.. titel: RF Signal-to-Noise Ratio (SNR) Lommeregner
.. snegl: rf-signaltonoiseratio
.. dato: 26-12-2025 15:00:00 UTC
.. tags: netværk, lommeregner, værktøj
.. kategori: Lommeregnere
.. link:
.. beskrivelse: Beregn signal-til-støj-forhold (SNR) i dB ud fra signal- og støjeffekt. Evaluer trådløs forbindelseskvalitet, diagnosticer interferens, og forudsig modulationsopnåelighed.
.. type: tekst
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</style>
<div class="calc-container">
<div class="calc-header">
<h2>Lommeregner for RF-signal til støjforhold</h2>
<p>Beregn Signal-to-Noise Ratio (SNR) for at bestemme kvaliteten af ​​det trådløse signal og forudsige problemer med enhedens forbindelse.</p>
<div class="form-group">
<div class="form-row">
<div class="input-wrapper">
<label class="input-label" for="signal">Signalstyrke (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">Støjniveau (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">Beregn SNR</button>
</div>
<div class="help-text">
<strong>Note:</strong>SNR beregnes som Signal - Støj. Højere værdier indikerer bedre signalkvalitet. Et minimum SNR på 15-20 dB anbefales for pålidelig trådløs forbindelse.</div>
</div>
<div class="result-section" id="resultSection">
<div class="section-header">
<h3><span class="icon">📊</span>Resultater</h3>
</div>
<div class="section-content">
<div id="snrResult"></div>
</div>
</div>
<div class="info-section">
<h4>Forstå signal-til-støj-forhold (SNR)</h4>
<p>Signal-til-støj-forholdet er en kritisk målestok i trådløs kommunikation, der måler styrken af ​​det ønskede signal i forhold til baggrundsstøj.
            Det beregnes ved at trække støjniveauet fra signalstyrken (begge i dBm).</p>
<p>
<strong>SNR kvalitetsretningslinjer:</strong>
</p>
<table class="snr-table">
<thead>
<tr>
<th>SNR rækkevidde</th>
<th>Kvalitet</th>
<th>Forventet ydeevne</th>
</tr>
</thead>
<tbody>
<tr>
<td>40+ dB</td>
<td>Fremragende</td>
<td>Maksimal gennemløb, intet pakketab</td>
</tr>
<tr>
<td>25-40 dB</td>
<td>Meget god</td>
<td>Høj gennemstrømning, minimale problemer</td>
</tr>
<tr>
<td>15-25 dB</td>
<td>God</td>
<td>Pålidelig tilslutning, moderat gennemløb</td>
</tr>
<tr>
<td>10-15 dB</td>
<td>Retfærdig</td>
<td>Grundlæggende tilslutning, muligt pakketab</td>
</tr>
<tr>
<td>5-10 dB</td>
<td>Dårlig</td>
<td>Ustabil forbindelse, hyppige afbrydelser</td>
</tr>
<tr>
<td>&lt; 5 dB</td>
<td>Meget ringe</td>
<td>Ubrugelig, forbindelsesfejl</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>