Method for ensuring the stability of received signal level of t2 frame and its level step detection device
A technology for receiving signals and levels, applied in the field of communication, can solve the problems of unknown insertion format, affecting the detection and decoding of P1 symbols, and missing channels.
Active Publication Date: 2017-09-15
上海明波通信技术股份有限公司
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[0010] However, before P1 symbol detection and P1 symbol decoding, it is unknown whether there is a FEF frame and the insertion format of the FEF frame, etc.
At this time, the FEF frame signal may disturb the receiving level of the T2 frame signal, thereby affecting the detection and decoding of the P1 symbol, and the decoding of the P2 symbol. In severe cases, the scanning of the T2 channel fails, and the channel is missed.
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[0044] Figure 4a , 4b Displays the fluctuation of the AGC output signal level when there are FEF frames. Figure 4a As shown, when the signal power of the FEF frame is small, the signal level of the FEF part (except the P1 symbol) jumps downward, and as the AGC gradually converges, the signal level finally returns to the normal value; on the other hand, the T2 frame The signal level jumps upwards, then its level gradually decreases, and finally returns to the normal signal level. Figure 4b As shown, when the power of the FEF signal is high, the FEF signal (except the P1 symbol) undergoes an upward transition, while the T2 signal undergoes a downward transition. Obviously, when the received level of the P1 symbol and the subsequent P2 symbol is far from its normal signal level, it will have a serious impact on symbol detection and decoding.
[0045] Figure 5 As shown, it is a processing flowchart of an embodiment of the present invention, within the first predetermined t...
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The invention discloses a method for ensuring the stability of the received signal level of the T2 frame. In the first predetermined time, the synchronous position detection of the P1 symbol and the level step position detection are performed, and the AGC control voltage value is recorded; the FEF frame position is found out and used The control voltage before the level step implements open-loop control on the AGC; if the P1 symbol detection fails under this condition, or the FEF frame position cannot be found within the first predetermined time, three consecutive level steps are detected within the second predetermined time jump, and generate a periodic AGC freeze signal, if the P1 symbol detection is successful under this condition, the AGC freeze signal is used to freeze the AGC during the FEF signal; if the P1 symbol detection fails, return to re-execute this method within the third predetermined time, Exceeding the third predetermined time, the system jumps out of execution. The invention also discloses a level step detection device used in the method. The invention can prevent the FEF frame signal from disturbing the receiving level of the T2 frame signal, and can improve the performance of P1 symbol detection and decoding and P2 symbol decoding.
Description
technical field [0001] The invention relates to the communication field, in particular to a method for ensuring the stability of the received signal level of the T2 frame of the second-generation European terrestrial digital television (DVB-T2). The invention also relates to a level step detection device used in the method. Background technique [0002] DVB-T2 ("Digital Video Broadcasting (DVB); Frame structure channel coding and modulation for a second generation digital terrestrial television broadcasting system (DVB-T2)," ETSI EN 302 755), adopted OFDM technology, the basic unit of its data is called T2 frame. For future data application expansion, the DVB-T2 standard defines a future data frame (FEF: Future Extension Frame), which is time-multiplexed with the T2 frame and sent together. figure 1 Shown is the DVB-T2 system frame structure diagram. Such as figure 1 As shown, the T2 frame and the FEF frame are time-division multiplexed. Of course, FEF frames are insert...
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IPC IPC(8): H04H20/72H04L27/26
Inventor 王薇漪龙必起陈小元
Owner 上海明波通信技术股份有限公司