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Chapter 6 - TV Measuring Range
10713 Vxx.11
Scan
6.2.2.3.2
You can use this function to scan the entire TV range for DVB-T signals.
You must switch the instrument to channel input mode to use the scan function.
In the digital operating mode, the arrow keys have a dual function. After entry of a new channel, the
menu item
2.FUNCTION
is inverted. That means that the MPEG decoder can be operated with the
arrow keys. To start the scan, first press the
F5
key in order to activate the first function of the
arrow keys.
The scan is then started by first tuning the measuring receiver to a channel at which the scan
should begin. Press the
↑
key to start the scan in the positive direction. Press the
↓
key to do the
same in the negative direction. When the band limit is reached, the scan continues at the other end
of the range. You can end the scan at any time by pressing
ENTER
. “SCAN” is shown on the
display while the scan takes place
DVB-T parameters
6.2.2.3.3
As soon as the receiver has completed the synchronization process, several parameters are shown
on the display. When LOCK appears, it means that the digital receiver is receiving a valid data
stream. In contrast, UNLK means that either the quality of the signal that is present is insufficient,
or that the parameters of the receiver do not agree, or that no DVB-T signal can be received at this
frequency.
Figure 6-12 DVB-T parameters
Once the receiver is synchronized, additional parameters are shown on the display. The DVB-T
receiver determines these automatically.
With COFDM, a multi-carrier method is involved. The single carriers within the DVB-T signal are
QPSK, 16QAM or 64QAM modulated. Figure 6-12 shows transmission with the modulation scheme
16QAM.
The DVB-T standard specified two FFT modes (2k or 8k). In the top line, you can see the currently
determined FFT mode.
Additional parameters are the Guard Interval (GI), FEC (Forward Error Correction) and the network
identification number (ID). These are displayed in the line above the menu bar.
