise Level:</div>
                    <div class="data-value">${noise} dBm</div>
                </div>
                <div class="data-row">
                    <div class="data-label">Status:</div>
                    <div class="data-value">Good - Acceptable for wireless connectivity</div>
                </div>
            `;
        }

        // Scroll to results
        resultSection.scrollIntoView({ behavior: 'smooth', block: 'start' });
    }

    // Add enter key support
    document.addEventListener('DOMContentLoaded', function() {
        document.getElementById('signal').addEventListener('keypress', function(e) {
            if (e.key === 'Enter') {
                snr();
            }
        });

        document.getElementById('noise').addEventListener('keypress', function(e) {
            if (e.key === 'Enter') {
                snr();
            }
        });
    });
</script>