Spectrum
DVB-C / Spectrum
On the "Spectrum" page you receive various technical information about the TV channels found on the cable connection. The details about signal quality can help you narrow down the possible cause when TV reception is disrupted.
Generating TV Cable Spectrum
Overview
The following views are available for the spectrum:
| View | Contents |
|---|---|
| TV channels found | List of the stations found in the spectrum of your cable connection, along with their technical parameters |
| Frequency spectrum | Course of the signal strength over the frequency spectrum of your cable connection |
Instructions: Generating TV Cable Spectrum
- Select the desired view.
- Click on the "Generate Spectrum" button.
Information in the "TV channels found" View
When you move the mouse cursor over the bars, you receive the following information:
| Information | Description |
|---|---|
| TV Channel | The channels found are grouped in bouquets. A bouquet is a group of several digital TV channels. The message "No channel information available" is displayed for encrypted channels and for bouquets containing only encrypted channels. |
| Frequency | Frequency (MHz) |
| Signal Quality | Possible values: good, weak, distorted If TV reception is disrupted, the details about signal quality can help you isolate the possible cause. If the signal quality is "distorted", the problem is caused by an incorrect setting on the cable amplifier. If the signal quality is "weak", the problem is caused by the cable provider, by intensive utilization of the TV channels, by network fluctuations, or by the cabling. |
| Signal Strength | Signal strength in dBmV (power level). Indicates the voltage level. The signal strength provided by the cable TV provider is standardized. |
| SNR | Signal-to-noise ratio in dB SNR stands for signal-to-noise ratio and is a measure of the strength of the signal as related to the background noise. The higher the SNR, the better the signal transmission. |
| Modulation | For internet connections over cable, the QAM (quadrature amplitude modulation) method is used. The QAM value depends on the line quality. The QAM value depends on the line quality. |
| ONID | Stands for "Original Network ID" and describes the location of the data stream's origin when digital content is transmitted. |
| TSID | Stands for "Transport Stream Identifier" and serves as a unique identifier of the data channels. |
Information in the Frequency Spectrum
The frequency spectrum shows the course of the signal strength for your cable connection. This provides an overview of which TV channels are received in what quality.
Parameters for the Quality of TV Reception
Overview
The signal quality of TV reception is determined by the relationship between the signal strength and the signal-to-noise ratio. A low signal strength can be compensated by a high signal-to-noise ratio, and vice versa.
Signal Strength
| Value in dBmV | Rating |
|---|---|
| -7 to +7 | recommended |
| between -8 and -10 +8 and +10 | acceptable |
| between -11 and -15 +11 and +15 | Maximum with possible limitations |
| lower than -15 or higher than +15 | poor |
Signal-to-Noise Ratio (SNR)
A higher signal-to-noise ratio means better TV reception.
| Modulation Method | Value in dB | Rating |
|---|---|---|
| QAM64 | 24 | Minimum |
| QAM64 | > 27 | recommended |
| QAM256 | 30 | Minimum |
| QAM256 | > 33 | recommended |