CN114221729A - FM-CDR emergency broadcast message receiving method without clearing buffer area - Google Patents

Abstract

The invention relates to a receiving method of FM-CDR emergency broadcast messages without a buffer area, which comprises a CDR tuning demodulation module, a CDR transmission stream buffer area and a main control module, wherein FM-CDR signals are circularly received, an emergency broadcast index table in a corresponding CDR transmission stream is detected, if overtime happens, one detection is finished, and when the index table is analyzed and a message target area in the index table is matched with a local machine, the receiving is carried out; particularly, after the CDR tuning demodulation module starts to receive the FM-CDR signal, it first waits for a time period T3, so that the CDR transport stream of the current receiving frequency is fully written into the CDR transport stream buffer, and the old data is overwritten. The invention realizes the judgment of whether the FM-CDR emergency broadcast message sent to the local machine exists and the reception, and prevents the detection distortion and the reception distortion of the FM-CDR emergency broadcast message.

Description

FM-CDR emergency broadcast message receiving method without clearing buffer area

Technical Field

The invention belongs to the technical field of emergency broadcasting, and particularly relates to a method for receiving FM-CDR emergency broadcast messages without clearing a buffer area.

Background

The emergency broadcast system consists of an emergency broadcast platform, an adapter, a transmission coverage system and an emergency broadcast terminal, wherein the emergency broadcast platform transmits emergency broadcast messages to the emergency broadcast terminal for playing through the adapter and the transmission coverage system. The emergency broadcast message includes an emergency broadcast instruction and emergency broadcast content. Emergency broadcast content is message incidental content (text, audio-video) or parameters specifying a broadcast television program.

When a sudden disaster is faced, the government can timely convey politics, release authority information, guide social public opinion and actively assist in disaster relief by using the emergency broadcasting system. The emergency broadcast can reach the emergency broadcast terminal singly or in a relay mode through a plurality of transmission coverage networks. Current broadcast television transmission coverage includes digital frequency modulation (FM-CDR). The national specification for FM-CDR includes "part 1 of FM-band digital audio broadcasting: digital broadcast channel frame structure, channel coding and modulation, part 2 of fm band digital audio broadcasting: multiplexing ], and the like.

The FM-CDR emergency broadcast message is an emergency broadcast message sent by an FM-CDR transmission and transmission system. How to receive FM-CDR emergency broadcast messages by emergency broadcast terminals and adapters is a technical problem to be solved.

Disclosure of Invention

The technical problem to be solved by the invention is how to receive FM-CDR emergency broadcast messages and transmit the emergency broadcast messages from an FM-CDR transmission coverage system to an emergency broadcast terminal and an adapter.

The technical scheme of the invention is as follows.

FM-CDR emergency broadcast message receiving method without a buffer, N FM-CDR frequencies are possible to receive FM-CDR emergency broadcast messages, and the FM-CDR emergency broadcast messages are in a CDR data packet with PID = = PID _ sel, characterized in that the N FM-CDR frequency values are included in a frequency array F [ N ], FM-CDR signals of all frequencies in the F [ N ] are circularly detected, wherein one processing procedure comprises the following steps, the current detected frequency is known as a frequency F [ i ], and the detection time is T:

step 1, a main control module sets the receiving frequency of a CDR tuning demodulation module as a current detection frequency;

step 2, the CDR tuning demodulation module performs tuning demodulation on the FM-CDR signal according to the receiving frequency to obtain a CDR transmission stream, and the CDR transmission stream is written into a CDR transmission stream buffer area;

step 3, waiting for a time period T3, so that the CDR transmission stream of the current receiving frequency is fully written into the CDR transmission stream buffer area to cover the old data, and the old data in the CDR transmission stream buffer area does not need to be cleared specially first;

step 4, filtering a data packet corresponding to the emergency broadcast message in the CDR transport stream from the CDR transport stream buffer area according to PID = = PID _ sel;

step 5, in time period T, the main control module retrieves and extracts the emergency broadcast index table from the data packet, if overtime, the detection of the receiving frequency is ended, and step 8 is executed;

step 6, if the message target area in the emergency broadcast index table is matched with the local machine, step 7 is executed, otherwise step 8 is executed;

step 7, the main control module extracts an emergency broadcast index table and an emergency broadcast content table from the data packet to further obtain a CDR emergency broadcast message;

and 8, the main control module changes the current detection frequency to be F [ j ], wherein j = i +1, and j =0 if j = = array length.

Preferably, the core of the CDR tuning demodulation module is a heler Hi5216 chip.

Compared with the prior art, the invention has the beneficial effects that:

1. according to the frequency in the receiving frequency array F [ n ], the FM-CDR signals are circularly received, CDR transmission stream data are detected, and when an emergency broadcast index table is obtained through analysis and a message target area in the emergency broadcast index table is matched with the local machine, the FM-CDR emergency broadcast messages sent to the local machine are judged. This enables how to find FM-CDR emergency broadcast messages addressed to the local machine in at least 1 frequency.

2. The CDR tuning demodulation module, the CDR transmission stream buffer area and the main control module are used for detecting and receiving the FM-CDR emergency broadcast message.

3. After the CDR tuning demodulation module starts to receive the FM-CDR signal each time, waiting for a time period T3, the CDR transmission stream of the new frequency is fully written into the first CDR transmission stream buffer area without specially clearing the old data in the first CDR transmission stream buffer area. This prevents the master control module from detecting the emergency broadcast index table of the CDR transport stream data of the new frequency, i.e., preventing detection distortion and reception distortion, because the CDR transport stream data of the new frequency is not as long as the CDR transport stream data covering the old frequency.

Drawings

Fig. 1 is a block diagram of the structure of the embodiment of the present invention.

FIG. 2 is a flowchart of a method of a process according to an embodiment of the present invention.

Detailed Description

The following detailed description of embodiments of the invention refers to the accompanying drawings and examples.

As shown in fig. 1-2, the FM-CDR emergency broadcast message receiving method without a buffer, where there are N FM-CDR frequencies that may receive FM-CDR emergency broadcast messages, and the FM-CDR emergency broadcast messages are in a CDR packet with PID = = PID _ sel, is characterized in that the N FM-CDR frequency values are included in a frequency array F [ N ], and FM-CDR signals of all frequencies in the F [ N ] are cyclically detected, wherein a processing procedure includes the following steps, and the currently detected frequency is known as a frequency F [ i ], and the detection time is T:

step 1, a main control module sets the receiving frequency of a CDR tuning demodulation module as a current detection frequency;

step 2, the CDR tuning demodulation module performs tuning demodulation on the FM-CDR signal according to the receiving frequency to obtain a CDR transmission stream, and the CDR transmission stream is written into a CDR transmission stream buffer area;

step 3, waiting for a time period T3, so that the CDR transmission stream of the current receiving frequency is fully written into the CDR transmission stream buffer area to cover the old data, and the old data in the CDR transmission stream buffer area does not need to be cleared specially first;

step 4, filtering a data packet corresponding to the emergency broadcast message in the CDR transport stream from the CDR transport stream buffer area according to PID = = PID _ sel;

step 5, in time period T, the main control module retrieves and extracts the emergency broadcast index table from the data packet, if overtime, the detection of the receiving frequency is ended, and step 8 is executed;

step 6, if the message target area in the emergency broadcast index table is matched with the local machine, step 7 is executed, otherwise step 8 is executed;

step 7, the main control module extracts an emergency broadcast index table and an emergency broadcast content table from the data packet to further obtain a CDR emergency broadcast message;

and 8, the main control module changes the current detection frequency to be F [ j ], wherein j = i +1, and j =0 if j = = array length.

Preferably, the core of the CDR tuning demodulation module is a heler Hi5216 chip.

The beneficial effects are that:

1. according to the frequency in the receiving frequency array F [ n ], the FM-CDR signals are circularly received, CDR transmission stream data are detected, and when an emergency broadcast index table is obtained through analysis and a message target area in the emergency broadcast index table is matched with the local machine, the FM-CDR emergency broadcast messages sent to the local machine are judged. This enables how to find FM-CDR emergency broadcast messages addressed to the local machine in at least 1 frequency.

2. The CDR tuning demodulation module, the CDR transmission stream buffer area and the main control module are used for detecting and receiving the FM-CDR emergency broadcast message.

3. After the CDR tuning demodulation module starts to receive the FM-CDR signal each time, waiting for a time period T3, the CDR transmission stream of the new frequency is fully written into the first CDR transmission stream buffer area without specially clearing the old data in the first CDR transmission stream buffer area. This prevents the master control module from detecting the emergency broadcast index table of the CDR transport stream data of the new frequency, i.e., preventing detection distortion and reception distortion, because the CDR transport stream data of the new frequency is not as long as the CDR transport stream data covering the old frequency.

The present invention has been described in terms of embodiments, and it will be appreciated that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the scope and spirit of the principles of this disclosure. More specifically, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, other uses will also be apparent to those skilled in the art.

All of the features disclosed in this specification, or all of the steps in any method or process so disclosed, may be combined in any combination, except combinations of features and/or steps that are mutually exclusive.

Any feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving equivalent or similar purposes, unless expressly stated otherwise. That is, unless expressly stated otherwise, each feature is only an example of a generic series of equivalent or similar features.

Claims (2)

1. FM-CDR emergency broadcast message receiving method without a buffer, N FM-CDR frequencies are possible to receive FM-CDR emergency broadcast messages, and the FM-CDR emergency broadcast messages are in a CDR data packet with PID = = PID _ sel, characterized in that the N FM-CDR frequency values are included in a frequency array F [ N ], FM-CDR signals of all frequencies in the F [ N ] are circularly detected, wherein one processing procedure comprises the following steps, the current detected frequency is known as a frequency F [ i ], and the detection time is T:

step 1, a main control module sets the receiving frequency of a CDR tuning demodulation module as a current detection frequency;

step 2, the CDR tuning demodulation module performs tuning demodulation on the FM-CDR signal according to the receiving frequency to obtain a CDR transmission stream, and the CDR transmission stream is written into a CDR transmission stream buffer area;

step 3, waiting for a time period T3, so that the CDR transmission stream of the current receiving frequency is fully written into the CDR transmission stream buffer area to cover the old data, and the old data in the CDR transmission stream buffer area does not need to be cleared specially first;

step 4, filtering a data packet corresponding to the emergency broadcast message in the CDR transport stream from the CDR transport stream buffer area according to PID = = PID _ sel;

step 5, in time period T, the main control module retrieves and extracts the emergency broadcast index table from the data packet, if overtime, the detection of the receiving frequency is ended, and step 8 is executed;

step 6, if the message target area in the emergency broadcast index table is matched with the local machine, step 7 is executed, otherwise step 8 is executed;

step 7, the main control module extracts an emergency broadcast index table and an emergency broadcast content table from the data packet to further obtain a CDR emergency broadcast message;

and 8, the main control module changes the current detection frequency to be F [ j ], wherein j = i +1, and j =0 if j = = array length.

2. The unbuffered FM-CDR emergency broadcast message receiving method of claim 1, wherein a core of the CDR tuning demodulation module is a Hi5216 chip.

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